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linux-next/arch/powerpc/kvm/book3s_hv_rmhandlers.S

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KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*
* Derived from book3s_rmhandlers.S and other files, which are:
*
* Copyright SUSE Linux Products GmbH 2009
*
* Authors: Alexander Graf <agraf@suse.de>
*/
#include <asm/ppc_asm.h>
#include <asm/kvm_asm.h>
#include <asm/reg.h>
KVM: PPC: Assemble book3s{,_hv}_rmhandlers.S separately This makes arch/powerpc/kvm/book3s_rmhandlers.S and arch/powerpc/kvm/book3s_hv_rmhandlers.S be assembled as separate compilation units rather than having them #included in arch/powerpc/kernel/exceptions-64s.S. We no longer have any conditional branches between the exception prologs in exceptions-64s.S and the KVM handlers, so there is no need to keep their contents close together in the vmlinux image. In their current location, they are using up part of the limited space between the first-level interrupt handlers and the firmware NMI data area at offset 0x7000, and with some kernel configurations this area will overflow (e.g. allyesconfig), leading to an "attempt to .org backwards" error when compiling exceptions-64s.S. Moving them out requires that we add some #includes that the book3s_{,hv_}rmhandlers.S code was previously getting implicitly via exceptions-64s.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:41:11 +08:00
#include <asm/mmu.h>
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
#include <asm/page.h>
KVM: PPC: Assemble book3s{,_hv}_rmhandlers.S separately This makes arch/powerpc/kvm/book3s_rmhandlers.S and arch/powerpc/kvm/book3s_hv_rmhandlers.S be assembled as separate compilation units rather than having them #included in arch/powerpc/kernel/exceptions-64s.S. We no longer have any conditional branches between the exception prologs in exceptions-64s.S and the KVM handlers, so there is no need to keep their contents close together in the vmlinux image. In their current location, they are using up part of the limited space between the first-level interrupt handlers and the firmware NMI data area at offset 0x7000, and with some kernel configurations this area will overflow (e.g. allyesconfig), leading to an "attempt to .org backwards" error when compiling exceptions-64s.S. Moving them out requires that we add some #includes that the book3s_{,hv_}rmhandlers.S code was previously getting implicitly via exceptions-64s.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:41:11 +08:00
#include <asm/ptrace.h>
#include <asm/hvcall.h>
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
#include <asm/asm-offsets.h>
#include <asm/exception-64s.h>
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
#include <asm/kvm_book3s_asm.h>
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
#include <asm/mmu-hash64.h>
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
#include <asm/tm.h>
#define VCPU_GPRS_TM(reg) (((reg) * ULONG_SIZE) + VCPU_GPR_TM)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Values in HSTATE_NAPPING(r13) */
#define NAPPING_CEDE 1
#define NAPPING_NOVCPU 2
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/*
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
* Call kvmppc_hv_entry in real mode.
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
* Must be called with interrupts hard-disabled.
*
* Input Registers:
*
* LR = return address to continue at after eventually re-enabling MMU
*/
KVM: PPC: Assembly functions exported to modules need _GLOBAL_TOC() Both kvmppc_hv_entry_trampoline and kvmppc_entry_trampoline are assembly functions that are exported to modules and also require a valid r2. As such we need to use _GLOBAL_TOC so we provide a global entry point that establishes the TOC (r2). Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-12 16:16:53 +08:00
_GLOBAL_TOC(kvmppc_hv_entry_trampoline)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -112(r1)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
mfmsr r10
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
LOAD_REG_ADDR(r5, kvmppc_call_hv_entry)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
li r0,MSR_RI
andc r0,r10,r0
li r6,MSR_IR | MSR_DR
andc r6,r10,r6
mtmsrd r0,1 /* clear RI in MSR */
mtsrr0 r5
mtsrr1 r6
RFI
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
kvmppc_call_hv_entry:
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
ld r4, HSTATE_KVM_VCPU(r13)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
bl kvmppc_hv_entry
/* Back from guest - restore host state and return to caller */
KVM: PPC: Book3S HV: Don't set DABR on POWER8 POWER8 doesn't have the DABR and DABRX registers; instead it has new DAWR/DAWRX registers, which will be handled in a later patch. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:19 +08:00
BEGIN_FTR_SECTION
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
/* Restore host DABR and DABRX */
ld r5,HSTATE_DABR(r13)
li r6,7
mtspr SPRN_DABR,r5
mtspr SPRN_DABRX,r6
KVM: PPC: Book3S HV: Don't set DABR on POWER8 POWER8 doesn't have the DABR and DABRX registers; instead it has new DAWR/DAWRX registers, which will be handled in a later patch. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:19 +08:00
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
/* Restore SPRG3 */
powerpc/booke64: Use SPRG7 for VDSO Previously SPRG3 was marked for use by both VDSO and critical interrupts (though critical interrupts were not fully implemented). In commit 8b64a9dfb091f1eca8b7e58da82f1e7d1d5fe0ad ("powerpc/booke64: Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman made an attempt to resolve this conflict by restoring the VDSO value early in the critical interrupt, but this has some issues: - It's incompatible with EXCEPTION_COMMON which restores r13 from the by-then-overwritten scratch (this cost me some debugging time). - It forces critical exceptions to be a special case handled differently from even machine check and debug level exceptions. - It didn't occur to me that it was possible to make this work at all (by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after I made (most of) this patch. :-) It might be worth investigating using a load rather than SPRG on return from all exceptions (except TLB misses where the scratch never leaves the SPRG) -- it could save a few cycles. Until then, let's stick with SPRG for all exceptions. Since we cannot use SPRG4-7 for scratch without corrupting the state of a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor critical interrupts exist on book3s, SPRG3 is still used for VDSO there. Signed-off-by: Scott Wood <scottwood@freescale.com> Cc: Mihai Caraman <mihai.caraman@freescale.com> Cc: Anton Blanchard <anton@samba.org> Cc: Paul Mackerras <paulus@samba.org> Cc: kvm-ppc@vger.kernel.org
2014-03-11 06:29:38 +08:00
ld r3,PACA_SPRG_VDSO(r13)
mtspr SPRN_SPRG_VDSO_WRITE,r3
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
/* Reload the host's PMU registers */
ld r3, PACALPPACAPTR(r13) /* is the host using the PMU? */
lbz r4, LPPACA_PMCINUSE(r3)
cmpwi r4, 0
beq 23f /* skip if not */
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs This adds workarounds for two hardware bugs in the POWER8 performance monitor unit (PMU), both related to interrupt generation. The effect of these bugs is that PMU interrupts can get lost, leading to tools such as perf reporting fewer counts and samples than they should. The first bug relates to the PMAO (perf. mon. alert occurred) bit in MMCR0; setting it should cause an interrupt, but doesn't. The other bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0. Setting PMAE when a counter is negative and counter negative conditions are enabled to cause alerts should cause an alert, but doesn't. The workaround for the first bug is to create conditions where a counter will overflow, whenever we are about to restore a MMCR0 value that has PMAO set (and PMAO_SYNC clear). The workaround for the second bug is to freeze all counters using MMCR2 before reading MMCR0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-26 17:48:40 +08:00
BEGIN_FTR_SECTION
powerpc/kvm: Create proper names for the kvm_host_state PMU fields We have two arrays in kvm_host_state that contain register values for the PMU. Currently we only create an asm-offsets symbol for the base of the arrays, and do the array offset in the assembly code. Creating an asm-offsets symbol for each field individually makes the code much nicer to read, particularly for the MMCRx/SIxR/SDAR fields, and might have helped us notice the recent double restore bug we had in this code. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Alexander Graf <agraf@suse.de>
2014-07-10 17:34:31 +08:00
ld r3, HSTATE_MMCR0(r13)
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs This adds workarounds for two hardware bugs in the POWER8 performance monitor unit (PMU), both related to interrupt generation. The effect of these bugs is that PMU interrupts can get lost, leading to tools such as perf reporting fewer counts and samples than they should. The first bug relates to the PMAO (perf. mon. alert occurred) bit in MMCR0; setting it should cause an interrupt, but doesn't. The other bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0. Setting PMAE when a counter is negative and counter negative conditions are enabled to cause alerts should cause an alert, but doesn't. The workaround for the first bug is to create conditions where a counter will overflow, whenever we are about to restore a MMCR0 value that has PMAO set (and PMAO_SYNC clear). The workaround for the second bug is to freeze all counters using MMCR2 before reading MMCR0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-26 17:48:40 +08:00
andi. r4, r3, MMCR0_PMAO_SYNC | MMCR0_PMAO
cmpwi r4, MMCR0_PMAO
beql kvmppc_fix_pmao
END_FTR_SECTION_IFSET(CPU_FTR_PMAO_BUG)
powerpc/kvm: Create proper names for the kvm_host_state PMU fields We have two arrays in kvm_host_state that contain register values for the PMU. Currently we only create an asm-offsets symbol for the base of the arrays, and do the array offset in the assembly code. Creating an asm-offsets symbol for each field individually makes the code much nicer to read, particularly for the MMCRx/SIxR/SDAR fields, and might have helped us notice the recent double restore bug we had in this code. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Alexander Graf <agraf@suse.de>
2014-07-10 17:34:31 +08:00
lwz r3, HSTATE_PMC1(r13)
lwz r4, HSTATE_PMC2(r13)
lwz r5, HSTATE_PMC3(r13)
lwz r6, HSTATE_PMC4(r13)
lwz r8, HSTATE_PMC5(r13)
lwz r9, HSTATE_PMC6(r13)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
mtspr SPRN_PMC1, r3
mtspr SPRN_PMC2, r4
mtspr SPRN_PMC3, r5
mtspr SPRN_PMC4, r6
mtspr SPRN_PMC5, r8
mtspr SPRN_PMC6, r9
powerpc/kvm: Create proper names for the kvm_host_state PMU fields We have two arrays in kvm_host_state that contain register values for the PMU. Currently we only create an asm-offsets symbol for the base of the arrays, and do the array offset in the assembly code. Creating an asm-offsets symbol for each field individually makes the code much nicer to read, particularly for the MMCRx/SIxR/SDAR fields, and might have helped us notice the recent double restore bug we had in this code. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Alexander Graf <agraf@suse.de>
2014-07-10 17:34:31 +08:00
ld r3, HSTATE_MMCR0(r13)
ld r4, HSTATE_MMCR1(r13)
ld r5, HSTATE_MMCRA(r13)
ld r6, HSTATE_SIAR(r13)
ld r7, HSTATE_SDAR(r13)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
mtspr SPRN_MMCR1, r4
mtspr SPRN_MMCRA, r5
KVM: PPC: Book3S HV: Save/restore host PMU registers that are new in POWER8 Currently we save the host PMU configuration, counter values, etc., when entering a guest, and restore it on return from the guest. (We have to do this because the guest has control of the PMU while it is executing.) However, we missed saving/restoring the SIAR and SDAR registers, as well as the registers which are new on POWER8, namely SIER and MMCR2. This adds code to save the values of these registers when entering the guest and restore them on exit. This also works around the bug in POWER8 where setting PMAE with a counter already negative doesn't generate an interrupt. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:08 +08:00
mtspr SPRN_SIAR, r6
mtspr SPRN_SDAR, r7
BEGIN_FTR_SECTION
powerpc/kvm: Create proper names for the kvm_host_state PMU fields We have two arrays in kvm_host_state that contain register values for the PMU. Currently we only create an asm-offsets symbol for the base of the arrays, and do the array offset in the assembly code. Creating an asm-offsets symbol for each field individually makes the code much nicer to read, particularly for the MMCRx/SIxR/SDAR fields, and might have helped us notice the recent double restore bug we had in this code. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Alexander Graf <agraf@suse.de>
2014-07-10 17:34:31 +08:00
ld r8, HSTATE_MMCR2(r13)
ld r9, HSTATE_SIER(r13)
KVM: PPC: Book3S HV: Save/restore host PMU registers that are new in POWER8 Currently we save the host PMU configuration, counter values, etc., when entering a guest, and restore it on return from the guest. (We have to do this because the guest has control of the PMU while it is executing.) However, we missed saving/restoring the SIAR and SDAR registers, as well as the registers which are new on POWER8, namely SIER and MMCR2. This adds code to save the values of these registers when entering the guest and restore them on exit. This also works around the bug in POWER8 where setting PMAE with a counter already negative doesn't generate an interrupt. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:08 +08:00
mtspr SPRN_MMCR2, r8
mtspr SPRN_SIER, r9
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
mtspr SPRN_MMCR0, r3
isync
23:
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/*
* Reload DEC. HDEC interrupts were disabled when
* we reloaded the host's LPCR value.
*/
ld r3, HSTATE_DECEXP(r13)
mftb r4
subf r4, r4, r3
mtspr SPRN_DEC, r4
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
/*
* For external and machine check interrupts, we need
* to call the Linux handler to process the interrupt.
* We do that by jumping to absolute address 0x500 for
* external interrupts, or the machine_check_fwnmi label
* for machine checks (since firmware might have patched
* the vector area at 0x200). The [h]rfid at the end of the
* handler will return to the book3s_hv_interrupts.S code.
* For other interrupts we do the rfid to get back
* to the book3s_hv_interrupts.S code here.
*/
ld r8, 112+PPC_LR_STKOFF(r1)
addi r1, r1, 112
ld r7, HSTATE_HOST_MSR(r13)
cmpwi cr1, r12, BOOK3S_INTERRUPT_MACHINE_CHECK
cmpwi r12, BOOK3S_INTERRUPT_EXTERNAL
beq 11f
powerpc/book3s: Add basic infrastructure to handle HMI in Linux. Handle Hypervisor Maintenance Interrupt (HMI) in Linux. This patch implements basic infrastructure to handle HMI in Linux host. The design is to invoke opal handle hmi in real mode for recovery and set irq_pending when we hit HMI. During check_irq_replay pull opal hmi event and print hmi info on console. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-29 21:10:01 +08:00
cmpwi cr2, r12, BOOK3S_INTERRUPT_HMI
beq cr2, 14f /* HMI check */
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
/* RFI into the highmem handler, or branch to interrupt handler */
mfmsr r6
li r0, MSR_RI
andc r6, r6, r0
mtmsrd r6, 1 /* Clear RI in MSR */
mtsrr0 r8
mtsrr1 r7
beq cr1, 13f /* machine check */
RFI
/* On POWER7, we have external interrupts set to use HSRR0/1 */
11: mtspr SPRN_HSRR0, r8
mtspr SPRN_HSRR1, r7
ba 0x500
13: b machine_check_fwnmi
powerpc/book3s: Add basic infrastructure to handle HMI in Linux. Handle Hypervisor Maintenance Interrupt (HMI) in Linux. This patch implements basic infrastructure to handle HMI in Linux host. The design is to invoke opal handle hmi in real mode for recovery and set irq_pending when we hit HMI. During check_irq_replay pull opal hmi event and print hmi info on console. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-07-29 21:10:01 +08:00
14: mtspr SPRN_HSRR0, r8
mtspr SPRN_HSRR1, r7
b hmi_exception_after_realmode
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
kvmppc_primary_no_guest:
/* We handle this much like a ceded vcpu */
KVM: PPC: Book3S HV: Use decrementer to wake napping threads This arranges for threads that are napping due to their vcpu having ceded or due to not having a vcpu to wake up at the end of the guest's timeslice without having to be poked with an IPI. We do that by arranging for the decrementer to contain a value no greater than the number of timebase ticks remaining until the end of the timeslice. In the case of a thread with no vcpu, this number is in the hypervisor decrementer already. In the case of a ceded vcpu, we use the smaller of the HDEC value and the DEC value. Using the DEC like this when ceded means we need to save and restore the guest decrementer value around the nap. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:08 +08:00
/* put the HDEC into the DEC, since HDEC interrupts don't wake us */
mfspr r3, SPRN_HDEC
mtspr SPRN_DEC, r3
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
/*
* Make sure the primary has finished the MMU switch.
* We should never get here on a secondary thread, but
* check it for robustness' sake.
*/
ld r5, HSTATE_KVM_VCORE(r13)
65: lbz r0, VCORE_IN_GUEST(r5)
cmpwi r0, 0
beq 65b
/* Set LPCR. */
ld r8,VCORE_LPCR(r5)
mtspr SPRN_LPCR,r8
isync
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* set our bit in napping_threads */
ld r5, HSTATE_KVM_VCORE(r13)
lbz r7, HSTATE_PTID(r13)
li r0, 1
sld r0, r0, r7
addi r6, r5, VCORE_NAPPING_THREADS
1: lwarx r3, 0, r6
or r3, r3, r0
stwcx. r3, 0, r6
bne 1b
KVM: PPC: Book3S HV: Use bitmap of active threads rather than count Currently, the entry_exit_count field in the kvmppc_vcore struct contains two 8-bit counts, one of the threads that have started entering the guest, and one of the threads that have started exiting the guest. This changes it to an entry_exit_map field which contains two bitmaps of 8 bits each. The advantage of doing this is that it gives us a bitmap of which threads need to be signalled when exiting the guest. That means that we no longer need to use the trick of setting the HDEC to 0 to pull the other threads out of the guest, which led in some cases to a spurious HDEC interrupt on the next guest entry. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:09 +08:00
/* order napping_threads update vs testing entry_exit_map */
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
isync
li r12, 0
lwz r7, VCORE_ENTRY_EXIT(r5)
cmpwi r7, 0x100
bge kvm_novcpu_exit /* another thread already exiting */
li r3, NAPPING_NOVCPU
stb r3, HSTATE_NAPPING(r13)
KVM: PPC: Book3S HV: Don't wake thread with no vcpu on guest IPI When running a multi-threaded guest and vcpu 0 in a virtual core is not running in the guest (i.e. it is busy elsewhere in the host), thread 0 of the physical core will switch the MMU to the guest and then go to nap mode in the code at kvm_do_nap. If the guest sends an IPI to thread 0 using the msgsndp instruction, that will wake up thread 0 and cause all the threads in the guest to exit to the host unnecessarily. To avoid the unnecessary exit, this arranges for the PECEDP bit to be cleared in this situation. When napping due to a H_CEDE from the guest, we still set PECEDP so that the thread will wake up on an IPI sent using msgsndp. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:07 +08:00
li r3, 0 /* Don't wake on privileged (OS) doorbell */
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
b kvm_do_nap
kvm_novcpu_wakeup:
ld r1, HSTATE_HOST_R1(r13)
ld r5, HSTATE_KVM_VCORE(r13)
li r0, 0
stb r0, HSTATE_NAPPING(r13)
stb r0, HSTATE_HWTHREAD_REQ(r13)
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
/* check the wake reason */
bl kvmppc_check_wake_reason
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* see if any other thread is already exiting */
lwz r0, VCORE_ENTRY_EXIT(r5)
cmpwi r0, 0x100
bge kvm_novcpu_exit
/* clear our bit in napping_threads */
lbz r7, HSTATE_PTID(r13)
li r0, 1
sld r0, r0, r7
addi r6, r5, VCORE_NAPPING_THREADS
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
4: lwarx r7, 0, r6
andc r7, r7, r0
stwcx. r7, 0, r6
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
bne 4b
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
/* See if the wake reason means we need to exit */
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
cmpdi r3, 0
bge kvm_novcpu_exit
KVM: PPC: Book3S HV: Use decrementer to wake napping threads This arranges for threads that are napping due to their vcpu having ceded or due to not having a vcpu to wake up at the end of the guest's timeslice without having to be poked with an IPI. We do that by arranging for the decrementer to contain a value no greater than the number of timebase ticks remaining until the end of the timeslice. In the case of a thread with no vcpu, this number is in the hypervisor decrementer already. In the case of a ceded vcpu, we use the smaller of the HDEC value and the DEC value. Using the DEC like this when ceded means we need to save and restore the guest decrementer value around the nap. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:08 +08:00
/* See if our timeslice has expired (HDEC is negative) */
mfspr r0, SPRN_HDEC
li r12, BOOK3S_INTERRUPT_HV_DECREMENTER
cmpwi r0, 0
blt kvm_novcpu_exit
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Got an IPI but other vcpus aren't yet exiting, must be a latecomer */
ld r4, HSTATE_KVM_VCPU(r13)
cmpdi r4, 0
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
beq kvmppc_primary_no_guest
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
addi r3, r4, VCPU_TB_RMENTRY
bl kvmhv_start_timing
#endif
b kvmppc_got_guest
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
kvm_novcpu_exit:
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
ld r4, HSTATE_KVM_VCPU(r13)
cmpdi r4, 0
beq 13f
addi r3, r4, VCPU_TB_RMEXIT
bl kvmhv_accumulate_time
#endif
KVM: PPC: Book3S HV: Translate kvmhv_commence_exit to C This replaces the assembler code for kvmhv_commence_exit() with C code in book3s_hv_builtin.c. It also moves the IPI sending code that was in book3s_hv_rm_xics.c into a new kvmhv_rm_send_ipi() function so it can be used by kvmhv_commence_exit() as well as icp_rm_set_vcpu_irq(). Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:11 +08:00
13: mr r3, r12
stw r12, 112-4(r1)
bl kvmhv_commence_exit
nop
lwz r12, 112-4(r1)
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
b kvmhv_switch_to_host
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
/*
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
* We come in here when wakened from nap mode.
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
* Relocation is off and most register values are lost.
* r13 points to the PACA.
*/
.globl kvm_start_guest
kvm_start_guest:
ppc/kvm: Set the runlatch bit of a CPU just before starting guest The secondary threads in the core are kept offline before launching guests in kvm on powerpc: "371fefd6f2dc4666:KVM: PPC: Allow book3s_hv guests to use SMT processor modes." Hence their runlatch bits are cleared. When the secondary threads are called in to start a guest, their runlatch bits need to be set to indicate that they are busy. The primary thread has its runlatch bit set though, but there is no harm in setting this bit once again. Hence set the runlatch bit for all threads before they start guest. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-11 18:31:58 +08:00
/* Set runlatch bit the minute you wake up from nap */
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
mfspr r0, SPRN_CTRLF
ori r0, r0, 1
mtspr SPRN_CTRLT, r0
ppc/kvm: Set the runlatch bit of a CPU just before starting guest The secondary threads in the core are kept offline before launching guests in kvm on powerpc: "371fefd6f2dc4666:KVM: PPC: Allow book3s_hv guests to use SMT processor modes." Hence their runlatch bits are cleared. When the secondary threads are called in to start a guest, their runlatch bits need to be set to indicate that they are busy. The primary thread has its runlatch bit set though, but there is no harm in setting this bit once again. Hence set the runlatch bit for all threads before they start guest. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-11 18:31:58 +08:00
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
ld r2,PACATOC(r13)
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
li r0,KVM_HWTHREAD_IN_KVM
stb r0,HSTATE_HWTHREAD_STATE(r13)
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
/* NV GPR values from power7_idle() will no longer be valid */
li r0,1
stb r0,PACA_NAPSTATELOST(r13)
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
/* were we napping due to cede? */
lbz r0,HSTATE_NAPPING(r13)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
cmpwi r0,NAPPING_CEDE
beq kvm_end_cede
cmpwi r0,NAPPING_NOVCPU
beq kvm_novcpu_wakeup
ld r1,PACAEMERGSP(r13)
subi r1,r1,STACK_FRAME_OVERHEAD
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
/*
* We weren't napping due to cede, so this must be a secondary
* thread being woken up to run a guest, or being woken up due
* to a stray IPI. (Or due to some machine check or hypervisor
* maintenance interrupt while the core is in KVM.)
*/
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
/* Check the wake reason in SRR1 to see why we got here */
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
bl kvmppc_check_wake_reason
cmpdi r3, 0
bge kvm_no_guest
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
/* get vcpu pointer, NULL if we have no vcpu to run */
KVM: PPC: Book3S HV: Fix some races in starting secondary threads Subsequent patches implementing in-kernel XICS emulation will make it possible for IPIs to arrive at secondary threads at arbitrary times. This fixes some races in how we start the secondary threads, which if not fixed could lead to occasional crashes of the host kernel. This makes sure that (a) we have grabbed all the secondary threads, and verified that they are no longer in the kernel, before we start any thread, (b) that the secondary thread loads its vcpu pointer after clearing the IPI that woke it up (so we don't miss a wakeup), and (c) that the secondary thread clears its vcpu pointer before incrementing the nap count. It also removes unnecessary setting of the vcpu and vcore pointers in the paca in kvmppc_core_vcpu_load. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-10-15 09:16:14 +08:00
ld r4,HSTATE_KVM_VCPU(r13)
cmpdi r4,0
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
/* if we have no vcpu to run, go back to sleep */
KVM: PPC: Book3S HV: Fix some races in starting secondary threads Subsequent patches implementing in-kernel XICS emulation will make it possible for IPIs to arrive at secondary threads at arbitrary times. This fixes some races in how we start the secondary threads, which if not fixed could lead to occasional crashes of the host kernel. This makes sure that (a) we have grabbed all the secondary threads, and verified that they are no longer in the kernel, before we start any thread, (b) that the secondary thread loads its vcpu pointer after clearing the IPI that woke it up (so we don't miss a wakeup), and (c) that the secondary thread clears its vcpu pointer before incrementing the nap count. It also removes unnecessary setting of the vcpu and vcore pointers in the paca in kvmppc_core_vcpu_load. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-10-15 09:16:14 +08:00
beq kvm_no_guest
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
powerpc/powernv: Return to cpu offline loop when finished in KVM guest When a secondary hardware thread has finished running a KVM guest, we currently put that thread into nap mode using a nap instruction in the KVM code. This changes the code so that instead of doing a nap instruction directly, we instead cause the call to power7_nap() that put the thread into nap mode to return. The reason for doing this is to avoid having the KVM code having to know what low-power mode to put the thread into. In the case of a secondary thread used to run a KVM guest, the thread will be offline from the point of view of the host kernel, and the relevant power7_nap() call is the one in pnv_smp_cpu_disable(). In this case we don't want to clear pending IPIs in the offline loop in that function, since that might cause us to miss the wakeup for the next time the thread needs to run a guest. To tell whether or not to clear the interrupt, we use the SRR1 value returned from power7_nap(), and check if it indicates an external interrupt. We arrange that the return from power7_nap() when we have finished running a guest returns 0, so pending interrupts don't get flushed in that case. Note that it is important a secondary thread that has finished executing in the guest, or that didn't have a guest to run, should not return to power7_nap's caller while the kvm_hstate.hwthread_req flag in the PACA is non-zero, because the return from power7_nap will reenable the MMU, and the MMU might still be in guest context. In this situation we spin at low priority in real mode waiting for hwthread_req to become zero. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-03 11:48:40 +08:00
kvm_secondary_got_guest:
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Set HSTATE_DSCR(r13) to something sensible */
powerpc/kernel: Rename PACA_DSCR to PACA_DSCR_DEFAULT PACA_DSCR offset macro tracks dscr_default element in the paca structure. Better change the name of this macro to match that of the data element it tracks. Makes the code more readable. Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2015-05-21 14:43:03 +08:00
ld r6, PACA_DSCR_DEFAULT(r13)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
std r6, HSTATE_DSCR(r13)
powerpc: Provide a way for KVM to indicate that NV GPR values are lost This fixes a problem where a CPU thread coming out of nap mode can think it has valid values in the nonvolatile GPRs (r14 - r31) as saved away in power7_idle, but in fact the values have been trashed because the thread was used for KVM in the mean time. The result is that the thread crashes because code that called power7_idle (e.g., pnv_smp_cpu_kill_self()) goes to use values in registers that have been trashed. The bit field in SRR1 that tells whether state was lost only reflects the most recent nap, which may not have been the nap instruction in power7_idle. So we need an extra PACA field to indicate that state has been lost even if SRR1 indicates that the most recent nap didn't lose state. We clear this field when saving the state in power7_idle, we set it to a non-zero value when we use the thread for KVM, and we test it in power7_wakeup_noloss. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-06 03:47:26 +08:00
KVM: PPC: Book3S HV: Get rid of vcore nap_count and n_woken We can tell when a secondary thread has finished running a guest by the fact that it clears its kvm_hstate.kvm_vcpu pointer, so there is no real need for the nap_count field in the kvmppc_vcore struct. This changes kvmppc_wait_for_nap to poll the kvm_hstate.kvm_vcpu pointers of the secondary threads rather than polling vc->nap_count. Besides reducing the size of the kvmppc_vcore struct by 8 bytes, this also means that we can tell which secondary threads have got stuck and thus print a more informative error message. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:06 +08:00
/* Order load of vcore, ptid etc. after load of vcpu */
lwsync
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
bl kvmppc_hv_entry
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
/* Back from the guest, go back to nap */
/* Clear our vcpu pointer so we don't come back in early */
li r0, 0
KVM: PPC: Book3S HV: Refine barriers in guest entry/exit Some users have reported instances of the host hanging with secondary threads of a core waiting for the primary thread to exit the guest, and the primary thread stuck in nap mode. This prompted a review of the memory barriers in the guest entry/exit code, and this is the result. Most of these changes are the suggestions of Dean Burdick <deanburdick@us.ibm.com>. The barriers between updating napping_threads and reading the entry_exit_count on the one hand, and updating entry_exit_count and reading napping_threads on the other, need to be isync not lwsync, since we need to ensure that either the napping_threads update or the entry_exit_count update get seen. It is not sufficient to order the load vs. lwarx, as lwsync does; we need to order the load vs. the stwcx., so we need isync. In addition, we need a full sync before sending IPIs to wake other threads from nap, to ensure that the write to the entry_exit_count is visible before the IPI occurs. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-16 14:46:03 +08:00
/*
KVM: PPC: Book3S HV: Get rid of vcore nap_count and n_woken We can tell when a secondary thread has finished running a guest by the fact that it clears its kvm_hstate.kvm_vcpu pointer, so there is no real need for the nap_count field in the kvmppc_vcore struct. This changes kvmppc_wait_for_nap to poll the kvm_hstate.kvm_vcpu pointers of the secondary threads rather than polling vc->nap_count. Besides reducing the size of the kvmppc_vcore struct by 8 bytes, this also means that we can tell which secondary threads have got stuck and thus print a more informative error message. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:06 +08:00
* Once we clear HSTATE_KVM_VCPU(r13), the code in
* kvmppc_run_core() is going to assume that all our vcpu
* state is visible in memory. This lwsync makes sure
* that that is true.
KVM: PPC: Book3S HV: Refine barriers in guest entry/exit Some users have reported instances of the host hanging with secondary threads of a core waiting for the primary thread to exit the guest, and the primary thread stuck in nap mode. This prompted a review of the memory barriers in the guest entry/exit code, and this is the result. Most of these changes are the suggestions of Dean Burdick <deanburdick@us.ibm.com>. The barriers between updating napping_threads and reading the entry_exit_count on the one hand, and updating entry_exit_count and reading napping_threads on the other, need to be isync not lwsync, since we need to ensure that either the napping_threads update or the entry_exit_count update get seen. It is not sufficient to order the load vs. lwarx, as lwsync does; we need to order the load vs. the stwcx., so we need isync. In addition, we need a full sync before sending IPIs to wake other threads from nap, to ensure that the write to the entry_exit_count is visible before the IPI occurs. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-16 14:46:03 +08:00
*/
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
lwsync
KVM: PPC: Book3S HV: Get rid of vcore nap_count and n_woken We can tell when a secondary thread has finished running a guest by the fact that it clears its kvm_hstate.kvm_vcpu pointer, so there is no real need for the nap_count field in the kvmppc_vcore struct. This changes kvmppc_wait_for_nap to poll the kvm_hstate.kvm_vcpu pointers of the secondary threads rather than polling vc->nap_count. Besides reducing the size of the kvmppc_vcore struct by 8 bytes, this also means that we can tell which secondary threads have got stuck and thus print a more informative error message. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:06 +08:00
std r0, HSTATE_KVM_VCPU(r13)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
powerpc/powernv: Return to cpu offline loop when finished in KVM guest When a secondary hardware thread has finished running a KVM guest, we currently put that thread into nap mode using a nap instruction in the KVM code. This changes the code so that instead of doing a nap instruction directly, we instead cause the call to power7_nap() that put the thread into nap mode to return. The reason for doing this is to avoid having the KVM code having to know what low-power mode to put the thread into. In the case of a secondary thread used to run a KVM guest, the thread will be offline from the point of view of the host kernel, and the relevant power7_nap() call is the one in pnv_smp_cpu_disable(). In this case we don't want to clear pending IPIs in the offline loop in that function, since that might cause us to miss the wakeup for the next time the thread needs to run a guest. To tell whether or not to clear the interrupt, we use the SRR1 value returned from power7_nap(), and check if it indicates an external interrupt. We arrange that the return from power7_nap() when we have finished running a guest returns 0, so pending interrupts don't get flushed in that case. Note that it is important a secondary thread that has finished executing in the guest, or that didn't have a guest to run, should not return to power7_nap's caller while the kvm_hstate.hwthread_req flag in the PACA is non-zero, because the return from power7_nap will reenable the MMU, and the MMU might still be in guest context. In this situation we spin at low priority in real mode waiting for hwthread_req to become zero. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-03 11:48:40 +08:00
/*
* At this point we have finished executing in the guest.
* We need to wait for hwthread_req to become zero, since
* we may not turn on the MMU while hwthread_req is non-zero.
* While waiting we also need to check if we get given a vcpu to run.
*/
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
kvm_no_guest:
powerpc/powernv: Return to cpu offline loop when finished in KVM guest When a secondary hardware thread has finished running a KVM guest, we currently put that thread into nap mode using a nap instruction in the KVM code. This changes the code so that instead of doing a nap instruction directly, we instead cause the call to power7_nap() that put the thread into nap mode to return. The reason for doing this is to avoid having the KVM code having to know what low-power mode to put the thread into. In the case of a secondary thread used to run a KVM guest, the thread will be offline from the point of view of the host kernel, and the relevant power7_nap() call is the one in pnv_smp_cpu_disable(). In this case we don't want to clear pending IPIs in the offline loop in that function, since that might cause us to miss the wakeup for the next time the thread needs to run a guest. To tell whether or not to clear the interrupt, we use the SRR1 value returned from power7_nap(), and check if it indicates an external interrupt. We arrange that the return from power7_nap() when we have finished running a guest returns 0, so pending interrupts don't get flushed in that case. Note that it is important a secondary thread that has finished executing in the guest, or that didn't have a guest to run, should not return to power7_nap's caller while the kvm_hstate.hwthread_req flag in the PACA is non-zero, because the return from power7_nap will reenable the MMU, and the MMU might still be in guest context. In this situation we spin at low priority in real mode waiting for hwthread_req to become zero. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-03 11:48:40 +08:00
lbz r3, HSTATE_HWTHREAD_REQ(r13)
cmpwi r3, 0
bne 53f
HMT_MEDIUM
li r0, KVM_HWTHREAD_IN_KERNEL
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
stb r0, HSTATE_HWTHREAD_STATE(r13)
powerpc/powernv: Return to cpu offline loop when finished in KVM guest When a secondary hardware thread has finished running a KVM guest, we currently put that thread into nap mode using a nap instruction in the KVM code. This changes the code so that instead of doing a nap instruction directly, we instead cause the call to power7_nap() that put the thread into nap mode to return. The reason for doing this is to avoid having the KVM code having to know what low-power mode to put the thread into. In the case of a secondary thread used to run a KVM guest, the thread will be offline from the point of view of the host kernel, and the relevant power7_nap() call is the one in pnv_smp_cpu_disable(). In this case we don't want to clear pending IPIs in the offline loop in that function, since that might cause us to miss the wakeup for the next time the thread needs to run a guest. To tell whether or not to clear the interrupt, we use the SRR1 value returned from power7_nap(), and check if it indicates an external interrupt. We arrange that the return from power7_nap() when we have finished running a guest returns 0, so pending interrupts don't get flushed in that case. Note that it is important a secondary thread that has finished executing in the guest, or that didn't have a guest to run, should not return to power7_nap's caller while the kvm_hstate.hwthread_req flag in the PACA is non-zero, because the return from power7_nap will reenable the MMU, and the MMU might still be in guest context. In this situation we spin at low priority in real mode waiting for hwthread_req to become zero. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-03 11:48:40 +08:00
/* need to recheck hwthread_req after a barrier, to avoid race */
sync
lbz r3, HSTATE_HWTHREAD_REQ(r13)
cmpwi r3, 0
bne 54f
/*
* We jump to power7_wakeup_loss, which will return to the caller
* of power7_nap in the powernv cpu offline loop. The value we
* put in r3 becomes the return value for power7_nap.
*/
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
li r3, LPCR_PECE0
mfspr r4, SPRN_LPCR
rlwimi r4, r3, 0, LPCR_PECE0 | LPCR_PECE1
mtspr SPRN_LPCR, r4
powerpc/powernv: Return to cpu offline loop when finished in KVM guest When a secondary hardware thread has finished running a KVM guest, we currently put that thread into nap mode using a nap instruction in the KVM code. This changes the code so that instead of doing a nap instruction directly, we instead cause the call to power7_nap() that put the thread into nap mode to return. The reason for doing this is to avoid having the KVM code having to know what low-power mode to put the thread into. In the case of a secondary thread used to run a KVM guest, the thread will be offline from the point of view of the host kernel, and the relevant power7_nap() call is the one in pnv_smp_cpu_disable(). In this case we don't want to clear pending IPIs in the offline loop in that function, since that might cause us to miss the wakeup for the next time the thread needs to run a guest. To tell whether or not to clear the interrupt, we use the SRR1 value returned from power7_nap(), and check if it indicates an external interrupt. We arrange that the return from power7_nap() when we have finished running a guest returns 0, so pending interrupts don't get flushed in that case. Note that it is important a secondary thread that has finished executing in the guest, or that didn't have a guest to run, should not return to power7_nap's caller while the kvm_hstate.hwthread_req flag in the PACA is non-zero, because the return from power7_nap will reenable the MMU, and the MMU might still be in guest context. In this situation we spin at low priority in real mode waiting for hwthread_req to become zero. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-03 11:48:40 +08:00
li r3, 0
b power7_wakeup_loss
53: HMT_LOW
ld r4, HSTATE_KVM_VCPU(r13)
cmpdi r4, 0
beq kvm_no_guest
HMT_MEDIUM
b kvm_secondary_got_guest
54: li r0, KVM_HWTHREAD_IN_KVM
stb r0, HSTATE_HWTHREAD_STATE(r13)
b kvm_no_guest
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
/******************************************************************************
* *
* Entry code *
* *
*****************************************************************************/
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
.global kvmppc_hv_entry
kvmppc_hv_entry:
/* Required state:
*
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
* R4 = vcpu pointer (or NULL)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
* MSR = ~IR|DR
* R13 = PACA
* R1 = host R1
KVM: PPC: Book3S HV: Add register name when loading toc Add 'r' to register name r2 in kvmppc_hv_enter. Also update comment at the top of kvmppc_hv_enter to indicate that R2/TOC is non-volatile. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-08-19 12:59:30 +08:00
* R2 = TOC
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
* all other volatile GPRS = free
*/
mflr r0
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
std r0, PPC_LR_STKOFF(r1)
stdu r1, -112(r1)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Save R1 in the PACA */
std r1, HSTATE_HOST_R1(r13)
KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode When an interrupt or exception happens in the guest that comes to the host, the CPU goes to hypervisor real mode (MMU off) to handle the exception but doesn't change the MMU context. After saving a few registers, we then clear the "in guest" flag. If, for any reason, we get an exception in the real-mode code, that then gets handled by the normal kernel exception handlers, which turn the MMU on. This is disastrous if the MMU is still set to the guest context, since we end up executing instructions from random places in the guest kernel with hypervisor privilege. In order to catch this situation, we define a new value for the "in guest" flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real mode with guest MMU context. If the "in guest" flag is set to this value, we branch off to an emergency handler. For the moment, this just does a branch to self to stop the CPU from doing anything further. While we're here, we define another new flag value to indicate that we are in a HV guest, as distinct from a PR guest. This will be useful when we have a kernel that can support both PR and HV guests concurrently. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-04 19:45:04 +08:00
li r6, KVM_GUEST_MODE_HOST_HV
stb r6, HSTATE_IN_GUEST(r13)
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
/* Store initial timestamp */
cmpdi r4, 0
beq 1f
addi r3, r4, VCPU_TB_RMENTRY
bl kvmhv_start_timing
1:
#endif
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Clear out SLB */
li r6,0
slbmte r6,r6
slbia
ptesync
KVM: PPC: book3s_hv: Add support for PPC970-family processors This adds support for running KVM guests in supervisor mode on those PPC970 processors that have a usable hypervisor mode. Unfortunately, Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to 1), but the YDL PowerStation does have a usable hypervisor mode. There are several differences between the PPC970 and POWER7 in how guests are managed. These differences are accommodated using the CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature bits. Notably, on PPC970: * The LPCR, LPID or RMOR registers don't exist, and the functions of those registers are provided by bits in HID4 and one bit in HID0. * External interrupts can be directed to the hypervisor, but unlike POWER7 they are masked by MSR[EE] in non-hypervisor modes and use SRR0/1 not HSRR0/1. * There is no virtual RMA (VRMA) mode; the guest must use an RMO (real mode offset) area. * The TLB entries are not tagged with the LPID, so it is necessary to flush the whole TLB on partition switch. Furthermore, when switching partitions we have to ensure that no other CPU is executing the tlbie or tlbsync instructions in either the old or the new partition, otherwise undefined behaviour can occur. * The PMU has 8 counters (PMC registers) rather than 6. * The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist. * The SLB has 64 entries rather than 32. * There is no mediated external interrupt facility, so if we switch to a guest that has a virtual external interrupt pending but the guest has MSR[EE] = 0, we have to arrange to have an interrupt pending for it so that we can get control back once it re-enables interrupts. We do that by sending ourselves an IPI with smp_send_reschedule after hard-disabling interrupts. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:40:08 +08:00
/*
KVM: PPC: Book3S HV: Remove code for PPC970 processors This removes the code that was added to enable HV KVM to work on PPC970 processors. The PPC970 is an old CPU that doesn't support virtualizing guest memory. Removing PPC970 support also lets us remove the code for allocating and managing contiguous real-mode areas, the code for the !kvm->arch.using_mmu_notifiers case, the code for pinning pages of guest memory when first accessed and keeping track of which pages have been pinned, and the code for handling H_ENTER hypercalls in virtual mode. Book3S HV KVM is now supported only on POWER7 and POWER8 processors. The KVM_CAP_PPC_RMA capability now always returns 0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:38 +08:00
* POWER7/POWER8 host -> guest partition switch code.
KVM: PPC: book3s_hv: Add support for PPC970-family processors This adds support for running KVM guests in supervisor mode on those PPC970 processors that have a usable hypervisor mode. Unfortunately, Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to 1), but the YDL PowerStation does have a usable hypervisor mode. There are several differences between the PPC970 and POWER7 in how guests are managed. These differences are accommodated using the CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature bits. Notably, on PPC970: * The LPCR, LPID or RMOR registers don't exist, and the functions of those registers are provided by bits in HID4 and one bit in HID0. * External interrupts can be directed to the hypervisor, but unlike POWER7 they are masked by MSR[EE] in non-hypervisor modes and use SRR0/1 not HSRR0/1. * There is no virtual RMA (VRMA) mode; the guest must use an RMO (real mode offset) area. * The TLB entries are not tagged with the LPID, so it is necessary to flush the whole TLB on partition switch. Furthermore, when switching partitions we have to ensure that no other CPU is executing the tlbie or tlbsync instructions in either the old or the new partition, otherwise undefined behaviour can occur. * The PMU has 8 counters (PMC registers) rather than 6. * The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist. * The SLB has 64 entries rather than 32. * There is no mediated external interrupt facility, so if we switch to a guest that has a virtual external interrupt pending but the guest has MSR[EE] = 0, we have to arrange to have an interrupt pending for it so that we can get control back once it re-enables interrupts. We do that by sending ourselves an IPI with smp_send_reschedule after hard-disabling interrupts. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:40:08 +08:00
* We don't have to lock against concurrent tlbies,
* but we do have to coordinate across hardware threads.
*/
KVM: PPC: Book3S HV: Use bitmap of active threads rather than count Currently, the entry_exit_count field in the kvmppc_vcore struct contains two 8-bit counts, one of the threads that have started entering the guest, and one of the threads that have started exiting the guest. This changes it to an entry_exit_map field which contains two bitmaps of 8 bits each. The advantage of doing this is that it gives us a bitmap of which threads need to be signalled when exiting the guest. That means that we no longer need to use the trick of setting the HDEC to 0 to pull the other threads out of the guest, which led in some cases to a spurious HDEC interrupt on the next guest entry. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:09 +08:00
/* Set bit in entry map iff exit map is zero. */
ld r5, HSTATE_KVM_VCORE(r13)
li r7, 1
lbz r6, HSTATE_PTID(r13)
sld r7, r7, r6
addi r9, r5, VCORE_ENTRY_EXIT
21: lwarx r3, 0, r9
cmpwi r3, 0x100 /* any threads starting to exit? */
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
bge secondary_too_late /* if so we're too late to the party */
KVM: PPC: Book3S HV: Use bitmap of active threads rather than count Currently, the entry_exit_count field in the kvmppc_vcore struct contains two 8-bit counts, one of the threads that have started entering the guest, and one of the threads that have started exiting the guest. This changes it to an entry_exit_map field which contains two bitmaps of 8 bits each. The advantage of doing this is that it gives us a bitmap of which threads need to be signalled when exiting the guest. That means that we no longer need to use the trick of setting the HDEC to 0 to pull the other threads out of the guest, which led in some cases to a spurious HDEC interrupt on the next guest entry. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:09 +08:00
or r3, r3, r7
stwcx. r3, 0, r9
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
bne 21b
/* Primary thread switches to guest partition. */
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
ld r9,VCORE_KVM(r5) /* pointer to struct kvm */
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
cmpwi r6,0
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
bne 10f
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
ld r6,KVM_SDR1(r9)
lwz r7,KVM_LPID(r9)
li r0,LPID_RSVD /* switch to reserved LPID */
mtspr SPRN_LPID,r0
ptesync
mtspr SPRN_SDR1,r6 /* switch to partition page table */
mtspr SPRN_LPID,r7
isync
KVM: PPC: Book3S HV: Improve handling of local vs. global TLB invalidations When we change or remove a HPT (hashed page table) entry, we can do either a global TLB invalidation (tlbie) that works across the whole machine, or a local invalidation (tlbiel) that only affects this core. Currently we do local invalidations if the VM has only one vcpu or if the guest requests it with the H_LOCAL flag, though the guest Linux kernel currently doesn't ever use H_LOCAL. Then, to cope with the possibility that vcpus moving around to different physical cores might expose stale TLB entries, there is some code in kvmppc_hv_entry to flush the whole TLB of entries for this VM if either this vcpu is now running on a different physical core from where it last ran, or if this physical core last ran a different vcpu. There are a number of problems on POWER7 with this as it stands: - The TLB invalidation is done per thread, whereas it only needs to be done per core, since the TLB is shared between the threads. - With the possibility of the host paging out guest pages, the use of H_LOCAL by an SMP guest is dangerous since the guest could possibly retain and use a stale TLB entry pointing to a page that had been removed from the guest. - The TLB invalidations that we do when a vcpu moves from one physical core to another are unnecessary in the case of an SMP guest that isn't using H_LOCAL. - The optimization of using local invalidations rather than global should apply to guests with one virtual core, not just one vcpu. (None of this applies on PPC970, since there we always have to invalidate the whole TLB when entering and leaving the guest, and we can't support paging out guest memory.) To fix these problems and simplify the code, we now maintain a simple cpumask of which cpus need to flush the TLB on entry to the guest. (This is indexed by cpu, though we only ever use the bits for thread 0 of each core.) Whenever we do a local TLB invalidation, we set the bits for every cpu except the bit for thread 0 of the core that we're currently running on. Whenever we enter a guest, we test and clear the bit for our core, and flush the TLB if it was set. On initial startup of the VM, and when resetting the HPT, we set all the bits in the need_tlb_flush cpumask, since any core could potentially have stale TLB entries from the previous VM to use the same LPID, or the previous contents of the HPT. Then, we maintain a count of the number of online virtual cores, and use that when deciding whether to use a local invalidation rather than the number of online vcpus. The code to make that decision is extracted out into a new function, global_invalidates(). For multi-core guests on POWER7 (i.e. when we are using mmu notifiers), we now never do local invalidations regardless of the H_LOCAL flag. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-22 07:28:08 +08:00
/* See if we need to flush the TLB */
lhz r6,PACAPACAINDEX(r13) /* test_bit(cpu, need_tlb_flush) */
clrldi r7,r6,64-6 /* extract bit number (6 bits) */
srdi r6,r6,6 /* doubleword number */
sldi r6,r6,3 /* address offset */
add r6,r6,r9
addi r6,r6,KVM_NEED_FLUSH /* dword in kvm->arch.need_tlb_flush */
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
li r0,1
KVM: PPC: Book3S HV: Improve handling of local vs. global TLB invalidations When we change or remove a HPT (hashed page table) entry, we can do either a global TLB invalidation (tlbie) that works across the whole machine, or a local invalidation (tlbiel) that only affects this core. Currently we do local invalidations if the VM has only one vcpu or if the guest requests it with the H_LOCAL flag, though the guest Linux kernel currently doesn't ever use H_LOCAL. Then, to cope with the possibility that vcpus moving around to different physical cores might expose stale TLB entries, there is some code in kvmppc_hv_entry to flush the whole TLB of entries for this VM if either this vcpu is now running on a different physical core from where it last ran, or if this physical core last ran a different vcpu. There are a number of problems on POWER7 with this as it stands: - The TLB invalidation is done per thread, whereas it only needs to be done per core, since the TLB is shared between the threads. - With the possibility of the host paging out guest pages, the use of H_LOCAL by an SMP guest is dangerous since the guest could possibly retain and use a stale TLB entry pointing to a page that had been removed from the guest. - The TLB invalidations that we do when a vcpu moves from one physical core to another are unnecessary in the case of an SMP guest that isn't using H_LOCAL. - The optimization of using local invalidations rather than global should apply to guests with one virtual core, not just one vcpu. (None of this applies on PPC970, since there we always have to invalidate the whole TLB when entering and leaving the guest, and we can't support paging out guest memory.) To fix these problems and simplify the code, we now maintain a simple cpumask of which cpus need to flush the TLB on entry to the guest. (This is indexed by cpu, though we only ever use the bits for thread 0 of each core.) Whenever we do a local TLB invalidation, we set the bits for every cpu except the bit for thread 0 of the core that we're currently running on. Whenever we enter a guest, we test and clear the bit for our core, and flush the TLB if it was set. On initial startup of the VM, and when resetting the HPT, we set all the bits in the need_tlb_flush cpumask, since any core could potentially have stale TLB entries from the previous VM to use the same LPID, or the previous contents of the HPT. Then, we maintain a count of the number of online virtual cores, and use that when deciding whether to use a local invalidation rather than the number of online vcpus. The code to make that decision is extracted out into a new function, global_invalidates(). For multi-core guests on POWER7 (i.e. when we are using mmu notifiers), we now never do local invalidations regardless of the H_LOCAL flag. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-22 07:28:08 +08:00
sld r0,r0,r7
ld r7,0(r6)
and. r7,r7,r0
beq 22f
23: ldarx r7,0,r6 /* if set, clear the bit */
andc r7,r7,r0
stdcx. r7,0,r6
bne 23b
KVM: PPC: Book3S HV: Flush the correct number of TLB sets on POWER8 POWER8 has 512 sets in the TLB, compared to 128 for POWER7, so we need to do more tlbiel instructions when flushing the TLB on POWER8. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:22 +08:00
/* Flush the TLB of any entries for this LPID */
/* use arch 2.07S as a proxy for POWER8 */
BEGIN_FTR_SECTION
li r6,512 /* POWER8 has 512 sets */
FTR_SECTION_ELSE
li r6,128 /* POWER7 has 128 sets */
ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Improve handling of local vs. global TLB invalidations When we change or remove a HPT (hashed page table) entry, we can do either a global TLB invalidation (tlbie) that works across the whole machine, or a local invalidation (tlbiel) that only affects this core. Currently we do local invalidations if the VM has only one vcpu or if the guest requests it with the H_LOCAL flag, though the guest Linux kernel currently doesn't ever use H_LOCAL. Then, to cope with the possibility that vcpus moving around to different physical cores might expose stale TLB entries, there is some code in kvmppc_hv_entry to flush the whole TLB of entries for this VM if either this vcpu is now running on a different physical core from where it last ran, or if this physical core last ran a different vcpu. There are a number of problems on POWER7 with this as it stands: - The TLB invalidation is done per thread, whereas it only needs to be done per core, since the TLB is shared between the threads. - With the possibility of the host paging out guest pages, the use of H_LOCAL by an SMP guest is dangerous since the guest could possibly retain and use a stale TLB entry pointing to a page that had been removed from the guest. - The TLB invalidations that we do when a vcpu moves from one physical core to another are unnecessary in the case of an SMP guest that isn't using H_LOCAL. - The optimization of using local invalidations rather than global should apply to guests with one virtual core, not just one vcpu. (None of this applies on PPC970, since there we always have to invalidate the whole TLB when entering and leaving the guest, and we can't support paging out guest memory.) To fix these problems and simplify the code, we now maintain a simple cpumask of which cpus need to flush the TLB on entry to the guest. (This is indexed by cpu, though we only ever use the bits for thread 0 of each core.) Whenever we do a local TLB invalidation, we set the bits for every cpu except the bit for thread 0 of the core that we're currently running on. Whenever we enter a guest, we test and clear the bit for our core, and flush the TLB if it was set. On initial startup of the VM, and when resetting the HPT, we set all the bits in the need_tlb_flush cpumask, since any core could potentially have stale TLB entries from the previous VM to use the same LPID, or the previous contents of the HPT. Then, we maintain a count of the number of online virtual cores, and use that when deciding whether to use a local invalidation rather than the number of online vcpus. The code to make that decision is extracted out into a new function, global_invalidates(). For multi-core guests on POWER7 (i.e. when we are using mmu notifiers), we now never do local invalidations regardless of the H_LOCAL flag. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-22 07:28:08 +08:00
mtctr r6
li r7,0x800 /* IS field = 0b10 */
ptesync
28: tlbiel r7
addi r7,r7,0x1000
bdnz 28b
ptesync
KVM: PPC: Book3S HV: Implement timebase offset for guests This allows guests to have a different timebase origin from the host. This is needed for migration, where a guest can migrate from one host to another and the two hosts might have a different timebase origin. However, the timebase seen by the guest must not go backwards, and should go forwards only by a small amount corresponding to the time taken for the migration. Therefore this provides a new per-vcpu value accessed via the one_reg interface using the new KVM_REG_PPC_TB_OFFSET identifier. This value defaults to 0 and is not modified by KVM. On entering the guest, this value is added onto the timebase, and on exiting the guest, it is subtracted from the timebase. This is only supported for recent POWER hardware which has the TBU40 (timebase upper 40 bits) register. Writing to the TBU40 register only alters the upper 40 bits of the timebase, leaving the lower 24 bits unchanged. This provides a way to modify the timebase for guest migration without disturbing the synchronization of the timebase registers across CPU cores. The kernel rounds up the value given to a multiple of 2^24. Timebase values stored in KVM structures (struct kvm_vcpu, struct kvmppc_vcore, etc.) are stored as host timebase values. The timebase values in the dispatch trace log need to be guest timebase values, however, since that is read directly by the guest. This moves the setting of vcpu->arch.dec_expires on guest exit to a point after we have restored the host timebase so that vcpu->arch.dec_expires is a host timebase value. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:17:46 +08:00
/* Add timebase offset onto timebase */
22: ld r8,VCORE_TB_OFFSET(r5)
cmpdi r8,0
beq 37f
mftb r6 /* current host timebase */
add r8,r8,r6
mtspr SPRN_TBU40,r8 /* update upper 40 bits */
mftb r7 /* check if lower 24 bits overflowed */
clrldi r6,r6,40
clrldi r7,r7,40
cmpld r7,r6
bge 37f
addis r8,r8,0x100 /* if so, increment upper 40 bits */
mtspr SPRN_TBU40,r8
KVM: PPC: Book3S HV: Support POWER6 compatibility mode on POWER7 This enables us to use the Processor Compatibility Register (PCR) on POWER7 to put the processor into architecture 2.05 compatibility mode when running a guest. In this mode the new instructions and registers that were introduced on POWER7 are disabled in user mode. This includes all the VSX facilities plus several other instructions such as ldbrx, stdbrx, popcntw, popcntd, etc. To select this mode, we have a new register accessible through the set/get_one_reg interface, called KVM_REG_PPC_ARCH_COMPAT. Setting this to zero gives the full set of capabilities of the processor. Setting it to one of the "logical" PVR values defined in PAPR puts the vcpu into the compatibility mode for the corresponding architecture level. The supported values are: 0x0f000002 Architecture 2.05 (POWER6) 0x0f000003 Architecture 2.06 (POWER7) 0x0f100003 Architecture 2.06+ (POWER7+) Since the PCR is per-core, the architecture compatibility level and the corresponding PCR value are stored in the struct kvmppc_vcore, and are therefore shared between all vcpus in a virtual core. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: squash in fix to add missing break statements and documentation] Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-21 12:35:02 +08:00
/* Load guest PCR value to select appropriate compat mode */
37: ld r7, VCORE_PCR(r5)
cmpdi r7, 0
beq 38f
mtspr SPRN_PCR, r7
38:
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
BEGIN_FTR_SECTION
/* DPDES is shared between threads */
ld r8, VCORE_DPDES(r5)
mtspr SPRN_DPDES, r8
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Support POWER6 compatibility mode on POWER7 This enables us to use the Processor Compatibility Register (PCR) on POWER7 to put the processor into architecture 2.05 compatibility mode when running a guest. In this mode the new instructions and registers that were introduced on POWER7 are disabled in user mode. This includes all the VSX facilities plus several other instructions such as ldbrx, stdbrx, popcntw, popcntd, etc. To select this mode, we have a new register accessible through the set/get_one_reg interface, called KVM_REG_PPC_ARCH_COMPAT. Setting this to zero gives the full set of capabilities of the processor. Setting it to one of the "logical" PVR values defined in PAPR puts the vcpu into the compatibility mode for the corresponding architecture level. The supported values are: 0x0f000002 Architecture 2.05 (POWER6) 0x0f000003 Architecture 2.06 (POWER7) 0x0f100003 Architecture 2.06+ (POWER7+) Since the PCR is per-core, the architecture compatibility level and the corresponding PCR value are stored in the struct kvmppc_vcore, and are therefore shared between all vcpus in a virtual core. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: squash in fix to add missing break statements and documentation] Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-21 12:35:02 +08:00
li r0,1
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
stb r0,VCORE_IN_GUEST(r5) /* signal secondaries to continue */
KVM: PPC: book3s_hv: Add support for PPC970-family processors This adds support for running KVM guests in supervisor mode on those PPC970 processors that have a usable hypervisor mode. Unfortunately, Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to 1), but the YDL PowerStation does have a usable hypervisor mode. There are several differences between the PPC970 and POWER7 in how guests are managed. These differences are accommodated using the CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature bits. Notably, on PPC970: * The LPCR, LPID or RMOR registers don't exist, and the functions of those registers are provided by bits in HID4 and one bit in HID0. * External interrupts can be directed to the hypervisor, but unlike POWER7 they are masked by MSR[EE] in non-hypervisor modes and use SRR0/1 not HSRR0/1. * There is no virtual RMA (VRMA) mode; the guest must use an RMO (real mode offset) area. * The TLB entries are not tagged with the LPID, so it is necessary to flush the whole TLB on partition switch. Furthermore, when switching partitions we have to ensure that no other CPU is executing the tlbie or tlbsync instructions in either the old or the new partition, otherwise undefined behaviour can occur. * The PMU has 8 counters (PMC registers) rather than 6. * The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist. * The SLB has 64 entries rather than 32. * There is no mediated external interrupt facility, so if we switch to a guest that has a virtual external interrupt pending but the guest has MSR[EE] = 0, we have to arrange to have an interrupt pending for it so that we can get control back once it re-enables interrupts. We do that by sending ourselves an IPI with smp_send_reschedule after hard-disabling interrupts. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:40:08 +08:00
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Do we have a guest vcpu to run? */
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
10: cmpdi r4, 0
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
beq kvmppc_primary_no_guest
kvmppc_got_guest:
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Load up guest SLB entries */
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
lwz r5,VCPU_SLB_MAX(r4)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
cmpwi r5,0
beq 9f
mtctr r5
addi r6,r4,VCPU_SLB
1: ld r8,VCPU_SLB_E(r6)
ld r9,VCPU_SLB_V(r6)
slbmte r9,r8
addi r6,r6,VCPU_SLB_SIZE
bdnz 1b
9:
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Increment yield count if they have a VPA */
ld r3, VCPU_VPA(r4)
cmpdi r3, 0
beq 25f
KVM: PPC: Book3S HV: Access host lppaca and shadow slb in BE Some data structures are always stored in big endian. Among those are the LPPACA fields as well as the shadow slb. These structures might be shared with a hypervisor. So whenever we access those fields, make sure we do so in big endian byte order. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-11 16:36:17 +08:00
li r6, LPPACA_YIELDCOUNT
LWZX_BE r5, r3, r6
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
addi r5, r5, 1
KVM: PPC: Book3S HV: Access host lppaca and shadow slb in BE Some data structures are always stored in big endian. Among those are the LPPACA fields as well as the shadow slb. These structures might be shared with a hypervisor. So whenever we access those fields, make sure we do so in big endian byte order. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-11 16:36:17 +08:00
STWX_BE r5, r3, r6
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
li r6, 1
stb r6, VCPU_VPA_DIRTY(r4)
25:
/* Save purr/spurr */
mfspr r5,SPRN_PURR
mfspr r6,SPRN_SPURR
std r5,HSTATE_PURR(r13)
std r6,HSTATE_SPURR(r13)
ld r7,VCPU_PURR(r4)
ld r8,VCPU_SPURR(r4)
mtspr SPRN_PURR,r7
mtspr SPRN_SPURR,r8
BEGIN_FTR_SECTION
/* Set partition DABR */
/* Do this before re-enabling PMU to avoid P7 DABR corruption bug */
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7 The DABRX (DABR extension) register on POWER7 processors provides finer control over which accesses cause a data breakpoint interrupt. It contains 3 bits which indicate whether to enable accesses in user, kernel and hypervisor modes respectively to cause data breakpoint interrupts, plus one bit that enables both real mode and virtual mode accesses to cause interrupts. Currently, KVM sets DABRX to allow both kernel and user accesses to cause interrupts while in the guest. This adds support for the guest to specify other values for DABRX. PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR and DABRX with one call. This adds a real-mode implementation of H_SET_XDABR, which shares most of its code with the existing H_SET_DABR implementation. To support this, we add a per-vcpu field to store the DABRX value plus code to get and set it via the ONE_REG interface. For Linux guests to use this new hcall, userspace needs to add "hcall-xdabr" to the set of strings in the /chosen/hypertas-functions property in the device tree. If userspace does this and then migrates the guest to a host where the kernel doesn't include this patch, then userspace will need to implement H_SET_XDABR by writing the specified DABR value to the DABR using the ONE_REG interface. In that case, the old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should still work correctly, at least for Linux guests, since Linux guests cope with getting data breakpoint interrupts in modes that weren't requested by just ignoring the interrupt, and Linux guests never set DABRX_BTI. The other thing this does is to make H_SET_DABR and H_SET_XDABR work on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but guests running in POWER7 compatibility mode will still use H_SET_[X]DABR. For them, this adds the logic to convert DABR/X values into DAWR/X values on POWER8. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:29 +08:00
lwz r5,VCPU_DABRX(r4)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
ld r6,VCPU_DABR(r4)
mtspr SPRN_DABRX,r5
mtspr SPRN_DABR,r6
isync
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BEGIN_FTR_SECTION
b skip_tm
END_FTR_SECTION_IFCLR(CPU_FTR_TM)
/* Turn on TM/FP/VSX/VMX so we can restore them. */
mfmsr r5
li r6, MSR_TM >> 32
sldi r6, r6, 32
or r5, r5, r6
ori r5, r5, MSR_FP
oris r5, r5, (MSR_VEC | MSR_VSX)@h
mtmsrd r5
/*
* The user may change these outside of a transaction, so they must
* always be context switched.
*/
ld r5, VCPU_TFHAR(r4)
ld r6, VCPU_TFIAR(r4)
ld r7, VCPU_TEXASR(r4)
mtspr SPRN_TFHAR, r5
mtspr SPRN_TFIAR, r6
mtspr SPRN_TEXASR, r7
ld r5, VCPU_MSR(r4)
rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
beq skip_tm /* TM not active in guest */
/* Make sure the failure summary is set, otherwise we'll program check
* when we trechkpt. It's possible that this might have been not set
* on a kvmppc_set_one_reg() call but we shouldn't let this crash the
* host.
*/
oris r7, r7, (TEXASR_FS)@h
mtspr SPRN_TEXASR, r7
/*
* We need to load up the checkpointed state for the guest.
* We need to do this early as it will blow away any GPRs, VSRs and
* some SPRs.
*/
mr r31, r4
addi r3, r31, VCPU_FPRS_TM
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl load_fp_state
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
addi r3, r31, VCPU_VRS_TM
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl load_vr_state
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
mr r4, r31
lwz r7, VCPU_VRSAVE_TM(r4)
mtspr SPRN_VRSAVE, r7
ld r5, VCPU_LR_TM(r4)
lwz r6, VCPU_CR_TM(r4)
ld r7, VCPU_CTR_TM(r4)
ld r8, VCPU_AMR_TM(r4)
ld r9, VCPU_TAR_TM(r4)
mtlr r5
mtcr r6
mtctr r7
mtspr SPRN_AMR, r8
mtspr SPRN_TAR, r9
/*
* Load up PPR and DSCR values but don't put them in the actual SPRs
* till the last moment to avoid running with userspace PPR and DSCR for
* too long.
*/
ld r29, VCPU_DSCR_TM(r4)
ld r30, VCPU_PPR_TM(r4)
std r2, PACATMSCRATCH(r13) /* Save TOC */
/* Clear the MSR RI since r1, r13 are all going to be foobar. */
li r5, 0
mtmsrd r5, 1
/* Load GPRs r0-r28 */
reg = 0
.rept 29
ld reg, VCPU_GPRS_TM(reg)(r31)
reg = reg + 1
.endr
mtspr SPRN_DSCR, r29
mtspr SPRN_PPR, r30
/* Load final GPRs */
ld 29, VCPU_GPRS_TM(29)(r31)
ld 30, VCPU_GPRS_TM(30)(r31)
ld 31, VCPU_GPRS_TM(31)(r31)
/* TM checkpointed state is now setup. All GPRs are now volatile. */
TRECHKPT
/* Now let's get back the state we need. */
HMT_MEDIUM
GET_PACA(r13)
ld r29, HSTATE_DSCR(r13)
mtspr SPRN_DSCR, r29
ld r4, HSTATE_KVM_VCPU(r13)
ld r1, HSTATE_HOST_R1(r13)
ld r2, PACATMSCRATCH(r13)
/* Set the MSR RI since we have our registers back. */
li r5, MSR_RI
mtmsrd r5, 1
skip_tm:
#endif
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Load guest PMU registers */
/* R4 is live here (vcpu pointer) */
li r3, 1
sldi r3, r3, 31 /* MMCR0_FC (freeze counters) bit */
mtspr SPRN_MMCR0, r3 /* freeze all counters, disable ints */
isync
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs This adds workarounds for two hardware bugs in the POWER8 performance monitor unit (PMU), both related to interrupt generation. The effect of these bugs is that PMU interrupts can get lost, leading to tools such as perf reporting fewer counts and samples than they should. The first bug relates to the PMAO (perf. mon. alert occurred) bit in MMCR0; setting it should cause an interrupt, but doesn't. The other bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0. Setting PMAE when a counter is negative and counter negative conditions are enabled to cause alerts should cause an alert, but doesn't. The workaround for the first bug is to create conditions where a counter will overflow, whenever we are about to restore a MMCR0 value that has PMAO set (and PMAO_SYNC clear). The workaround for the second bug is to freeze all counters using MMCR2 before reading MMCR0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-26 17:48:40 +08:00
BEGIN_FTR_SECTION
ld r3, VCPU_MMCR(r4)
andi. r5, r3, MMCR0_PMAO_SYNC | MMCR0_PMAO
cmpwi r5, MMCR0_PMAO
beql kvmppc_fix_pmao
END_FTR_SECTION_IFSET(CPU_FTR_PMAO_BUG)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
lwz r3, VCPU_PMC(r4) /* always load up guest PMU registers */
lwz r5, VCPU_PMC + 4(r4) /* to prevent information leak */
lwz r6, VCPU_PMC + 8(r4)
lwz r7, VCPU_PMC + 12(r4)
lwz r8, VCPU_PMC + 16(r4)
lwz r9, VCPU_PMC + 20(r4)
mtspr SPRN_PMC1, r3
mtspr SPRN_PMC2, r5
mtspr SPRN_PMC3, r6
mtspr SPRN_PMC4, r7
mtspr SPRN_PMC5, r8
mtspr SPRN_PMC6, r9
ld r3, VCPU_MMCR(r4)
ld r5, VCPU_MMCR + 8(r4)
ld r6, VCPU_MMCR + 16(r4)
ld r7, VCPU_SIAR(r4)
ld r8, VCPU_SDAR(r4)
mtspr SPRN_MMCR1, r5
mtspr SPRN_MMCRA, r6
mtspr SPRN_SIAR, r7
mtspr SPRN_SDAR, r8
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
BEGIN_FTR_SECTION
ld r5, VCPU_MMCR + 24(r4)
ld r6, VCPU_SIER(r4)
lwz r7, VCPU_PMC + 24(r4)
lwz r8, VCPU_PMC + 28(r4)
ld r9, VCPU_MMCR + 32(r4)
mtspr SPRN_MMCR2, r5
mtspr SPRN_SIER, r6
mtspr SPRN_SPMC1, r7
mtspr SPRN_SPMC2, r8
mtspr SPRN_MMCRS, r9
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
mtspr SPRN_MMCR0, r3
isync
/* Load up FP, VMX and VSX registers */
bl kvmppc_load_fp
ld r14, VCPU_GPR(R14)(r4)
ld r15, VCPU_GPR(R15)(r4)
ld r16, VCPU_GPR(R16)(r4)
ld r17, VCPU_GPR(R17)(r4)
ld r18, VCPU_GPR(R18)(r4)
ld r19, VCPU_GPR(R19)(r4)
ld r20, VCPU_GPR(R20)(r4)
ld r21, VCPU_GPR(R21)(r4)
ld r22, VCPU_GPR(R22)(r4)
ld r23, VCPU_GPR(R23)(r4)
ld r24, VCPU_GPR(R24)(r4)
ld r25, VCPU_GPR(R25)(r4)
ld r26, VCPU_GPR(R26)(r4)
ld r27, VCPU_GPR(R27)(r4)
ld r28, VCPU_GPR(R28)(r4)
ld r29, VCPU_GPR(R29)(r4)
ld r30, VCPU_GPR(R30)(r4)
ld r31, VCPU_GPR(R31)(r4)
/* Switch DSCR to guest value */
ld r5, VCPU_DSCR(r4)
mtspr SPRN_DSCR, r5
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
BEGIN_FTR_SECTION
KVM: PPC: Book3S HV: Remove code for PPC970 processors This removes the code that was added to enable HV KVM to work on PPC970 processors. The PPC970 is an old CPU that doesn't support virtualizing guest memory. Removing PPC970 support also lets us remove the code for allocating and managing contiguous real-mode areas, the code for the !kvm->arch.using_mmu_notifiers case, the code for pinning pages of guest memory when first accessed and keeping track of which pages have been pinned, and the code for handling H_ENTER hypercalls in virtual mode. Book3S HV KVM is now supported only on POWER7 and POWER8 processors. The KVM_CAP_PPC_RMA capability now always returns 0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:38 +08:00
/* Skip next section on POWER7 */
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
b 8f
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
/* Turn on TM so we can access TFHAR/TFIAR/TEXASR */
mfmsr r8
li r0, 1
rldimi r8, r0, MSR_TM_LG, 63-MSR_TM_LG
mtmsrd r8
/* Load up POWER8-specific registers */
ld r5, VCPU_IAMR(r4)
lwz r6, VCPU_PSPB(r4)
ld r7, VCPU_FSCR(r4)
mtspr SPRN_IAMR, r5
mtspr SPRN_PSPB, r6
mtspr SPRN_FSCR, r7
ld r5, VCPU_DAWR(r4)
ld r6, VCPU_DAWRX(r4)
ld r7, VCPU_CIABR(r4)
ld r8, VCPU_TAR(r4)
mtspr SPRN_DAWR, r5
mtspr SPRN_DAWRX, r6
mtspr SPRN_CIABR, r7
mtspr SPRN_TAR, r8
ld r5, VCPU_IC(r4)
ld r6, VCPU_VTB(r4)
mtspr SPRN_IC, r5
mtspr SPRN_VTB, r6
KVM: PPC: Book3S HV: Add new state for transactional memory Add new state for transactional memory (TM) to kvm_vcpu_arch. Also add asm-offset bits that are going to be required. This also moves the existing TFHAR, TFIAR and TEXASR SPRs into a CONFIG_PPC_TRANSACTIONAL_MEM section. This requires some code changes to ensure we still compile with CONFIG_PPC_TRANSACTIONAL_MEM=N. Much of the added the added #ifdefs are removed in a later patch when the bulk of the TM code is added. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix merge conflict] Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:32 +08:00
ld r8, VCPU_EBBHR(r4)
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
mtspr SPRN_EBBHR, r8
ld r5, VCPU_EBBRR(r4)
ld r6, VCPU_BESCR(r4)
ld r7, VCPU_CSIGR(r4)
ld r8, VCPU_TACR(r4)
mtspr SPRN_EBBRR, r5
mtspr SPRN_BESCR, r6
mtspr SPRN_CSIGR, r7
mtspr SPRN_TACR, r8
ld r5, VCPU_TCSCR(r4)
ld r6, VCPU_ACOP(r4)
lwz r7, VCPU_GUEST_PID(r4)
ld r8, VCPU_WORT(r4)
mtspr SPRN_TCSCR, r5
mtspr SPRN_ACOP, r6
mtspr SPRN_PID, r7
mtspr SPRN_WORT, r8
8:
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/*
* Set the decrementer to the guest decrementer.
*/
ld r8,VCPU_DEC_EXPIRES(r4)
KVM: PPC: Book3S HV: Fix decrementer timeouts with non-zero TB offset Commit c7699822bc21 ("KVM: PPC: Book3S HV: Make physical thread 0 do the MMU switching") reordered the guest entry/exit code so that most of the guest register save/restore code happened in guest MMU context. A side effect of that is that the timebase still contains the guest timebase value at the point where we compute and use vcpu->arch.dec_expires, and therefore that is now a guest timebase value rather than a host timebase value. That in turn means that the timeouts computed in kvmppc_set_timer() are wrong if the timebase offset for the guest is non-zero. The consequence of that is things such as "sleep 1" in a guest after migration may sleep for much longer than they should. This fixes the problem by converting between guest and host timebase values as necessary, by adding or subtracting the timebase offset. This also fixes an incorrect comment. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:07 +08:00
/* r8 is a host timebase value here, convert to guest TB */
ld r5,HSTATE_KVM_VCORE(r13)
ld r6,VCORE_TB_OFFSET(r5)
add r8,r8,r6
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
mftb r7
subf r3,r7,r8
mtspr SPRN_DEC,r3
stw r3,VCPU_DEC(r4)
ld r5, VCPU_SPRG0(r4)
ld r6, VCPU_SPRG1(r4)
ld r7, VCPU_SPRG2(r4)
ld r8, VCPU_SPRG3(r4)
mtspr SPRN_SPRG0, r5
mtspr SPRN_SPRG1, r6
mtspr SPRN_SPRG2, r7
mtspr SPRN_SPRG3, r8
/* Load up DAR and DSISR */
ld r5, VCPU_DAR(r4)
lwz r6, VCPU_DSISR(r4)
mtspr SPRN_DAR, r5
mtspr SPRN_DSISR, r6
/* Restore AMR and UAMOR, set AMOR to all 1s */
ld r5,VCPU_AMR(r4)
ld r6,VCPU_UAMOR(r4)
li r7,-1
mtspr SPRN_AMR,r5
mtspr SPRN_UAMOR,r6
mtspr SPRN_AMOR,r7
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Restore state of CTRL run bit; assume 1 on entry */
lwz r5,VCPU_CTRL(r4)
andi. r5,r5,1
bne 4f
mfspr r6,SPRN_CTRLF
clrrdi r6,r6,1
mtspr SPRN_CTRLT,r6
4:
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
/* Secondary threads wait for primary to have done partition switch */
ld r5, HSTATE_KVM_VCORE(r13)
lbz r6, HSTATE_PTID(r13)
cmpwi r6, 0
beq 21f
lbz r0, VCORE_IN_GUEST(r5)
cmpwi r0, 0
bne 21f
HMT_LOW
20: lbz r0, VCORE_IN_GUEST(r5)
cmpwi r0, 0
beq 20b
HMT_MEDIUM
21:
/* Set LPCR. */
ld r8,VCORE_LPCR(r5)
mtspr SPRN_LPCR,r8
isync
/* Check if HDEC expires soon */
mfspr r3, SPRN_HDEC
cmpwi r3, 512 /* 1 microsecond */
blt hdec_soon
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
ld r6, VCPU_CTR(r4)
lwz r7, VCPU_XER(r4)
mtctr r6
mtxer r7
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
kvmppc_cede_reentry: /* r4 = vcpu, r13 = paca */
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
ld r10, VCPU_PC(r4)
ld r11, VCPU_MSR(r4)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
ld r6, VCPU_SRR0(r4)
ld r7, VCPU_SRR1(r4)
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
mtspr SPRN_SRR0, r6
mtspr SPRN_SRR1, r7
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
deliver_guest_interrupt:
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
/* r11 = vcpu->arch.msr & ~MSR_HV */
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
rldicl r11, r11, 63 - MSR_HV_LG, 1
rotldi r11, r11, 1 + MSR_HV_LG
ori r11, r11, MSR_ME
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* Check if we can deliver an external or decrementer interrupt now */
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
ld r0, VCPU_PENDING_EXC(r4)
rldicl r0, r0, 64 - BOOK3S_IRQPRIO_EXTERNAL_LEVEL, 63
cmpdi cr1, r0, 0
andi. r8, r11, MSR_EE
mfspr r8, SPRN_LPCR
/* Insert EXTERNAL_LEVEL bit into LPCR at the MER bit position */
rldimi r8, r0, LPCR_MER_SH, 63 - LPCR_MER_SH
mtspr SPRN_LPCR, r8
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
isync
beq 5f
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
li r0, BOOK3S_INTERRUPT_EXTERNAL
bne cr1, 12f
mfspr r0, SPRN_DEC
cmpwi r0, 0
li r0, BOOK3S_INTERRUPT_DECREMENTER
bge 5f
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
12: mtspr SPRN_SRR0, r10
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
mr r10,r0
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
mtspr SPRN_SRR1, r11
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
mr r9, r4
bl kvmppc_msr_interrupt
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
5:
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
powerpc: kvm: optimize "sc 1" as fast return In some scene, e.g openstack CI, PR guest can trigger "sc 1" frequently, this patch optimizes the path by directly delivering BOOK3S_INTERRUPT_SYSCALL to HV guest, so powernv can return to HV guest without heavy exit, i.e, no need to swap TLB, HTAB,.. etc Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-19 14:12:48 +08:00
/*
* Required state:
* R4 = vcpu
* R10: value for HSRR0
* R11: value for HSRR1
* R13 = PACA
*/
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
fast_guest_return:
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
li r0,0
stb r0,VCPU_CEDED(r4) /* cancel cede */
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
mtspr SPRN_HSRR0,r10
mtspr SPRN_HSRR1,r11
/* Activate guest mode, so faults get handled by KVM */
KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode When an interrupt or exception happens in the guest that comes to the host, the CPU goes to hypervisor real mode (MMU off) to handle the exception but doesn't change the MMU context. After saving a few registers, we then clear the "in guest" flag. If, for any reason, we get an exception in the real-mode code, that then gets handled by the normal kernel exception handlers, which turn the MMU on. This is disastrous if the MMU is still set to the guest context, since we end up executing instructions from random places in the guest kernel with hypervisor privilege. In order to catch this situation, we define a new value for the "in guest" flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real mode with guest MMU context. If the "in guest" flag is set to this value, we branch off to an emergency handler. For the moment, this just does a branch to self to stop the CPU from doing anything further. While we're here, we define another new flag value to indicate that we are in a HV guest, as distinct from a PR guest. This will be useful when we have a kernel that can support both PR and HV guests concurrently. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-04 19:45:04 +08:00
li r9, KVM_GUEST_MODE_GUEST_HV
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
stb r9, HSTATE_IN_GUEST(r13)
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
/* Accumulate timing */
addi r3, r4, VCPU_TB_GUEST
bl kvmhv_accumulate_time
#endif
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Enter guest */
powerpc/kvm/book3s_hv: Preserve guest CFAR register value The CFAR (Come-From Address Register) is a useful debugging aid that exists on POWER7 processors. Currently HV KVM doesn't save or restore the CFAR register for guest vcpus, making the CFAR of limited use in guests. This adds the necessary code to capture the CFAR value saved in the early exception entry code (it has to be saved before any branch is executed), save it in the vcpu.arch struct, and restore it on entry to the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-02-05 02:10:51 +08:00
BEGIN_FTR_SECTION
ld r5, VCPU_CFAR(r4)
mtspr SPRN_CFAR, r5
END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
KVM: PPC: Book3S HV: Add support for guest Program Priority Register POWER7 and later IBM server processors have a register called the Program Priority Register (PPR), which controls the priority of each hardware CPU SMT thread, and affects how fast it runs compared to other SMT threads. This priority can be controlled by writing to the PPR or by use of a set of instructions of the form or rN,rN,rN which are otherwise no-ops but have been defined to set the priority to particular levels. This adds code to context switch the PPR when entering and exiting guests and to make the PPR value accessible through the SET/GET_ONE_REG interface. When entering the guest, we set the PPR as late as possible, because if we are setting a low thread priority it will make the code run slowly from that point on. Similarly, the first-level interrupt handlers save the PPR value in the PACA very early on, and set the thread priority to the medium level, so that the interrupt handling code runs at a reasonable speed. Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-20 12:52:39 +08:00
BEGIN_FTR_SECTION
ld r0, VCPU_PPR(r4)
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
powerpc/kvm/book3s_hv: Preserve guest CFAR register value The CFAR (Come-From Address Register) is a useful debugging aid that exists on POWER7 processors. Currently HV KVM doesn't save or restore the CFAR register for guest vcpus, making the CFAR of limited use in guests. This adds the necessary code to capture the CFAR value saved in the early exception entry code (it has to be saved before any branch is executed), save it in the vcpu.arch struct, and restore it on entry to the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-02-05 02:10:51 +08:00
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
ld r5, VCPU_LR(r4)
lwz r6, VCPU_CR(r4)
mtlr r5
mtcr r6
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
ld r1, VCPU_GPR(R1)(r4)
ld r2, VCPU_GPR(R2)(r4)
ld r3, VCPU_GPR(R3)(r4)
ld r5, VCPU_GPR(R5)(r4)
ld r6, VCPU_GPR(R6)(r4)
ld r7, VCPU_GPR(R7)(r4)
ld r8, VCPU_GPR(R8)(r4)
ld r9, VCPU_GPR(R9)(r4)
ld r10, VCPU_GPR(R10)(r4)
ld r11, VCPU_GPR(R11)(r4)
ld r12, VCPU_GPR(R12)(r4)
ld r13, VCPU_GPR(R13)(r4)
KVM: PPC: Book3S HV: Add support for guest Program Priority Register POWER7 and later IBM server processors have a register called the Program Priority Register (PPR), which controls the priority of each hardware CPU SMT thread, and affects how fast it runs compared to other SMT threads. This priority can be controlled by writing to the PPR or by use of a set of instructions of the form or rN,rN,rN which are otherwise no-ops but have been defined to set the priority to particular levels. This adds code to context switch the PPR when entering and exiting guests and to make the PPR value accessible through the SET/GET_ONE_REG interface. When entering the guest, we set the PPR as late as possible, because if we are setting a low thread priority it will make the code run slowly from that point on. Similarly, the first-level interrupt handlers save the PPR value in the PACA very early on, and set the thread priority to the medium level, so that the interrupt handling code runs at a reasonable speed. Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-20 12:52:39 +08:00
BEGIN_FTR_SECTION
mtspr SPRN_PPR, r0
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ld r0, VCPU_GPR(R0)(r4)
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
ld r4, VCPU_GPR(R4)(r4)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
hrfid
b .
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
secondary_too_late:
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
li r12, 0
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
cmpdi r4, 0
beq 11f
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
stw r12, VCPU_TRAP(r4)
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
addi r3, r4, VCPU_TB_RMEXIT
bl kvmhv_accumulate_time
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
#endif
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
11: b kvmhv_switch_to_host
hdec_soon:
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
li r12, BOOK3S_INTERRUPT_HV_DECREMENTER
stw r12, VCPU_TRAP(r4)
mr r9, r4
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
addi r3, r4, VCPU_TB_RMEXIT
bl kvmhv_accumulate_time
#endif
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
b guest_exit_cont
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/******************************************************************************
* *
* Exit code *
* *
*****************************************************************************/
/*
* We come here from the first-level interrupt handlers.
*/
kvm: powerpc: book3s: Cleanup interrupt handling code With this patch if HV is included, interrupts come in to the HV version of the kvmppc_interrupt code, which then jumps to the PR handler, renamed to kvmppc_interrupt_pr, if the guest is a PR guest. This helps in enabling both HV and PR, which we do in later patch Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-08 00:47:55 +08:00
.globl kvmppc_interrupt_hv
kvmppc_interrupt_hv:
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/*
* Register contents:
* R12 = interrupt vector
* R13 = PACA
* guest CR, R12 saved in shadow VCPU SCRATCH1/0
* guest R13 saved in SPRN_SCRATCH0
*/
powerpc: book3s: kvm: Don't abuse host r2 in exit path We don't use PACATOC for PR. Avoid updating HOST_R2 with PR KVM mode when both HV and PR are enabled in the kernel. Without this we get the below crash (qemu) Unable to handle kernel paging request for data at address 0xffffffffffff8310 Faulting instruction address: 0xc00000000001d5a4 cpu 0x2: Vector: 300 (Data Access) at [c0000001dc53aef0] pc: c00000000001d5a4: .vtime_delta.isra.1+0x34/0x1d0 lr: c00000000001d760: .vtime_account_system+0x20/0x60 sp: c0000001dc53b170 msr: 8000000000009032 dar: ffffffffffff8310 dsisr: 40000000 current = 0xc0000001d76c62d0 paca = 0xc00000000fef1100 softe: 0 irq_happened: 0x01 pid = 4472, comm = qemu-system-ppc enter ? for help [c0000001dc53b200] c00000000001d760 .vtime_account_system+0x20/0x60 [c0000001dc53b290] c00000000008d050 .kvmppc_handle_exit_pr+0x60/0xa50 [c0000001dc53b340] c00000000008f51c kvm_start_lightweight+0xb4/0xc4 [c0000001dc53b510] c00000000008cdf0 .kvmppc_vcpu_run_pr+0x150/0x2e0 [c0000001dc53b9e0] c00000000008341c .kvmppc_vcpu_run+0x2c/0x40 [c0000001dc53ba50] c000000000080af4 .kvm_arch_vcpu_ioctl_run+0x54/0x1b0 [c0000001dc53bae0] c00000000007b4c8 .kvm_vcpu_ioctl+0x478/0x730 [c0000001dc53bca0] c0000000002140cc .do_vfs_ioctl+0x4ac/0x770 [c0000001dc53bd80] c0000000002143e8 .SyS_ioctl+0x58/0xb0 [c0000001dc53be30] c000000000009e58 syscall_exit+0x0/0x98 Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-11 21:59:47 +08:00
std r9, HSTATE_SCRATCH2(r13)
KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode When an interrupt or exception happens in the guest that comes to the host, the CPU goes to hypervisor real mode (MMU off) to handle the exception but doesn't change the MMU context. After saving a few registers, we then clear the "in guest" flag. If, for any reason, we get an exception in the real-mode code, that then gets handled by the normal kernel exception handlers, which turn the MMU on. This is disastrous if the MMU is still set to the guest context, since we end up executing instructions from random places in the guest kernel with hypervisor privilege. In order to catch this situation, we define a new value for the "in guest" flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real mode with guest MMU context. If the "in guest" flag is set to this value, we branch off to an emergency handler. For the moment, this just does a branch to self to stop the CPU from doing anything further. While we're here, we define another new flag value to indicate that we are in a HV guest, as distinct from a PR guest. This will be useful when we have a kernel that can support both PR and HV guests concurrently. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-04 19:45:04 +08:00
lbz r9, HSTATE_IN_GUEST(r13)
cmpwi r9, KVM_GUEST_MODE_HOST_HV
beq kvmppc_bad_host_intr
kvm: powerpc: book3s: Cleanup interrupt handling code With this patch if HV is included, interrupts come in to the HV version of the kvmppc_interrupt code, which then jumps to the PR handler, renamed to kvmppc_interrupt_pr, if the guest is a PR guest. This helps in enabling both HV and PR, which we do in later patch Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-08 00:47:55 +08:00
#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
cmpwi r9, KVM_GUEST_MODE_GUEST
powerpc: book3s: kvm: Don't abuse host r2 in exit path We don't use PACATOC for PR. Avoid updating HOST_R2 with PR KVM mode when both HV and PR are enabled in the kernel. Without this we get the below crash (qemu) Unable to handle kernel paging request for data at address 0xffffffffffff8310 Faulting instruction address: 0xc00000000001d5a4 cpu 0x2: Vector: 300 (Data Access) at [c0000001dc53aef0] pc: c00000000001d5a4: .vtime_delta.isra.1+0x34/0x1d0 lr: c00000000001d760: .vtime_account_system+0x20/0x60 sp: c0000001dc53b170 msr: 8000000000009032 dar: ffffffffffff8310 dsisr: 40000000 current = 0xc0000001d76c62d0 paca = 0xc00000000fef1100 softe: 0 irq_happened: 0x01 pid = 4472, comm = qemu-system-ppc enter ? for help [c0000001dc53b200] c00000000001d760 .vtime_account_system+0x20/0x60 [c0000001dc53b290] c00000000008d050 .kvmppc_handle_exit_pr+0x60/0xa50 [c0000001dc53b340] c00000000008f51c kvm_start_lightweight+0xb4/0xc4 [c0000001dc53b510] c00000000008cdf0 .kvmppc_vcpu_run_pr+0x150/0x2e0 [c0000001dc53b9e0] c00000000008341c .kvmppc_vcpu_run+0x2c/0x40 [c0000001dc53ba50] c000000000080af4 .kvm_arch_vcpu_ioctl_run+0x54/0x1b0 [c0000001dc53bae0] c00000000007b4c8 .kvm_vcpu_ioctl+0x478/0x730 [c0000001dc53bca0] c0000000002140cc .do_vfs_ioctl+0x4ac/0x770 [c0000001dc53bd80] c0000000002143e8 .SyS_ioctl+0x58/0xb0 [c0000001dc53be30] c000000000009e58 syscall_exit+0x0/0x98 Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-11 21:59:47 +08:00
ld r9, HSTATE_SCRATCH2(r13)
kvm: powerpc: book3s: Cleanup interrupt handling code With this patch if HV is included, interrupts come in to the HV version of the kvmppc_interrupt code, which then jumps to the PR handler, renamed to kvmppc_interrupt_pr, if the guest is a PR guest. This helps in enabling both HV and PR, which we do in later patch Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-08 00:47:55 +08:00
beq kvmppc_interrupt_pr
#endif
KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode When an interrupt or exception happens in the guest that comes to the host, the CPU goes to hypervisor real mode (MMU off) to handle the exception but doesn't change the MMU context. After saving a few registers, we then clear the "in guest" flag. If, for any reason, we get an exception in the real-mode code, that then gets handled by the normal kernel exception handlers, which turn the MMU on. This is disastrous if the MMU is still set to the guest context, since we end up executing instructions from random places in the guest kernel with hypervisor privilege. In order to catch this situation, we define a new value for the "in guest" flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real mode with guest MMU context. If the "in guest" flag is set to this value, we branch off to an emergency handler. For the moment, this just does a branch to self to stop the CPU from doing anything further. While we're here, we define another new flag value to indicate that we are in a HV guest, as distinct from a PR guest. This will be useful when we have a kernel that can support both PR and HV guests concurrently. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-04 19:45:04 +08:00
/* We're now back in the host but in guest MMU context */
li r9, KVM_GUEST_MODE_HOST_HV
stb r9, HSTATE_IN_GUEST(r13)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
ld r9, HSTATE_KVM_VCPU(r13)
/* Save registers */
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
std r0, VCPU_GPR(R0)(r9)
std r1, VCPU_GPR(R1)(r9)
std r2, VCPU_GPR(R2)(r9)
std r3, VCPU_GPR(R3)(r9)
std r4, VCPU_GPR(R4)(r9)
std r5, VCPU_GPR(R5)(r9)
std r6, VCPU_GPR(R6)(r9)
std r7, VCPU_GPR(R7)(r9)
std r8, VCPU_GPR(R8)(r9)
powerpc: book3s: kvm: Don't abuse host r2 in exit path We don't use PACATOC for PR. Avoid updating HOST_R2 with PR KVM mode when both HV and PR are enabled in the kernel. Without this we get the below crash (qemu) Unable to handle kernel paging request for data at address 0xffffffffffff8310 Faulting instruction address: 0xc00000000001d5a4 cpu 0x2: Vector: 300 (Data Access) at [c0000001dc53aef0] pc: c00000000001d5a4: .vtime_delta.isra.1+0x34/0x1d0 lr: c00000000001d760: .vtime_account_system+0x20/0x60 sp: c0000001dc53b170 msr: 8000000000009032 dar: ffffffffffff8310 dsisr: 40000000 current = 0xc0000001d76c62d0 paca = 0xc00000000fef1100 softe: 0 irq_happened: 0x01 pid = 4472, comm = qemu-system-ppc enter ? for help [c0000001dc53b200] c00000000001d760 .vtime_account_system+0x20/0x60 [c0000001dc53b290] c00000000008d050 .kvmppc_handle_exit_pr+0x60/0xa50 [c0000001dc53b340] c00000000008f51c kvm_start_lightweight+0xb4/0xc4 [c0000001dc53b510] c00000000008cdf0 .kvmppc_vcpu_run_pr+0x150/0x2e0 [c0000001dc53b9e0] c00000000008341c .kvmppc_vcpu_run+0x2c/0x40 [c0000001dc53ba50] c000000000080af4 .kvm_arch_vcpu_ioctl_run+0x54/0x1b0 [c0000001dc53bae0] c00000000007b4c8 .kvm_vcpu_ioctl+0x478/0x730 [c0000001dc53bca0] c0000000002140cc .do_vfs_ioctl+0x4ac/0x770 [c0000001dc53bd80] c0000000002143e8 .SyS_ioctl+0x58/0xb0 [c0000001dc53be30] c000000000009e58 syscall_exit+0x0/0x98 Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-11 21:59:47 +08:00
ld r0, HSTATE_SCRATCH2(r13)
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
std r0, VCPU_GPR(R9)(r9)
std r10, VCPU_GPR(R10)(r9)
std r11, VCPU_GPR(R11)(r9)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
ld r3, HSTATE_SCRATCH0(r13)
lwz r4, HSTATE_SCRATCH1(r13)
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
std r3, VCPU_GPR(R12)(r9)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
stw r4, VCPU_CR(r9)
powerpc/kvm/book3s_hv: Preserve guest CFAR register value The CFAR (Come-From Address Register) is a useful debugging aid that exists on POWER7 processors. Currently HV KVM doesn't save or restore the CFAR register for guest vcpus, making the CFAR of limited use in guests. This adds the necessary code to capture the CFAR value saved in the early exception entry code (it has to be saved before any branch is executed), save it in the vcpu.arch struct, and restore it on entry to the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-02-05 02:10:51 +08:00
BEGIN_FTR_SECTION
ld r3, HSTATE_CFAR(r13)
std r3, VCPU_CFAR(r9)
END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
KVM: PPC: Book3S HV: Add support for guest Program Priority Register POWER7 and later IBM server processors have a register called the Program Priority Register (PPR), which controls the priority of each hardware CPU SMT thread, and affects how fast it runs compared to other SMT threads. This priority can be controlled by writing to the PPR or by use of a set of instructions of the form or rN,rN,rN which are otherwise no-ops but have been defined to set the priority to particular levels. This adds code to context switch the PPR when entering and exiting guests and to make the PPR value accessible through the SET/GET_ONE_REG interface. When entering the guest, we set the PPR as late as possible, because if we are setting a low thread priority it will make the code run slowly from that point on. Similarly, the first-level interrupt handlers save the PPR value in the PACA very early on, and set the thread priority to the medium level, so that the interrupt handling code runs at a reasonable speed. Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-20 12:52:39 +08:00
BEGIN_FTR_SECTION
ld r4, HSTATE_PPR(r13)
std r4, VCPU_PPR(r9)
END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Restore R1/R2 so we can handle faults */
ld r1, HSTATE_HOST_R1(r13)
ld r2, PACATOC(r13)
mfspr r10, SPRN_SRR0
mfspr r11, SPRN_SRR1
std r10, VCPU_SRR0(r9)
std r11, VCPU_SRR1(r9)
andi. r0, r12, 2 /* need to read HSRR0/1? */
beq 1f
mfspr r10, SPRN_HSRR0
mfspr r11, SPRN_HSRR1
clrrdi r12, r12, 2
1: std r10, VCPU_PC(r9)
std r11, VCPU_MSR(r9)
GET_SCRATCH0(r3)
mflr r4
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
std r3, VCPU_GPR(R13)(r9)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
std r4, VCPU_LR(r9)
stw r12,VCPU_TRAP(r9)
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
addi r3, r9, VCPU_TB_RMINTR
mr r4, r9
bl kvmhv_accumulate_time
ld r5, VCPU_GPR(R5)(r9)
ld r6, VCPU_GPR(R6)(r9)
ld r7, VCPU_GPR(R7)(r9)
ld r8, VCPU_GPR(R8)(r9)
#endif
KVM: PPC: Book3S HV: Fix endianness of instruction obtained from HEIR register There are two ways in which a guest instruction can be obtained from the guest in the guest exit code in book3s_hv_rmhandlers.S. If the exit was caused by a Hypervisor Emulation interrupt (i.e. an illegal instruction), the offending instruction is in the HEIR register (Hypervisor Emulation Instruction Register). If the exit was caused by a load or store to an emulated MMIO device, we load the instruction from the guest by turning data relocation on and loading the instruction with an lwz instruction. Unfortunately, in the case where the guest has opposite endianness to the host, these two methods give results of different endianness, but both get put into vcpu->arch.last_inst. The HEIR value has been loaded using guest endianness, whereas the lwz will load the instruction using host endianness. The rest of the code that uses vcpu->arch.last_inst assumes it was loaded using host endianness. To fix this, we define a new vcpu field to store the HEIR value. Then, in kvmppc_handle_exit_hv(), we transfer the value from this new field to vcpu->arch.last_inst, doing a byte-swap if the guest and host endianness differ. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:39 +08:00
/* Save HEIR (HV emulation assist reg) in emul_inst
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
if this is an HEI (HV emulation interrupt, e40) */
li r3,KVM_INST_FETCH_FAILED
KVM: PPC: Book3S HV: Fix instruction emulation Commit 4a157d61b48c ("KVM: PPC: Book3S HV: Fix endianness of instruction obtained from HEIR register") had the side effect that we no longer reset vcpu->arch.last_inst to -1 on guest exit in the cases where the instruction is not fetched from the guest. This means that if instruction emulation turns out to be required in those cases, the host will emulate the wrong instruction, since vcpu->arch.last_inst will contain the last instruction that was emulated. This fixes it by making sure that vcpu->arch.last_inst is reset to -1 in those cases. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-20 17:39:40 +08:00
stw r3,VCPU_LAST_INST(r9)
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
cmpwi r12,BOOK3S_INTERRUPT_H_EMUL_ASSIST
bne 11f
mfspr r3,SPRN_HEIR
KVM: PPC: Book3S HV: Fix endianness of instruction obtained from HEIR register There are two ways in which a guest instruction can be obtained from the guest in the guest exit code in book3s_hv_rmhandlers.S. If the exit was caused by a Hypervisor Emulation interrupt (i.e. an illegal instruction), the offending instruction is in the HEIR register (Hypervisor Emulation Instruction Register). If the exit was caused by a load or store to an emulated MMIO device, we load the instruction from the guest by turning data relocation on and loading the instruction with an lwz instruction. Unfortunately, in the case where the guest has opposite endianness to the host, these two methods give results of different endianness, but both get put into vcpu->arch.last_inst. The HEIR value has been loaded using guest endianness, whereas the lwz will load the instruction using host endianness. The rest of the code that uses vcpu->arch.last_inst assumes it was loaded using host endianness. To fix this, we define a new vcpu field to store the HEIR value. Then, in kvmppc_handle_exit_hv(), we transfer the value from this new field to vcpu->arch.last_inst, doing a byte-swap if the guest and host endianness differ. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:39 +08:00
11: stw r3,VCPU_HEIR(r9)
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
/* these are volatile across C function calls */
mfctr r3
mfxer r4
std r3, VCPU_CTR(r9)
stw r4, VCPU_XER(r9)
/* If this is a page table miss then see if it's theirs or ours */
cmpwi r12, BOOK3S_INTERRUPT_H_DATA_STORAGE
beq kvmppc_hdsi
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
cmpwi r12, BOOK3S_INTERRUPT_H_INST_STORAGE
beq kvmppc_hisi
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* See if this is a leftover HDEC interrupt */
cmpwi r12,BOOK3S_INTERRUPT_HV_DECREMENTER
bne 2f
mfspr r3,SPRN_HDEC
cmpwi r3,0
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
mr r4,r9
bge fast_guest_return
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
2:
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
/* See if this is an hcall we can handle in real mode */
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
cmpwi r12,BOOK3S_INTERRUPT_SYSCALL
beq hcall_try_real_mode
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 This uses msgsnd where possible for signalling other threads within the same core on POWER8 systems, rather than IPIs through the XICS interrupt controller. This includes waking secondary threads to run the guest, the interrupts generated by the virtual XICS, and the interrupts to bring the other threads out of the guest when exiting. Aggregated statistics from debugfs across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, show this before the change: rm_entry: 3387.6ns (228 - 86600, 1008969 samples) rm_exit: 4561.5ns (12 - 3477452, 1009402 samples) rm_intr: 1660.0ns (12 - 553050, 3600051 samples) and this after the change: rm_entry: 3060.1ns (212 - 65138, 953873 samples) rm_exit: 4244.1ns (12 - 9693408, 954331 samples) rm_intr: 1342.3ns (12 - 1104718, 3405326 samples) for a test of booting Fedora 20 big-endian to the login prompt. The time taken for a H_PROD hcall (which is handled in the host kernel) went down from about 35 microseconds to about 16 microseconds with this change. The noinline added to kvmppc_run_core turned out to be necessary for good performance, at least with gcc 4.9.2 as packaged with Fedora 21 and a little-endian POWER8 host. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:12 +08:00
/* Hypervisor doorbell - exit only if host IPI flag set */
cmpwi r12, BOOK3S_INTERRUPT_H_DOORBELL
bne 3f
lbz r0, HSTATE_HOST_IPI(r13)
beq 4f
b guest_exit_cont
3:
KVM: PPC: Book3S HV: Speed up wakeups of CPUs on HV KVM Currently, we wake up a CPU by sending a host IPI with smp_send_reschedule() to thread 0 of that core, which will take all threads out of the guest, and cause them to re-evaluate their interrupt status on the way back in. This adds a mechanism to differentiate real host IPIs from IPIs sent by KVM for guest threads to poke each other, in order to target the guest threads precisely when possible and avoid that global switch of the core to host state. We then use this new facility in the in-kernel XICS code. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:30:50 +08:00
/* External interrupt ? */
cmpwi r12, BOOK3S_INTERRUPT_EXTERNAL
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
bne+ guest_exit_cont
KVM: PPC: Book3S HV: Speed up wakeups of CPUs on HV KVM Currently, we wake up a CPU by sending a host IPI with smp_send_reschedule() to thread 0 of that core, which will take all threads out of the guest, and cause them to re-evaluate their interrupt status on the way back in. This adds a mechanism to differentiate real host IPIs from IPIs sent by KVM for guest threads to poke each other, in order to target the guest threads precisely when possible and avoid that global switch of the core to host state. We then use this new facility in the in-kernel XICS code. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:30:50 +08:00
/* External interrupt, first check for host_ipi. If this is
* set, we know the host wants us out so let's do it now
*/
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
bl kvmppc_read_intr
cmpdi r3, 0
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
bgt guest_exit_cont
KVM: PPC: Book3S HV: Speed up wakeups of CPUs on HV KVM Currently, we wake up a CPU by sending a host IPI with smp_send_reschedule() to thread 0 of that core, which will take all threads out of the guest, and cause them to re-evaluate their interrupt status on the way back in. This adds a mechanism to differentiate real host IPIs from IPIs sent by KVM for guest threads to poke each other, in order to target the guest threads precisely when possible and avoid that global switch of the core to host state. We then use this new facility in the in-kernel XICS code. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:30:50 +08:00
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
/* Check if any CPU is heading out to the host, if so head out too */
KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 This uses msgsnd where possible for signalling other threads within the same core on POWER8 systems, rather than IPIs through the XICS interrupt controller. This includes waking secondary threads to run the guest, the interrupts generated by the virtual XICS, and the interrupts to bring the other threads out of the guest when exiting. Aggregated statistics from debugfs across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, show this before the change: rm_entry: 3387.6ns (228 - 86600, 1008969 samples) rm_exit: 4561.5ns (12 - 3477452, 1009402 samples) rm_intr: 1660.0ns (12 - 553050, 3600051 samples) and this after the change: rm_entry: 3060.1ns (212 - 65138, 953873 samples) rm_exit: 4244.1ns (12 - 9693408, 954331 samples) rm_intr: 1342.3ns (12 - 1104718, 3405326 samples) for a test of booting Fedora 20 big-endian to the login prompt. The time taken for a H_PROD hcall (which is handled in the host kernel) went down from about 35 microseconds to about 16 microseconds with this change. The noinline added to kvmppc_run_core turned out to be necessary for good performance, at least with gcc 4.9.2 as packaged with Fedora 21 and a little-endian POWER8 host. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:12 +08:00
4: ld r5, HSTATE_KVM_VCORE(r13)
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
lwz r0, VCORE_ENTRY_EXIT(r5)
cmpwi r0, 0x100
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
mr r4, r9
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
blt deliver_guest_interrupt
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
guest_exit_cont: /* r9 = vcpu, r12 = trap, r13 = paca */
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Save more register state */
mfdar r6
mfdsisr r7
std r6, VCPU_DAR(r9)
stw r7, VCPU_DSISR(r9)
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
/* don't overwrite fault_dar/fault_dsisr if HDSI */
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
cmpwi r12,BOOK3S_INTERRUPT_H_DATA_STORAGE
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
beq mc_cont
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
std r6, VCPU_FAULT_DAR(r9)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
stw r7, VCPU_FAULT_DSISR(r9)
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
/* See if it is a machine check */
cmpwi r12, BOOK3S_INTERRUPT_MACHINE_CHECK
beq machine_check_realmode
mc_cont:
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
addi r3, r9, VCPU_TB_RMEXIT
mr r4, r9
bl kvmhv_accumulate_time
#endif
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
/* Increment exit count, poke other threads to exit */
bl kvmhv_commence_exit
KVM: PPC: Book3S HV: Translate kvmhv_commence_exit to C This replaces the assembler code for kvmhv_commence_exit() with C code in book3s_hv_builtin.c. It also moves the IPI sending code that was in book3s_hv_rm_xics.c into a new kvmhv_rm_send_ipi() function so it can be used by kvmhv_commence_exit() as well as icp_rm_set_vcpu_irq(). Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:11 +08:00
nop
ld r9, HSTATE_KVM_VCPU(r13)
lwz r12, VCPU_TRAP(r9)
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Save guest CTRL register, set runlatch to 1 */
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
mfspr r6,SPRN_CTRLF
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
stw r6,VCPU_CTRL(r9)
andi. r0,r6,1
bne 4f
ori r6,r6,1
mtspr SPRN_CTRLT,r6
4:
/* Read the guest SLB and save it away */
lwz r0,VCPU_SLB_NR(r9) /* number of entries in SLB */
mtctr r0
li r6,0
addi r7,r9,VCPU_SLB
li r5,0
1: slbmfee r8,r6
andis. r0,r8,SLB_ESID_V@h
beq 2f
add r8,r8,r6 /* put index in */
slbmfev r3,r6
std r8,VCPU_SLB_E(r7)
std r3,VCPU_SLB_V(r7)
addi r7,r7,VCPU_SLB_SIZE
addi r5,r5,1
2: addi r6,r6,1
bdnz 1b
stw r5,VCPU_SLB_MAX(r9)
/*
* Save the guest PURR/SPURR
*/
mfspr r5,SPRN_PURR
mfspr r6,SPRN_SPURR
ld r7,VCPU_PURR(r9)
ld r8,VCPU_SPURR(r9)
std r5,VCPU_PURR(r9)
std r6,VCPU_SPURR(r9)
subf r5,r7,r5
subf r6,r8,r6
/*
* Restore host PURR/SPURR and add guest times
* so that the time in the guest gets accounted.
*/
ld r3,HSTATE_PURR(r13)
ld r4,HSTATE_SPURR(r13)
add r3,r3,r5
add r4,r4,r6
mtspr SPRN_PURR,r3
mtspr SPRN_SPURR,r4
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Save DEC */
mfspr r5,SPRN_DEC
mftb r6
extsw r5,r5
add r5,r5,r6
KVM: PPC: Book3S HV: Fix decrementer timeouts with non-zero TB offset Commit c7699822bc21 ("KVM: PPC: Book3S HV: Make physical thread 0 do the MMU switching") reordered the guest entry/exit code so that most of the guest register save/restore code happened in guest MMU context. A side effect of that is that the timebase still contains the guest timebase value at the point where we compute and use vcpu->arch.dec_expires, and therefore that is now a guest timebase value rather than a host timebase value. That in turn means that the timeouts computed in kvmppc_set_timer() are wrong if the timebase offset for the guest is non-zero. The consequence of that is things such as "sleep 1" in a guest after migration may sleep for much longer than they should. This fixes the problem by converting between guest and host timebase values as necessary, by adding or subtracting the timebase offset. This also fixes an incorrect comment. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:07 +08:00
/* r5 is a guest timebase value here, convert to host TB */
ld r3,HSTATE_KVM_VCORE(r13)
ld r4,VCORE_TB_OFFSET(r3)
subf r5,r4,r5
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
std r5,VCPU_DEC_EXPIRES(r9)
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
BEGIN_FTR_SECTION
b 8f
END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
/* Save POWER8-specific registers */
mfspr r5, SPRN_IAMR
mfspr r6, SPRN_PSPB
mfspr r7, SPRN_FSCR
std r5, VCPU_IAMR(r9)
stw r6, VCPU_PSPB(r9)
std r7, VCPU_FSCR(r9)
mfspr r5, SPRN_IC
mfspr r6, SPRN_VTB
mfspr r7, SPRN_TAR
std r5, VCPU_IC(r9)
std r6, VCPU_VTB(r9)
std r7, VCPU_TAR(r9)
KVM: PPC: Book3S HV: Add new state for transactional memory Add new state for transactional memory (TM) to kvm_vcpu_arch. Also add asm-offset bits that are going to be required. This also moves the existing TFHAR, TFIAR and TEXASR SPRs into a CONFIG_PPC_TRANSACTIONAL_MEM section. This requires some code changes to ensure we still compile with CONFIG_PPC_TRANSACTIONAL_MEM=N. Much of the added the added #ifdefs are removed in a later patch when the bulk of the TM code is added. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix merge conflict] Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:32 +08:00
mfspr r8, SPRN_EBBHR
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
std r8, VCPU_EBBHR(r9)
mfspr r5, SPRN_EBBRR
mfspr r6, SPRN_BESCR
mfspr r7, SPRN_CSIGR
mfspr r8, SPRN_TACR
std r5, VCPU_EBBRR(r9)
std r6, VCPU_BESCR(r9)
std r7, VCPU_CSIGR(r9)
std r8, VCPU_TACR(r9)
mfspr r5, SPRN_TCSCR
mfspr r6, SPRN_ACOP
mfspr r7, SPRN_PID
mfspr r8, SPRN_WORT
std r5, VCPU_TCSCR(r9)
std r6, VCPU_ACOP(r9)
stw r7, VCPU_GUEST_PID(r9)
std r8, VCPU_WORT(r9)
8:
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Save and reset AMR and UAMOR before turning on the MMU */
mfspr r5,SPRN_AMR
mfspr r6,SPRN_UAMOR
std r5,VCPU_AMR(r9)
std r6,VCPU_UAMOR(r9)
li r6,0
mtspr SPRN_AMR,r6
/* Switch DSCR back to host value */
mfspr r8, SPRN_DSCR
ld r7, HSTATE_DSCR(r13)
std r8, VCPU_DSCR(r9)
mtspr SPRN_DSCR, r7
/* Save non-volatile GPRs */
std r14, VCPU_GPR(R14)(r9)
std r15, VCPU_GPR(R15)(r9)
std r16, VCPU_GPR(R16)(r9)
std r17, VCPU_GPR(R17)(r9)
std r18, VCPU_GPR(R18)(r9)
std r19, VCPU_GPR(R19)(r9)
std r20, VCPU_GPR(R20)(r9)
std r21, VCPU_GPR(R21)(r9)
std r22, VCPU_GPR(R22)(r9)
std r23, VCPU_GPR(R23)(r9)
std r24, VCPU_GPR(R24)(r9)
std r25, VCPU_GPR(R25)(r9)
std r26, VCPU_GPR(R26)(r9)
std r27, VCPU_GPR(R27)(r9)
std r28, VCPU_GPR(R28)(r9)
std r29, VCPU_GPR(R29)(r9)
std r30, VCPU_GPR(R30)(r9)
std r31, VCPU_GPR(R31)(r9)
/* Save SPRGs */
mfspr r3, SPRN_SPRG0
mfspr r4, SPRN_SPRG1
mfspr r5, SPRN_SPRG2
mfspr r6, SPRN_SPRG3
std r3, VCPU_SPRG0(r9)
std r4, VCPU_SPRG1(r9)
std r5, VCPU_SPRG2(r9)
std r6, VCPU_SPRG3(r9)
/* save FP state */
mr r3, r9
bl kvmppc_save_fp
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit Testing by Michael Neuling revealed that commit e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support") is missing the code that saves away the checkpointed state of the guest when switching to the host. This adds that code, which was in earlier versions of the patch but went missing somehow. Reported-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-04-14 06:56:26 +08:00
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BEGIN_FTR_SECTION
b 2f
END_FTR_SECTION_IFCLR(CPU_FTR_TM)
/* Turn on TM. */
mfmsr r8
li r0, 1
rldimi r8, r0, MSR_TM_LG, 63-MSR_TM_LG
mtmsrd r8
ld r5, VCPU_MSR(r9)
rldicl. r5, r5, 64 - MSR_TS_S_LG, 62
beq 1f /* TM not active in guest. */
li r3, TM_CAUSE_KVM_RESCHED
/* Clear the MSR RI since r1, r13 are all going to be foobar. */
li r5, 0
mtmsrd r5, 1
/* All GPRs are volatile at this point. */
TRECLAIM(R3)
/* Temporarily store r13 and r9 so we have some regs to play with */
SET_SCRATCH0(r13)
GET_PACA(r13)
std r9, PACATMSCRATCH(r13)
ld r9, HSTATE_KVM_VCPU(r13)
/* Get a few more GPRs free. */
std r29, VCPU_GPRS_TM(29)(r9)
std r30, VCPU_GPRS_TM(30)(r9)
std r31, VCPU_GPRS_TM(31)(r9)
/* Save away PPR and DSCR soon so don't run with user values. */
mfspr r31, SPRN_PPR
HMT_MEDIUM
mfspr r30, SPRN_DSCR
ld r29, HSTATE_DSCR(r13)
mtspr SPRN_DSCR, r29
/* Save all but r9, r13 & r29-r31 */
reg = 0
.rept 29
.if (reg != 9) && (reg != 13)
std reg, VCPU_GPRS_TM(reg)(r9)
.endif
reg = reg + 1
.endr
/* ... now save r13 */
GET_SCRATCH0(r4)
std r4, VCPU_GPRS_TM(13)(r9)
/* ... and save r9 */
ld r4, PACATMSCRATCH(r13)
std r4, VCPU_GPRS_TM(9)(r9)
/* Reload stack pointer and TOC. */
ld r1, HSTATE_HOST_R1(r13)
ld r2, PACATOC(r13)
/* Set MSR RI now we have r1 and r13 back. */
li r5, MSR_RI
mtmsrd r5, 1
/* Save away checkpinted SPRs. */
std r31, VCPU_PPR_TM(r9)
std r30, VCPU_DSCR_TM(r9)
mflr r5
mfcr r6
mfctr r7
mfspr r8, SPRN_AMR
mfspr r10, SPRN_TAR
std r5, VCPU_LR_TM(r9)
stw r6, VCPU_CR_TM(r9)
std r7, VCPU_CTR_TM(r9)
std r8, VCPU_AMR_TM(r9)
std r10, VCPU_TAR_TM(r9)
/* Restore r12 as trap number. */
lwz r12, VCPU_TRAP(r9)
/* Save FP/VSX. */
addi r3, r9, VCPU_FPRS_TM
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl store_fp_state
KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit Testing by Michael Neuling revealed that commit e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support") is missing the code that saves away the checkpointed state of the guest when switching to the host. This adds that code, which was in earlier versions of the patch but went missing somehow. Reported-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-04-14 06:56:26 +08:00
addi r3, r9, VCPU_VRS_TM
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl store_vr_state
KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit Testing by Michael Neuling revealed that commit e4e38121507a ("KVM: PPC: Book3S HV: Add transactional memory support") is missing the code that saves away the checkpointed state of the guest when switching to the host. This adds that code, which was in earlier versions of the patch but went missing somehow. Reported-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-04-14 06:56:26 +08:00
mfspr r6, SPRN_VRSAVE
stw r6, VCPU_VRSAVE_TM(r9)
1:
/*
* We need to save these SPRs after the treclaim so that the software
* error code is recorded correctly in the TEXASR. Also the user may
* change these outside of a transaction, so they must always be
* context switched.
*/
mfspr r5, SPRN_TFHAR
mfspr r6, SPRN_TFIAR
mfspr r7, SPRN_TEXASR
std r5, VCPU_TFHAR(r9)
std r6, VCPU_TFIAR(r9)
std r7, VCPU_TEXASR(r9)
2:
#endif
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
/* Increment yield count if they have a VPA */
ld r8, VCPU_VPA(r9) /* do they have a VPA? */
cmpdi r8, 0
beq 25f
KVM: PPC: Book3S HV: Access host lppaca and shadow slb in BE Some data structures are always stored in big endian. Among those are the LPPACA fields as well as the shadow slb. These structures might be shared with a hypervisor. So whenever we access those fields, make sure we do so in big endian byte order. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-11 16:36:17 +08:00
li r4, LPPACA_YIELDCOUNT
LWZX_BE r3, r8, r4
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
addi r3, r3, 1
KVM: PPC: Book3S HV: Access host lppaca and shadow slb in BE Some data structures are always stored in big endian. Among those are the LPPACA fields as well as the shadow slb. These structures might be shared with a hypervisor. So whenever we access those fields, make sure we do so in big endian byte order. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-11 16:36:17 +08:00
STWX_BE r3, r8, r4
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
li r3, 1
stb r3, VCPU_VPA_DIRTY(r9)
25:
/* Save PMU registers if requested */
/* r8 and cr0.eq are live here */
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs This adds workarounds for two hardware bugs in the POWER8 performance monitor unit (PMU), both related to interrupt generation. The effect of these bugs is that PMU interrupts can get lost, leading to tools such as perf reporting fewer counts and samples than they should. The first bug relates to the PMAO (perf. mon. alert occurred) bit in MMCR0; setting it should cause an interrupt, but doesn't. The other bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0. Setting PMAE when a counter is negative and counter negative conditions are enabled to cause alerts should cause an alert, but doesn't. The workaround for the first bug is to create conditions where a counter will overflow, whenever we are about to restore a MMCR0 value that has PMAO set (and PMAO_SYNC clear). The workaround for the second bug is to freeze all counters using MMCR2 before reading MMCR0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-26 17:48:40 +08:00
BEGIN_FTR_SECTION
/*
* POWER8 seems to have a hardware bug where setting
* MMCR0[PMAE] along with MMCR0[PMC1CE] and/or MMCR0[PMCjCE]
* when some counters are already negative doesn't seem
* to cause a performance monitor alert (and hence interrupt).
* The effect of this is that when saving the PMU state,
* if there is no PMU alert pending when we read MMCR0
* before freezing the counters, but one becomes pending
* before we read the counters, we lose it.
* To work around this, we need a way to freeze the counters
* before reading MMCR0. Normally, freezing the counters
* is done by writing MMCR0 (to set MMCR0[FC]) which
* unavoidably writes MMCR0[PMA0] as well. On POWER8,
* we can also freeze the counters using MMCR2, by writing
* 1s to all the counter freeze condition bits (there are
* 9 bits each for 6 counters).
*/
li r3, -1 /* set all freeze bits */
clrrdi r3, r3, 10
mfspr r10, SPRN_MMCR2
mtspr SPRN_MMCR2, r3
isync
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
li r3, 1
sldi r3, r3, 31 /* MMCR0_FC (freeze counters) bit */
mfspr r4, SPRN_MMCR0 /* save MMCR0 */
mtspr SPRN_MMCR0, r3 /* freeze all counters, disable ints */
mfspr r6, SPRN_MMCRA
KVM: PPC: Book3S HV: Remove code for PPC970 processors This removes the code that was added to enable HV KVM to work on PPC970 processors. The PPC970 is an old CPU that doesn't support virtualizing guest memory. Removing PPC970 support also lets us remove the code for allocating and managing contiguous real-mode areas, the code for the !kvm->arch.using_mmu_notifiers case, the code for pinning pages of guest memory when first accessed and keeping track of which pages have been pinned, and the code for handling H_ENTER hypercalls in virtual mode. Book3S HV KVM is now supported only on POWER7 and POWER8 processors. The KVM_CAP_PPC_RMA capability now always returns 0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:38 +08:00
/* Clear MMCRA in order to disable SDAR updates */
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
li r7, 0
mtspr SPRN_MMCRA, r7
isync
beq 21f /* if no VPA, save PMU stuff anyway */
lbz r7, LPPACA_PMCINUSE(r8)
cmpwi r7, 0 /* did they ask for PMU stuff to be saved? */
bne 21f
std r3, VCPU_MMCR(r9) /* if not, set saved MMCR0 to FC */
b 22f
21: mfspr r5, SPRN_MMCR1
mfspr r7, SPRN_SIAR
mfspr r8, SPRN_SDAR
std r4, VCPU_MMCR(r9)
std r5, VCPU_MMCR + 8(r9)
std r6, VCPU_MMCR + 16(r9)
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs This adds workarounds for two hardware bugs in the POWER8 performance monitor unit (PMU), both related to interrupt generation. The effect of these bugs is that PMU interrupts can get lost, leading to tools such as perf reporting fewer counts and samples than they should. The first bug relates to the PMAO (perf. mon. alert occurred) bit in MMCR0; setting it should cause an interrupt, but doesn't. The other bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0. Setting PMAE when a counter is negative and counter negative conditions are enabled to cause alerts should cause an alert, but doesn't. The workaround for the first bug is to create conditions where a counter will overflow, whenever we are about to restore a MMCR0 value that has PMAO set (and PMAO_SYNC clear). The workaround for the second bug is to freeze all counters using MMCR2 before reading MMCR0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-26 17:48:40 +08:00
BEGIN_FTR_SECTION
std r10, VCPU_MMCR + 24(r9)
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
std r7, VCPU_SIAR(r9)
std r8, VCPU_SDAR(r9)
mfspr r3, SPRN_PMC1
mfspr r4, SPRN_PMC2
mfspr r5, SPRN_PMC3
mfspr r6, SPRN_PMC4
mfspr r7, SPRN_PMC5
mfspr r8, SPRN_PMC6
stw r3, VCPU_PMC(r9)
stw r4, VCPU_PMC + 4(r9)
stw r5, VCPU_PMC + 8(r9)
stw r6, VCPU_PMC + 12(r9)
stw r7, VCPU_PMC + 16(r9)
stw r8, VCPU_PMC + 20(r9)
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
BEGIN_FTR_SECTION
mfspr r5, SPRN_SIER
mfspr r6, SPRN_SPMC1
mfspr r7, SPRN_SPMC2
mfspr r8, SPRN_MMCRS
std r5, VCPU_SIER(r9)
stw r6, VCPU_PMC + 24(r9)
stw r7, VCPU_PMC + 28(r9)
std r8, VCPU_MMCR + 32(r9)
lis r4, 0x8000
mtspr SPRN_MMCRS, r4
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
22:
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/* Clear out SLB */
li r5,0
slbmte r5,r5
slbia
ptesync
KVM: PPC: book3s_hv: Add support for PPC970-family processors This adds support for running KVM guests in supervisor mode on those PPC970 processors that have a usable hypervisor mode. Unfortunately, Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to 1), but the YDL PowerStation does have a usable hypervisor mode. There are several differences between the PPC970 and POWER7 in how guests are managed. These differences are accommodated using the CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature bits. Notably, on PPC970: * The LPCR, LPID or RMOR registers don't exist, and the functions of those registers are provided by bits in HID4 and one bit in HID0. * External interrupts can be directed to the hypervisor, but unlike POWER7 they are masked by MSR[EE] in non-hypervisor modes and use SRR0/1 not HSRR0/1. * There is no virtual RMA (VRMA) mode; the guest must use an RMO (real mode offset) area. * The TLB entries are not tagged with the LPID, so it is necessary to flush the whole TLB on partition switch. Furthermore, when switching partitions we have to ensure that no other CPU is executing the tlbie or tlbsync instructions in either the old or the new partition, otherwise undefined behaviour can occur. * The PMU has 8 counters (PMC registers) rather than 6. * The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist. * The SLB has 64 entries rather than 32. * There is no mediated external interrupt facility, so if we switch to a guest that has a virtual external interrupt pending but the guest has MSR[EE] = 0, we have to arrange to have an interrupt pending for it so that we can get control back once it re-enables interrupts. We do that by sending ourselves an IPI with smp_send_reschedule after hard-disabling interrupts. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:40:08 +08:00
/*
KVM: PPC: Book3S HV: Remove code for PPC970 processors This removes the code that was added to enable HV KVM to work on PPC970 processors. The PPC970 is an old CPU that doesn't support virtualizing guest memory. Removing PPC970 support also lets us remove the code for allocating and managing contiguous real-mode areas, the code for the !kvm->arch.using_mmu_notifiers case, the code for pinning pages of guest memory when first accessed and keeping track of which pages have been pinned, and the code for handling H_ENTER hypercalls in virtual mode. Book3S HV KVM is now supported only on POWER7 and POWER8 processors. The KVM_CAP_PPC_RMA capability now always returns 0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:38 +08:00
* POWER7/POWER8 guest -> host partition switch code.
KVM: PPC: book3s_hv: Add support for PPC970-family processors This adds support for running KVM guests in supervisor mode on those PPC970 processors that have a usable hypervisor mode. Unfortunately, Apple G5 machines have supervisor mode disabled (MSR[HV] is forced to 1), but the YDL PowerStation does have a usable hypervisor mode. There are several differences between the PPC970 and POWER7 in how guests are managed. These differences are accommodated using the CPU_FTR_ARCH_201 (PPC970) and CPU_FTR_ARCH_206 (POWER7) CPU feature bits. Notably, on PPC970: * The LPCR, LPID or RMOR registers don't exist, and the functions of those registers are provided by bits in HID4 and one bit in HID0. * External interrupts can be directed to the hypervisor, but unlike POWER7 they are masked by MSR[EE] in non-hypervisor modes and use SRR0/1 not HSRR0/1. * There is no virtual RMA (VRMA) mode; the guest must use an RMO (real mode offset) area. * The TLB entries are not tagged with the LPID, so it is necessary to flush the whole TLB on partition switch. Furthermore, when switching partitions we have to ensure that no other CPU is executing the tlbie or tlbsync instructions in either the old or the new partition, otherwise undefined behaviour can occur. * The PMU has 8 counters (PMC registers) rather than 6. * The DSCR, PURR, SPURR, AMR, AMOR, UAMOR registers don't exist. * The SLB has 64 entries rather than 32. * There is no mediated external interrupt facility, so if we switch to a guest that has a virtual external interrupt pending but the guest has MSR[EE] = 0, we have to arrange to have an interrupt pending for it so that we can get control back once it re-enables interrupts. We do that by sending ourselves an IPI with smp_send_reschedule after hard-disabling interrupts. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:40:08 +08:00
* We don't have to lock against tlbies but we do
* have to coordinate the hardware threads.
*/
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
kvmhv_switch_to_host:
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
/* Secondary threads wait for primary to do partition switch */
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
ld r5,HSTATE_KVM_VCORE(r13)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
ld r4,VCORE_KVM(r5) /* pointer to struct kvm */
lbz r3,HSTATE_PTID(r13)
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
cmpwi r3,0
beq 15f
HMT_LOW
13: lbz r3,VCORE_IN_GUEST(r5)
cmpwi r3,0
bne 13b
HMT_MEDIUM
b 16f
/* Primary thread waits for all the secondaries to exit guest */
15: lwz r3,VCORE_ENTRY_EXIT(r5)
srwi r0,r3,8
clrldi r3,r3,56
cmpw r3,r0
bne 15b
isync
/* Primary thread switches back to host partition */
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
ld r6,KVM_HOST_SDR1(r4)
lwz r7,KVM_HOST_LPID(r4)
li r8,LPID_RSVD /* switch to reserved LPID */
mtspr SPRN_LPID,r8
ptesync
mtspr SPRN_SDR1,r6 /* switch to partition page table */
mtspr SPRN_LPID,r7
isync
KVM: PPC: Book3S HV: Implement timebase offset for guests This allows guests to have a different timebase origin from the host. This is needed for migration, where a guest can migrate from one host to another and the two hosts might have a different timebase origin. However, the timebase seen by the guest must not go backwards, and should go forwards only by a small amount corresponding to the time taken for the migration. Therefore this provides a new per-vcpu value accessed via the one_reg interface using the new KVM_REG_PPC_TB_OFFSET identifier. This value defaults to 0 and is not modified by KVM. On entering the guest, this value is added onto the timebase, and on exiting the guest, it is subtracted from the timebase. This is only supported for recent POWER hardware which has the TBU40 (timebase upper 40 bits) register. Writing to the TBU40 register only alters the upper 40 bits of the timebase, leaving the lower 24 bits unchanged. This provides a way to modify the timebase for guest migration without disturbing the synchronization of the timebase registers across CPU cores. The kernel rounds up the value given to a multiple of 2^24. Timebase values stored in KVM structures (struct kvm_vcpu, struct kvmppc_vcore, etc.) are stored as host timebase values. The timebase values in the dispatch trace log need to be guest timebase values, however, since that is read directly by the guest. This moves the setting of vcpu->arch.dec_expires on guest exit to a point after we have restored the host timebase so that vcpu->arch.dec_expires is a host timebase value. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:17:46 +08:00
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs This adds fields to the struct kvm_vcpu_arch to store the new guest-accessible SPRs on POWER8, adds code to the get/set_one_reg functions to allow userspace to access this state, and adds code to the guest entry and exit to context-switch these SPRs between host and guest. Note that DPDES (Directed Privileged Doorbell Exception State) is shared between threads on a core; hence we store it in struct kvmppc_vcore and have the master thread save and restore it. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:21 +08:00
BEGIN_FTR_SECTION
/* DPDES is shared between threads */
mfspr r7, SPRN_DPDES
std r7, VCORE_DPDES(r5)
/* clear DPDES so we don't get guest doorbells in the host */
li r8, 0
mtspr SPRN_DPDES, r8
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Implement timebase offset for guests This allows guests to have a different timebase origin from the host. This is needed for migration, where a guest can migrate from one host to another and the two hosts might have a different timebase origin. However, the timebase seen by the guest must not go backwards, and should go forwards only by a small amount corresponding to the time taken for the migration. Therefore this provides a new per-vcpu value accessed via the one_reg interface using the new KVM_REG_PPC_TB_OFFSET identifier. This value defaults to 0 and is not modified by KVM. On entering the guest, this value is added onto the timebase, and on exiting the guest, it is subtracted from the timebase. This is only supported for recent POWER hardware which has the TBU40 (timebase upper 40 bits) register. Writing to the TBU40 register only alters the upper 40 bits of the timebase, leaving the lower 24 bits unchanged. This provides a way to modify the timebase for guest migration without disturbing the synchronization of the timebase registers across CPU cores. The kernel rounds up the value given to a multiple of 2^24. Timebase values stored in KVM structures (struct kvm_vcpu, struct kvmppc_vcore, etc.) are stored as host timebase values. The timebase values in the dispatch trace log need to be guest timebase values, however, since that is read directly by the guest. This moves the setting of vcpu->arch.dec_expires on guest exit to a point after we have restored the host timebase so that vcpu->arch.dec_expires is a host timebase value. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:17:46 +08:00
/* Subtract timebase offset from timebase */
ld r8,VCORE_TB_OFFSET(r5)
cmpdi r8,0
beq 17f
KVM: PPC: Book3S HV: Fix decrementer timeouts with non-zero TB offset Commit c7699822bc21 ("KVM: PPC: Book3S HV: Make physical thread 0 do the MMU switching") reordered the guest entry/exit code so that most of the guest register save/restore code happened in guest MMU context. A side effect of that is that the timebase still contains the guest timebase value at the point where we compute and use vcpu->arch.dec_expires, and therefore that is now a guest timebase value rather than a host timebase value. That in turn means that the timeouts computed in kvmppc_set_timer() are wrong if the timebase offset for the guest is non-zero. The consequence of that is things such as "sleep 1" in a guest after migration may sleep for much longer than they should. This fixes the problem by converting between guest and host timebase values as necessary, by adding or subtracting the timebase offset. This also fixes an incorrect comment. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:07 +08:00
mftb r6 /* current guest timebase */
KVM: PPC: Book3S HV: Implement timebase offset for guests This allows guests to have a different timebase origin from the host. This is needed for migration, where a guest can migrate from one host to another and the two hosts might have a different timebase origin. However, the timebase seen by the guest must not go backwards, and should go forwards only by a small amount corresponding to the time taken for the migration. Therefore this provides a new per-vcpu value accessed via the one_reg interface using the new KVM_REG_PPC_TB_OFFSET identifier. This value defaults to 0 and is not modified by KVM. On entering the guest, this value is added onto the timebase, and on exiting the guest, it is subtracted from the timebase. This is only supported for recent POWER hardware which has the TBU40 (timebase upper 40 bits) register. Writing to the TBU40 register only alters the upper 40 bits of the timebase, leaving the lower 24 bits unchanged. This provides a way to modify the timebase for guest migration without disturbing the synchronization of the timebase registers across CPU cores. The kernel rounds up the value given to a multiple of 2^24. Timebase values stored in KVM structures (struct kvm_vcpu, struct kvmppc_vcore, etc.) are stored as host timebase values. The timebase values in the dispatch trace log need to be guest timebase values, however, since that is read directly by the guest. This moves the setting of vcpu->arch.dec_expires on guest exit to a point after we have restored the host timebase so that vcpu->arch.dec_expires is a host timebase value. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:17:46 +08:00
subf r8,r8,r6
mtspr SPRN_TBU40,r8 /* update upper 40 bits */
mftb r7 /* check if lower 24 bits overflowed */
clrldi r6,r6,40
clrldi r7,r7,40
cmpld r7,r6
bge 17f
addis r8,r8,0x100 /* if so, increment upper 40 bits */
mtspr SPRN_TBU40,r8
KVM: PPC: Book3S HV: Support POWER6 compatibility mode on POWER7 This enables us to use the Processor Compatibility Register (PCR) on POWER7 to put the processor into architecture 2.05 compatibility mode when running a guest. In this mode the new instructions and registers that were introduced on POWER7 are disabled in user mode. This includes all the VSX facilities plus several other instructions such as ldbrx, stdbrx, popcntw, popcntd, etc. To select this mode, we have a new register accessible through the set/get_one_reg interface, called KVM_REG_PPC_ARCH_COMPAT. Setting this to zero gives the full set of capabilities of the processor. Setting it to one of the "logical" PVR values defined in PAPR puts the vcpu into the compatibility mode for the corresponding architecture level. The supported values are: 0x0f000002 Architecture 2.05 (POWER6) 0x0f000003 Architecture 2.06 (POWER7) 0x0f100003 Architecture 2.06+ (POWER7+) Since the PCR is per-core, the architecture compatibility level and the corresponding PCR value are stored in the struct kvmppc_vcore, and are therefore shared between all vcpus in a virtual core. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: squash in fix to add missing break statements and documentation] Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-21 12:35:02 +08:00
/* Reset PCR */
17: ld r0, VCORE_PCR(r5)
cmpdi r0, 0
beq 18f
li r0, 0
mtspr SPRN_PCR, r0
18:
KVM: PPC: Book3S HV: Implement timebase offset for guests This allows guests to have a different timebase origin from the host. This is needed for migration, where a guest can migrate from one host to another and the two hosts might have a different timebase origin. However, the timebase seen by the guest must not go backwards, and should go forwards only by a small amount corresponding to the time taken for the migration. Therefore this provides a new per-vcpu value accessed via the one_reg interface using the new KVM_REG_PPC_TB_OFFSET identifier. This value defaults to 0 and is not modified by KVM. On entering the guest, this value is added onto the timebase, and on exiting the guest, it is subtracted from the timebase. This is only supported for recent POWER hardware which has the TBU40 (timebase upper 40 bits) register. Writing to the TBU40 register only alters the upper 40 bits of the timebase, leaving the lower 24 bits unchanged. This provides a way to modify the timebase for guest migration without disturbing the synchronization of the timebase registers across CPU cores. The kernel rounds up the value given to a multiple of 2^24. Timebase values stored in KVM structures (struct kvm_vcpu, struct kvmppc_vcore, etc.) are stored as host timebase values. The timebase values in the dispatch trace log need to be guest timebase values, however, since that is read directly by the guest. This moves the setting of vcpu->arch.dec_expires on guest exit to a point after we have restored the host timebase so that vcpu->arch.dec_expires is a host timebase value. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:17:46 +08:00
/* Signal secondary CPUs to continue */
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
stb r0,VCORE_IN_GUEST(r5)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
lis r8,0x7fff /* MAX_INT@h */
mtspr SPRN_HDEC,r8
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
16: ld r8,KVM_HOST_LPCR(r4)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
mtspr SPRN_LPCR,r8
isync
/* load host SLB entries */
KVM: PPC: Book3S HV: Remove code for PPC970 processors This removes the code that was added to enable HV KVM to work on PPC970 processors. The PPC970 is an old CPU that doesn't support virtualizing guest memory. Removing PPC970 support also lets us remove the code for allocating and managing contiguous real-mode areas, the code for the !kvm->arch.using_mmu_notifiers case, the code for pinning pages of guest memory when first accessed and keeping track of which pages have been pinned, and the code for handling H_ENTER hypercalls in virtual mode. Book3S HV KVM is now supported only on POWER7 and POWER8 processors. The KVM_CAP_PPC_RMA capability now always returns 0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:38 +08:00
ld r8,PACA_SLBSHADOWPTR(r13)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
.rept SLB_NUM_BOLTED
KVM: PPC: Book3S HV: Access host lppaca and shadow slb in BE Some data structures are always stored in big endian. Among those are the LPPACA fields as well as the shadow slb. These structures might be shared with a hypervisor. So whenever we access those fields, make sure we do so in big endian byte order. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-11 16:36:17 +08:00
li r3, SLBSHADOW_SAVEAREA
LDX_BE r5, r8, r3
addi r3, r3, 8
LDX_BE r6, r8, r3
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
andis. r7,r5,SLB_ESID_V@h
beq 1f
slbmte r6,r5
1: addi r8,r8,16
.endr
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
/* Finish timing, if we have a vcpu */
ld r4, HSTATE_KVM_VCPU(r13)
cmpdi r4, 0
li r3, 0
beq 2f
bl kvmhv_accumulate_time
2:
#endif
KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode When an interrupt or exception happens in the guest that comes to the host, the CPU goes to hypervisor real mode (MMU off) to handle the exception but doesn't change the MMU context. After saving a few registers, we then clear the "in guest" flag. If, for any reason, we get an exception in the real-mode code, that then gets handled by the normal kernel exception handlers, which turn the MMU on. This is disastrous if the MMU is still set to the guest context, since we end up executing instructions from random places in the guest kernel with hypervisor privilege. In order to catch this situation, we define a new value for the "in guest" flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real mode with guest MMU context. If the "in guest" flag is set to this value, we branch off to an emergency handler. For the moment, this just does a branch to self to stop the CPU from doing anything further. While we're here, we define another new flag value to indicate that we are in a HV guest, as distinct from a PR guest. This will be useful when we have a kernel that can support both PR and HV guests concurrently. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-04 19:45:04 +08:00
/* Unset guest mode */
li r0, KVM_GUEST_MODE_NONE
stb r0, HSTATE_IN_GUEST(r13)
KVM: PPC: Book3S HV: Restructure kvmppc_hv_entry to be a subroutine We have two paths into and out of the low-level guest entry and exit code: from a vcpu task via kvmppc_hv_entry_trampoline, and from the system reset vector for an offline secondary thread on POWER7 via kvm_start_guest. Currently both just branch to kvmppc_hv_entry to enter the guest, and on guest exit, we test the vcpu physical thread ID to detect which way we came in and thus whether we should return to the vcpu task or go back to nap mode. In order to make the code flow clearer, and to keep the code relating to each flow together, this turns kvmppc_hv_entry into a subroutine that follows the normal conventions for call and return. This means that kvmppc_hv_entry_trampoline() and kvmppc_hv_entry() now establish normal stack frames, and we use the normal stack slots for saving return addresses rather than local_paca->kvm_hstate.vmhandler. Apart from that this is mostly moving code around unchanged. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:23:44 +08:00
ld r0, 112+PPC_LR_STKOFF(r1)
addi r1, r1, 112
mtlr r0
blr
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
/*
* Check whether an HDSI is an HPTE not found fault or something else.
* If it is an HPTE not found fault that is due to the guest accessing
* a page that they have mapped but which we have paged out, then
* we continue on with the guest exit path. In all other cases,
* reflect the HDSI to the guest as a DSI.
*/
kvmppc_hdsi:
mfspr r4, SPRN_HDAR
mfspr r6, SPRN_HDSISR
KVM: PPC: Allow for read-only pages backing a Book3S HV guest With this, if a guest does an H_ENTER with a read/write HPTE on a page which is currently read-only, we make the actual HPTE inserted be a read-only version of the HPTE. We now intercept protection faults as well as HPTE not found faults, and for a protection fault we work out whether it should be reflected to the guest (e.g. because the guest HPTE didn't allow write access to usermode) or handled by switching to kernel context and calling kvmppc_book3s_hv_page_fault, which will then request write access to the page and update the actual HPTE. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:51 +08:00
/* HPTE not found fault or protection fault? */
andis. r0, r6, (DSISR_NOHPTE | DSISR_PROTFAULT)@h
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
beq 1f /* if not, send it to the guest */
andi. r0, r11, MSR_DR /* data relocation enabled? */
beq 3f
clrrdi r0, r4, 28
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
PPC_SLBFEE_DOT(R5, R0) /* if so, look up SLB */
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
bne 1f /* if no SLB entry found */
4: std r4, VCPU_FAULT_DAR(r9)
stw r6, VCPU_FAULT_DSISR(r9)
/* Search the hash table. */
mr r3, r9 /* vcpu pointer */
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
li r7, 1 /* data fault */
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl kvmppc_hpte_hv_fault
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
ld r9, HSTATE_KVM_VCPU(r13)
ld r10, VCPU_PC(r9)
ld r11, VCPU_MSR(r9)
li r12, BOOK3S_INTERRUPT_H_DATA_STORAGE
cmpdi r3, 0 /* retry the instruction */
beq 6f
cmpdi r3, -1 /* handle in kernel mode */
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
beq guest_exit_cont
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
cmpdi r3, -2 /* MMIO emulation; need instr word */
beq 2f
/* Synthesize a DSI for the guest */
ld r4, VCPU_FAULT_DAR(r9)
mr r6, r3
1: mtspr SPRN_DAR, r4
mtspr SPRN_DSISR, r6
mtspr SPRN_SRR0, r10
mtspr SPRN_SRR1, r11
li r10, BOOK3S_INTERRUPT_DATA_STORAGE
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
bl kvmppc_msr_interrupt
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
fast_interrupt_c_return:
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
6: ld r7, VCPU_CTR(r9)
lwz r8, VCPU_XER(r9)
mtctr r7
mtxer r8
mr r4, r9
b fast_guest_return
3: ld r5, VCPU_KVM(r9) /* not relocated, use VRMA */
ld r5, KVM_VRMA_SLB_V(r5)
b 4b
/* If this is for emulated MMIO, load the instruction word */
2: li r8, KVM_INST_FETCH_FAILED /* In case lwz faults */
/* Set guest mode to 'jump over instruction' so if lwz faults
* we'll just continue at the next IP. */
li r0, KVM_GUEST_MODE_SKIP
stb r0, HSTATE_IN_GUEST(r13)
/* Do the access with MSR:DR enabled */
mfmsr r3
ori r4, r3, MSR_DR /* Enable paging for data */
mtmsrd r4
lwz r8, 0(r10)
mtmsrd r3
/* Store the result */
stw r8, VCPU_LAST_INST(r9)
/* Unset guest mode. */
KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode When an interrupt or exception happens in the guest that comes to the host, the CPU goes to hypervisor real mode (MMU off) to handle the exception but doesn't change the MMU context. After saving a few registers, we then clear the "in guest" flag. If, for any reason, we get an exception in the real-mode code, that then gets handled by the normal kernel exception handlers, which turn the MMU on. This is disastrous if the MMU is still set to the guest context, since we end up executing instructions from random places in the guest kernel with hypervisor privilege. In order to catch this situation, we define a new value for the "in guest" flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real mode with guest MMU context. If the "in guest" flag is set to this value, we branch off to an emergency handler. For the moment, this just does a branch to self to stop the CPU from doing anything further. While we're here, we define another new flag value to indicate that we are in a HV guest, as distinct from a PR guest. This will be useful when we have a kernel that can support both PR and HV guests concurrently. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-04 19:45:04 +08:00
li r0, KVM_GUEST_MODE_HOST_HV
KVM: PPC: Implement MMIO emulation support for Book3S HV guests This provides the low-level support for MMIO emulation in Book3S HV guests. When the guest tries to map a page which is not covered by any memslot, that page is taken to be an MMIO emulation page. Instead of inserting a valid HPTE, we insert an HPTE that has the valid bit clear but another hypervisor software-use bit set, which we call HPTE_V_ABSENT, to indicate that this is an absent page. An absent page is treated much like a valid page as far as guest hcalls (H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that an absent HPTE doesn't need to be invalidated with tlbie since it was never valid as far as the hardware is concerned. When the guest accesses a page for which there is an absent HPTE, it will take a hypervisor data storage interrupt (HDSI) since we now set the VPM1 bit in the LPCR. Our HDSI handler for HPTE-not-present faults looks up the hash table and if it finds an absent HPTE mapping the requested virtual address, will switch to kernel mode and handle the fault in kvmppc_book3s_hv_page_fault(), which at present just calls kvmppc_hv_emulate_mmio() to set up the MMIO emulation. This is based on an earlier patch by Benjamin Herrenschmidt, but since heavily reworked. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:36:37 +08:00
stb r0, HSTATE_IN_GUEST(r13)
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
b guest_exit_cont
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
/*
* Similarly for an HISI, reflect it to the guest as an ISI unless
* it is an HPTE not found fault for a page that we have paged out.
*/
kvmppc_hisi:
andis. r0, r11, SRR1_ISI_NOPT@h
beq 1f
andi. r0, r11, MSR_IR /* instruction relocation enabled? */
beq 3f
clrrdi r0, r10, 28
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
PPC_SLBFEE_DOT(R5, R0) /* if so, look up SLB */
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
bne 1f /* if no SLB entry found */
4:
/* Search the hash table. */
mr r3, r9 /* vcpu pointer */
mr r4, r10
mr r6, r11
li r7, 0 /* instruction fault */
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl kvmppc_hpte_hv_fault
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
ld r9, HSTATE_KVM_VCPU(r13)
ld r10, VCPU_PC(r9)
ld r11, VCPU_MSR(r9)
li r12, BOOK3S_INTERRUPT_H_INST_STORAGE
cmpdi r3, 0 /* retry the instruction */
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
beq fast_interrupt_c_return
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
cmpdi r3, -1 /* handle in kernel mode */
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
beq guest_exit_cont
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
/* Synthesize an ISI for the guest */
mr r11, r3
1: mtspr SPRN_SRR0, r10
mtspr SPRN_SRR1, r11
li r10, BOOK3S_INTERRUPT_INST_STORAGE
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
bl kvmppc_msr_interrupt
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
b fast_interrupt_c_return
KVM: PPC: Implement MMU notifiers for Book3S HV guests This adds the infrastructure to enable us to page out pages underneath a Book3S HV guest, on processors that support virtualized partition memory, that is, POWER7. Instead of pinning all the guest's pages, we now look in the host userspace Linux page tables to find the mapping for a given guest page. Then, if the userspace Linux PTE gets invalidated, kvm_unmap_hva() gets called for that address, and we replace all the guest HPTEs that refer to that page with absent HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit set, which will cause an HDSI when the guest tries to access them. Finally, the page fault handler is extended to reinstantiate the guest HPTE when the guest tries to access a page which has been paged out. Since we can't intercept the guest DSI and ISI interrupts on PPC970, we still have to pin all the guest pages on PPC970. We have a new flag, kvm->arch.using_mmu_notifiers, that indicates whether we can page guest pages out. If it is not set, the MMU notifier callbacks do nothing and everything operates as before. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-12 20:38:05 +08:00
3: ld r6, VCPU_KVM(r9) /* not relocated, use VRMA */
ld r5, KVM_VRMA_SLB_V(r6)
b 4b
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
/*
* Try to handle an hcall in real mode.
* Returns to the guest if we handle it, or continues on up to
* the kernel if we can't (i.e. if we don't have a handler for
* it, or if the handler returns H_TOO_HARD).
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
*
* r5 - r8 contain hcall args,
* r9 = vcpu, r10 = pc, r11 = msr, r12 = trap, r13 = paca
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
*/
hcall_try_real_mode:
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
ld r3,VCPU_GPR(R3)(r9)
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
andi. r0,r11,MSR_PR
powerpc: kvm: optimize "sc 1" as fast return In some scene, e.g openstack CI, PR guest can trigger "sc 1" frequently, this patch optimizes the path by directly delivering BOOK3S_INTERRUPT_SYSCALL to HV guest, so powernv can return to HV guest without heavy exit, i.e, no need to swap TLB, HTAB,.. etc Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-19 14:12:48 +08:00
/* sc 1 from userspace - reflect to guest syscall */
bne sc_1_fast_return
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
clrrdi r3,r3,2
cmpldi r3,hcall_real_table_end - hcall_real_table
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
bge guest_exit_cont
KVM: PPC: Book3S: Controls for in-kernel sPAPR hypercall handling This provides a way for userspace controls which sPAPR hcalls get handled in the kernel. Each hcall can be individually enabled or disabled for in-kernel handling, except for H_RTAS. The exception for H_RTAS is because userspace can already control whether individual RTAS functions are handled in-kernel or not via the KVM_PPC_RTAS_DEFINE_TOKEN ioctl, and because the numeric value for H_RTAS is out of the normal sequence of hcall numbers. Hcalls are enabled or disabled using the KVM_ENABLE_CAP ioctl for the KVM_CAP_PPC_ENABLE_HCALL capability on the file descriptor for the VM. The args field of the struct kvm_enable_cap specifies the hcall number in args[0] and the enable/disable flag in args[1]; 0 means disable in-kernel handling (so that the hcall will always cause an exit to userspace) and 1 means enable. Enabling or disabling in-kernel handling of an hcall is effective across the whole VM. The ability for KVM_ENABLE_CAP to be used on a VM file descriptor on PowerPC is new, added by this commit. The KVM_CAP_ENABLE_CAP_VM capability advertises that this ability exists. When a VM is created, an initial set of hcalls are enabled for in-kernel handling. The set that is enabled is the set that have an in-kernel implementation at this point. Any new hcall implementations from this point onwards should not be added to the default set without a good reason. No distinction is made between real-mode and virtual-mode hcall implementations; the one setting controls them both. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-02 09:02:59 +08:00
/* See if this hcall is enabled for in-kernel handling */
ld r4, VCPU_KVM(r9)
srdi r0, r3, 8 /* r0 = (r3 / 4) >> 6 */
sldi r0, r0, 3 /* index into kvm->arch.enabled_hcalls[] */
add r4, r4, r0
ld r0, KVM_ENABLED_HCALLS(r4)
rlwinm r4, r3, 32-2, 0x3f /* r4 = (r3 / 4) & 0x3f */
srd r0, r0, r4
andi. r0, r0, 1
beq guest_exit_cont
/* Get pointer to handler, if any, and call it */
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
LOAD_REG_ADDR(r4, hcall_real_table)
KVM: PPC: Book3S HV: Allow negative offsets to real-mode hcall handlers The table of offsets to real-mode hcall handlers in book3s_hv_rmhandlers.S can contain negative values, if some of the handlers end up before the table in the vmlinux binary. Thus we need to use a sign-extending load to read the values in the table rather than a zero-extending load. Without this, the host crashes when the guest does one of the hcalls with negative offsets, due to jumping to a bogus address. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-07-08 18:09:53 +08:00
lwax r3,r3,r4
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
cmpwi r3,0
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
beq guest_exit_cont
KVM: PPC: Book3S HV: Fix ABIv2 indirect branch issue To establish addressability quickly, ABIv2 requires the target address of the function being called to be in r12. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-12 16:16:10 +08:00
add r12,r3,r4
mtctr r12
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
mr r3,r9 /* get vcpu pointer */
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
ld r4,VCPU_GPR(R4)(r9)
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
bctrl
cmpdi r3,H_TOO_HARD
beq hcall_real_fallback
ld r4,HSTATE_KVM_VCPU(r13)
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
std r3,VCPU_GPR(R3)(r4)
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
ld r10,VCPU_PC(r4)
ld r11,VCPU_MSR(r4)
b fast_guest_return
powerpc: kvm: optimize "sc 1" as fast return In some scene, e.g openstack CI, PR guest can trigger "sc 1" frequently, this patch optimizes the path by directly delivering BOOK3S_INTERRUPT_SYSCALL to HV guest, so powernv can return to HV guest without heavy exit, i.e, no need to swap TLB, HTAB,.. etc Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-19 14:12:48 +08:00
sc_1_fast_return:
mtspr SPRN_SRR0,r10
mtspr SPRN_SRR1,r11
li r10, BOOK3S_INTERRUPT_SYSCALL
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
bl kvmppc_msr_interrupt
powerpc: kvm: optimize "sc 1" as fast return In some scene, e.g openstack CI, PR guest can trigger "sc 1" frequently, this patch optimizes the path by directly delivering BOOK3S_INTERRUPT_SYSCALL to HV guest, so powernv can return to HV guest without heavy exit, i.e, no need to swap TLB, HTAB,.. etc Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-19 14:12:48 +08:00
mr r4,r9
b fast_guest_return
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
/* We've attempted a real mode hcall, but it's punted it back
* to userspace. We need to restore some clobbered volatiles
* before resuming the pass-it-to-qemu path */
hcall_real_fallback:
li r12,BOOK3S_INTERRUPT_SYSCALL
ld r9, HSTATE_KVM_VCPU(r13)
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
b guest_exit_cont
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
.globl hcall_real_table
hcall_real_table:
.long 0 /* 0 - unused */
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_h_remove) - hcall_real_table
.long DOTSYM(kvmppc_h_enter) - hcall_real_table
.long DOTSYM(kvmppc_h_read) - hcall_real_table
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
.long 0 /* 0x10 - H_CLEAR_MOD */
.long 0 /* 0x14 - H_CLEAR_REF */
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_h_protect) - hcall_real_table
.long DOTSYM(kvmppc_h_get_tce) - hcall_real_table
.long DOTSYM(kvmppc_h_put_tce) - hcall_real_table
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
.long 0 /* 0x24 - H_SET_SPRG0 */
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_h_set_dabr) - hcall_real_table
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
.long 0 /* 0x2c */
.long 0 /* 0x30 */
.long 0 /* 0x34 */
.long 0 /* 0x38 */
.long 0 /* 0x3c */
.long 0 /* 0x40 */
.long 0 /* 0x44 */
.long 0 /* 0x48 */
.long 0 /* 0x4c */
.long 0 /* 0x50 */
.long 0 /* 0x54 */
.long 0 /* 0x58 */
.long 0 /* 0x5c */
.long 0 /* 0x60 */
KVM: PPC: Book3S HV: Add support for real mode ICP in XICS emulation This adds an implementation of the XICS hypercalls in real mode for HV KVM, which allows us to avoid exiting the guest MMU context on all threads for a variety of operations such as fetching a pending interrupt, EOI of messages, IPIs, etc. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:15 +08:00
#ifdef CONFIG_KVM_XICS
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_rm_h_eoi) - hcall_real_table
.long DOTSYM(kvmppc_rm_h_cppr) - hcall_real_table
.long DOTSYM(kvmppc_rm_h_ipi) - hcall_real_table
KVM: PPC: Book3S HV: Add support for real mode ICP in XICS emulation This adds an implementation of the XICS hypercalls in real mode for HV KVM, which allows us to avoid exiting the guest MMU context on all threads for a variety of operations such as fetching a pending interrupt, EOI of messages, IPIs, etc. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:15 +08:00
.long 0 /* 0x70 - H_IPOLL */
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_rm_h_xirr) - hcall_real_table
KVM: PPC: Book3S HV: Add support for real mode ICP in XICS emulation This adds an implementation of the XICS hypercalls in real mode for HV KVM, which allows us to avoid exiting the guest MMU context on all threads for a variety of operations such as fetching a pending interrupt, EOI of messages, IPIs, etc. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:15 +08:00
#else
.long 0 /* 0x64 - H_EOI */
.long 0 /* 0x68 - H_CPPR */
.long 0 /* 0x6c - H_IPI */
.long 0 /* 0x70 - H_IPOLL */
.long 0 /* 0x74 - H_XIRR */
#endif
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
.long 0 /* 0x78 */
.long 0 /* 0x7c */
.long 0 /* 0x80 */
.long 0 /* 0x84 */
.long 0 /* 0x88 */
.long 0 /* 0x8c */
.long 0 /* 0x90 */
.long 0 /* 0x94 */
.long 0 /* 0x98 */
.long 0 /* 0x9c */
.long 0 /* 0xa0 */
.long 0 /* 0xa4 */
.long 0 /* 0xa8 */
.long 0 /* 0xac */
.long 0 /* 0xb0 */
.long 0 /* 0xb4 */
.long 0 /* 0xb8 */
.long 0 /* 0xbc */
.long 0 /* 0xc0 */
.long 0 /* 0xc4 */
.long 0 /* 0xc8 */
.long 0 /* 0xcc */
.long 0 /* 0xd0 */
.long 0 /* 0xd4 */
.long 0 /* 0xd8 */
.long 0 /* 0xdc */
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_h_cede) - hcall_real_table
KVM: PPC: Book3S HV: Improve H_CONFER implementation Currently the H_CONFER hcall is implemented in kernel virtual mode, meaning that whenever a guest thread does an H_CONFER, all the threads in that virtual core have to exit the guest. This is bad for performance because it interrupts the other threads even if they are doing useful work. The H_CONFER hcall is called by a guest VCPU when it is spinning on a spinlock and it detects that the spinlock is held by a guest VCPU that is currently not running on a physical CPU. The idea is to give this VCPU's time slice to the holder VCPU so that it can make progress towards releasing the lock. To avoid having the other threads exit the guest unnecessarily, we add a real-mode implementation of H_CONFER that checks whether the other threads are doing anything. If all the other threads are idle (i.e. in H_CEDE) or trying to confer (i.e. in H_CONFER), it returns H_TOO_HARD which causes a guest exit and allows the H_CONFER to be handled in virtual mode. Otherwise it spins for a short time (up to 10 microseconds) to give other threads the chance to observe that this thread is trying to confer. The spin loop also terminates when any thread exits the guest or when all other threads are idle or trying to confer. If the timeout is reached, the H_CONFER returns H_SUCCESS. In this case the guest VCPU will recheck the spinlock word and most likely call H_CONFER again. This also improves the implementation of the H_CONFER virtual mode handler. If the VCPU is part of a virtual core (vcore) which is runnable, there will be a 'runner' VCPU which has taken responsibility for running the vcore. In this case we yield to the runner VCPU rather than the target VCPU. We also introduce a check on the target VCPU's yield count: if it differs from the yield count passed to H_CONFER, the target VCPU has run since H_CONFER was called and may have already released the lock. This check is required by PAPR. Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-12-03 10:30:40 +08:00
.long DOTSYM(kvmppc_rm_h_confer) - hcall_real_table
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
.long 0 /* 0xe8 */
.long 0 /* 0xec */
.long 0 /* 0xf0 */
.long 0 /* 0xf4 */
.long 0 /* 0xf8 */
.long 0 /* 0xfc */
.long 0 /* 0x100 */
.long 0 /* 0x104 */
.long 0 /* 0x108 */
.long 0 /* 0x10c */
.long 0 /* 0x110 */
.long 0 /* 0x114 */
.long 0 /* 0x118 */
.long 0 /* 0x11c */
.long 0 /* 0x120 */
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_h_bulk_remove) - hcall_real_table
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7 The DABRX (DABR extension) register on POWER7 processors provides finer control over which accesses cause a data breakpoint interrupt. It contains 3 bits which indicate whether to enable accesses in user, kernel and hypervisor modes respectively to cause data breakpoint interrupts, plus one bit that enables both real mode and virtual mode accesses to cause interrupts. Currently, KVM sets DABRX to allow both kernel and user accesses to cause interrupts while in the guest. This adds support for the guest to specify other values for DABRX. PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR and DABRX with one call. This adds a real-mode implementation of H_SET_XDABR, which shares most of its code with the existing H_SET_DABR implementation. To support this, we add a per-vcpu field to store the DABRX value plus code to get and set it via the ONE_REG interface. For Linux guests to use this new hcall, userspace needs to add "hcall-xdabr" to the set of strings in the /chosen/hypertas-functions property in the device tree. If userspace does this and then migrates the guest to a host where the kernel doesn't include this patch, then userspace will need to implement H_SET_XDABR by writing the specified DABR value to the DABR using the ONE_REG interface. In that case, the old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should still work correctly, at least for Linux guests, since Linux guests cope with getting data breakpoint interrupts in modes that weren't requested by just ignoring the interrupt, and Linux guests never set DABRX_BTI. The other thing this does is to make H_SET_DABR and H_SET_XDABR work on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but guests running in POWER7 compatibility mode will still use H_SET_[X]DABR. For them, this adds the logic to convert DABR/X values into DAWR/X values on POWER8. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:29 +08:00
.long 0 /* 0x128 */
.long 0 /* 0x12c */
.long 0 /* 0x130 */
powerpc: Create DOTSYM to wrap dot symbol usage There are a few places we have to use dot symbols with the current ABI - the syscall table and the kvm hcall table. Wrap both of these with a new macro called DOTSYM so it will be easy to transition away from dot symbols in a future ABI. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:07:01 +08:00
.long DOTSYM(kvmppc_h_set_xdabr) - hcall_real_table
KVM: PPC: Book3S HV: Add fast real-mode H_RANDOM implementation. Some PowerNV systems include a hardware random-number generator. This HWRNG is present on POWER7+ and POWER8 chips and is capable of generating one 64-bit random number every microsecond. The random numbers are produced by sampling a set of 64 unstable high-frequency oscillators and are almost completely entropic. PAPR defines an H_RANDOM hypercall which guests can use to obtain one 64-bit random sample from the HWRNG. This adds a real-mode implementation of the H_RANDOM hypercall. This hypercall was implemented in real mode because the latency of reading the HWRNG is generally small compared to the latency of a guest exit and entry for all the threads in the same virtual core. Userspace can detect the presence of the HWRNG and the H_RANDOM implementation by querying the KVM_CAP_PPC_HWRNG capability. The H_RANDOM hypercall implementation will only be invoked when the guest does an H_RANDOM hypercall if userspace first enables the in-kernel H_RANDOM implementation using the KVM_CAP_PPC_ENABLE_HCALL capability. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-20 17:39:41 +08:00
.long 0 /* 0x138 */
.long 0 /* 0x13c */
.long 0 /* 0x140 */
.long 0 /* 0x144 */
.long 0 /* 0x148 */
.long 0 /* 0x14c */
.long 0 /* 0x150 */
.long 0 /* 0x154 */
.long 0 /* 0x158 */
.long 0 /* 0x15c */
.long 0 /* 0x160 */
.long 0 /* 0x164 */
.long 0 /* 0x168 */
.long 0 /* 0x16c */
.long 0 /* 0x170 */
.long 0 /* 0x174 */
.long 0 /* 0x178 */
.long 0 /* 0x17c */
.long 0 /* 0x180 */
.long 0 /* 0x184 */
.long 0 /* 0x188 */
.long 0 /* 0x18c */
.long 0 /* 0x190 */
.long 0 /* 0x194 */
.long 0 /* 0x198 */
.long 0 /* 0x19c */
.long 0 /* 0x1a0 */
.long 0 /* 0x1a4 */
.long 0 /* 0x1a8 */
.long 0 /* 0x1ac */
.long 0 /* 0x1b0 */
.long 0 /* 0x1b4 */
.long 0 /* 0x1b8 */
.long 0 /* 0x1bc */
.long 0 /* 0x1c0 */
.long 0 /* 0x1c4 */
.long 0 /* 0x1c8 */
.long 0 /* 0x1cc */
.long 0 /* 0x1d0 */
.long 0 /* 0x1d4 */
.long 0 /* 0x1d8 */
.long 0 /* 0x1dc */
.long 0 /* 0x1e0 */
.long 0 /* 0x1e4 */
.long 0 /* 0x1e8 */
.long 0 /* 0x1ec */
.long 0 /* 0x1f0 */
.long 0 /* 0x1f4 */
.long 0 /* 0x1f8 */
.long 0 /* 0x1fc */
.long 0 /* 0x200 */
.long 0 /* 0x204 */
.long 0 /* 0x208 */
.long 0 /* 0x20c */
.long 0 /* 0x210 */
.long 0 /* 0x214 */
.long 0 /* 0x218 */
.long 0 /* 0x21c */
.long 0 /* 0x220 */
.long 0 /* 0x224 */
.long 0 /* 0x228 */
.long 0 /* 0x22c */
.long 0 /* 0x230 */
.long 0 /* 0x234 */
.long 0 /* 0x238 */
.long 0 /* 0x23c */
.long 0 /* 0x240 */
.long 0 /* 0x244 */
.long 0 /* 0x248 */
.long 0 /* 0x24c */
.long 0 /* 0x250 */
.long 0 /* 0x254 */
.long 0 /* 0x258 */
.long 0 /* 0x25c */
.long 0 /* 0x260 */
.long 0 /* 0x264 */
.long 0 /* 0x268 */
.long 0 /* 0x26c */
.long 0 /* 0x270 */
.long 0 /* 0x274 */
.long 0 /* 0x278 */
.long 0 /* 0x27c */
.long 0 /* 0x280 */
.long 0 /* 0x284 */
.long 0 /* 0x288 */
.long 0 /* 0x28c */
.long 0 /* 0x290 */
.long 0 /* 0x294 */
.long 0 /* 0x298 */
.long 0 /* 0x29c */
.long 0 /* 0x2a0 */
.long 0 /* 0x2a4 */
.long 0 /* 0x2a8 */
.long 0 /* 0x2ac */
.long 0 /* 0x2b0 */
.long 0 /* 0x2b4 */
.long 0 /* 0x2b8 */
.long 0 /* 0x2bc */
.long 0 /* 0x2c0 */
.long 0 /* 0x2c4 */
.long 0 /* 0x2c8 */
.long 0 /* 0x2cc */
.long 0 /* 0x2d0 */
.long 0 /* 0x2d4 */
.long 0 /* 0x2d8 */
.long 0 /* 0x2dc */
.long 0 /* 0x2e0 */
.long 0 /* 0x2e4 */
.long 0 /* 0x2e8 */
.long 0 /* 0x2ec */
.long 0 /* 0x2f0 */
.long 0 /* 0x2f4 */
.long 0 /* 0x2f8 */
.long 0 /* 0x2fc */
.long DOTSYM(kvmppc_h_random) - hcall_real_table
KVM: PPC: Book3S: Allow only implemented hcalls to be enabled or disabled This adds code to check that when the KVM_CAP_PPC_ENABLE_HCALL capability is used to enable or disable in-kernel handling of an hcall, that the hcall is actually implemented by the kernel. If not an EINVAL error is returned. This also checks the default-enabled list of hcalls and prints a warning if any hcall there is not actually implemented. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-02 09:03:00 +08:00
.globl hcall_real_table_end
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
hcall_real_table_end:
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7 The DABRX (DABR extension) register on POWER7 processors provides finer control over which accesses cause a data breakpoint interrupt. It contains 3 bits which indicate whether to enable accesses in user, kernel and hypervisor modes respectively to cause data breakpoint interrupts, plus one bit that enables both real mode and virtual mode accesses to cause interrupts. Currently, KVM sets DABRX to allow both kernel and user accesses to cause interrupts while in the guest. This adds support for the guest to specify other values for DABRX. PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR and DABRX with one call. This adds a real-mode implementation of H_SET_XDABR, which shares most of its code with the existing H_SET_DABR implementation. To support this, we add a per-vcpu field to store the DABRX value plus code to get and set it via the ONE_REG interface. For Linux guests to use this new hcall, userspace needs to add "hcall-xdabr" to the set of strings in the /chosen/hypertas-functions property in the device tree. If userspace does this and then migrates the guest to a host where the kernel doesn't include this patch, then userspace will need to implement H_SET_XDABR by writing the specified DABR value to the DABR using the ONE_REG interface. In that case, the old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should still work correctly, at least for Linux guests, since Linux guests cope with getting data breakpoint interrupts in modes that weren't requested by just ignoring the interrupt, and Linux guests never set DABRX_BTI. The other thing this does is to make H_SET_DABR and H_SET_XDABR work on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but guests running in POWER7 compatibility mode will still use H_SET_[X]DABR. For them, this adds the logic to convert DABR/X values into DAWR/X values on POWER8. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:29 +08:00
_GLOBAL(kvmppc_h_set_xdabr)
andi. r0, r5, DABRX_USER | DABRX_KERNEL
beq 6f
li r0, DABRX_USER | DABRX_KERNEL | DABRX_BTI
andc. r0, r5, r0
beq 3f
6: li r3, H_PARAMETER
blr
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
_GLOBAL(kvmppc_h_set_dabr)
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7 The DABRX (DABR extension) register on POWER7 processors provides finer control over which accesses cause a data breakpoint interrupt. It contains 3 bits which indicate whether to enable accesses in user, kernel and hypervisor modes respectively to cause data breakpoint interrupts, plus one bit that enables both real mode and virtual mode accesses to cause interrupts. Currently, KVM sets DABRX to allow both kernel and user accesses to cause interrupts while in the guest. This adds support for the guest to specify other values for DABRX. PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR and DABRX with one call. This adds a real-mode implementation of H_SET_XDABR, which shares most of its code with the existing H_SET_DABR implementation. To support this, we add a per-vcpu field to store the DABRX value plus code to get and set it via the ONE_REG interface. For Linux guests to use this new hcall, userspace needs to add "hcall-xdabr" to the set of strings in the /chosen/hypertas-functions property in the device tree. If userspace does this and then migrates the guest to a host where the kernel doesn't include this patch, then userspace will need to implement H_SET_XDABR by writing the specified DABR value to the DABR using the ONE_REG interface. In that case, the old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should still work correctly, at least for Linux guests, since Linux guests cope with getting data breakpoint interrupts in modes that weren't requested by just ignoring the interrupt, and Linux guests never set DABRX_BTI. The other thing this does is to make H_SET_DABR and H_SET_XDABR work on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but guests running in POWER7 compatibility mode will still use H_SET_[X]DABR. For them, this adds the logic to convert DABR/X values into DAWR/X values on POWER8. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:29 +08:00
li r5, DABRX_USER | DABRX_KERNEL
3:
KVM: PPC: Book3S HV: Don't set DABR on POWER8 POWER8 doesn't have the DABR and DABRX registers; instead it has new DAWR/DAWRX registers, which will be handled in a later patch. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:19 +08:00
BEGIN_FTR_SECTION
b 2f
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
std r4,VCPU_DABR(r3)
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7 The DABRX (DABR extension) register on POWER7 processors provides finer control over which accesses cause a data breakpoint interrupt. It contains 3 bits which indicate whether to enable accesses in user, kernel and hypervisor modes respectively to cause data breakpoint interrupts, plus one bit that enables both real mode and virtual mode accesses to cause interrupts. Currently, KVM sets DABRX to allow both kernel and user accesses to cause interrupts while in the guest. This adds support for the guest to specify other values for DABRX. PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR and DABRX with one call. This adds a real-mode implementation of H_SET_XDABR, which shares most of its code with the existing H_SET_DABR implementation. To support this, we add a per-vcpu field to store the DABRX value plus code to get and set it via the ONE_REG interface. For Linux guests to use this new hcall, userspace needs to add "hcall-xdabr" to the set of strings in the /chosen/hypertas-functions property in the device tree. If userspace does this and then migrates the guest to a host where the kernel doesn't include this patch, then userspace will need to implement H_SET_XDABR by writing the specified DABR value to the DABR using the ONE_REG interface. In that case, the old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should still work correctly, at least for Linux guests, since Linux guests cope with getting data breakpoint interrupts in modes that weren't requested by just ignoring the interrupt, and Linux guests never set DABRX_BTI. The other thing this does is to make H_SET_DABR and H_SET_XDABR work on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but guests running in POWER7 compatibility mode will still use H_SET_[X]DABR. For them, this adds the logic to convert DABR/X values into DAWR/X values on POWER8. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:29 +08:00
stw r5, VCPU_DABRX(r3)
mtspr SPRN_DABRX, r5
KVM: PPC: Work around POWER7 DABR corruption problem It turns out that on POWER7, writing to the DABR can cause a corrupted value to be written if the PMU is active and updating SDAR in continuous sampling mode. To work around this, we make sure that the PMU is inactive and SDAR updates are disabled (via MMCRA) when we are context-switching DABR. When the guest sets DABR via the H_SET_DABR hypercall, we use a slightly different workaround, which is to read back the DABR and write it again if it got corrupted. While we are at it, make it consistent that the saving and restoring of the guest's non-volatile GPRs and the FPRs are done with the guest setup of the PMU active. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-02 09:38:23 +08:00
/* Work around P7 bug where DABR can get corrupted on mtspr */
1: mtspr SPRN_DABR,r4
mfspr r5, SPRN_DABR
cmpd r4, r5
bne 1b
isync
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
li r3,0
blr
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7 The DABRX (DABR extension) register on POWER7 processors provides finer control over which accesses cause a data breakpoint interrupt. It contains 3 bits which indicate whether to enable accesses in user, kernel and hypervisor modes respectively to cause data breakpoint interrupts, plus one bit that enables both real mode and virtual mode accesses to cause interrupts. Currently, KVM sets DABRX to allow both kernel and user accesses to cause interrupts while in the guest. This adds support for the guest to specify other values for DABRX. PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR and DABRX with one call. This adds a real-mode implementation of H_SET_XDABR, which shares most of its code with the existing H_SET_DABR implementation. To support this, we add a per-vcpu field to store the DABRX value plus code to get and set it via the ONE_REG interface. For Linux guests to use this new hcall, userspace needs to add "hcall-xdabr" to the set of strings in the /chosen/hypertas-functions property in the device tree. If userspace does this and then migrates the guest to a host where the kernel doesn't include this patch, then userspace will need to implement H_SET_XDABR by writing the specified DABR value to the DABR using the ONE_REG interface. In that case, the old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should still work correctly, at least for Linux guests, since Linux guests cope with getting data breakpoint interrupts in modes that weren't requested by just ignoring the interrupt, and Linux guests never set DABRX_BTI. The other thing this does is to make H_SET_DABR and H_SET_XDABR work on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but guests running in POWER7 compatibility mode will still use H_SET_[X]DABR. For them, this adds the logic to convert DABR/X values into DAWR/X values on POWER8. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:29 +08:00
/* Emulate H_SET_DABR/X on P8 for the sake of compat mode guests */
2: rlwimi r5, r4, 5, DAWRX_DR | DAWRX_DW
rlwimi r5, r4, 1, DAWRX_WT
clrrdi r4, r4, 3
std r4, VCPU_DAWR(r3)
std r5, VCPU_DAWRX(r3)
mtspr SPRN_DAWR, r4
mtspr SPRN_DAWRX, r5
li r3, 0
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
blr
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
_GLOBAL(kvmppc_h_cede) /* r3 = vcpu pointer, r11 = msr, r13 = paca */
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
ori r11,r11,MSR_EE
std r11,VCPU_MSR(r3)
li r0,1
stb r0,VCPU_CEDED(r3)
sync /* order setting ceded vs. testing prodded */
lbz r5,VCPU_PRODDED(r3)
cmpwi r5,0
KVM: PPC: Book3S HV: Fix incorrect branch in H_CEDE code In handling the H_CEDE hypercall, if this vcpu has already been prodded (with the H_PROD hypercall, which Linux guests don't in fact use), we branch to a numeric label '1f'. Unfortunately there is another '1:' label before the one that we want to jump to. This fixes the problem by using a textual label, 'kvm_cede_prodded'. It also changes the label for another longish branch from '2:' to 'kvm_cede_exit' to avoid a possible future problem if code modifications add another numeric '2:' label in between. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-08-06 08:03:28 +08:00
bne kvm_cede_prodded
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
li r12,0 /* set trap to 0 to say hcall is handled */
stw r12,VCPU_TRAP(r3)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
li r0,H_SUCCESS
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
std r0,VCPU_GPR(R3)(r3)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/*
* Set our bit in the bitmask of napping threads unless all the
* other threads are already napping, in which case we send this
* up to the host.
*/
ld r5,HSTATE_KVM_VCORE(r13)
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
lbz r6,HSTATE_PTID(r13)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
lwz r8,VCORE_ENTRY_EXIT(r5)
clrldi r8,r8,56
li r0,1
sld r0,r0,r6
addi r6,r5,VCORE_NAPPING_THREADS
31: lwarx r4,0,r6
or r4,r4,r0
KVM: PPC: Book3S HV: Use bitmap of active threads rather than count Currently, the entry_exit_count field in the kvmppc_vcore struct contains two 8-bit counts, one of the threads that have started entering the guest, and one of the threads that have started exiting the guest. This changes it to an entry_exit_map field which contains two bitmaps of 8 bits each. The advantage of doing this is that it gives us a bitmap of which threads need to be signalled when exiting the guest. That means that we no longer need to use the trick of setting the HDEC to 0 to pull the other threads out of the guest, which led in some cases to a spurious HDEC interrupt on the next guest entry. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:09 +08:00
cmpw r4,r8
beq kvm_cede_exit
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
stwcx. r4,0,r6
bne 31b
KVM: PPC: Book3S HV: Use bitmap of active threads rather than count Currently, the entry_exit_count field in the kvmppc_vcore struct contains two 8-bit counts, one of the threads that have started entering the guest, and one of the threads that have started exiting the guest. This changes it to an entry_exit_map field which contains two bitmaps of 8 bits each. The advantage of doing this is that it gives us a bitmap of which threads need to be signalled when exiting the guest. That means that we no longer need to use the trick of setting the HDEC to 0 to pull the other threads out of the guest, which led in some cases to a spurious HDEC interrupt on the next guest entry. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:09 +08:00
/* order napping_threads update vs testing entry_exit_map */
KVM: PPC: Book3S HV: Refine barriers in guest entry/exit Some users have reported instances of the host hanging with secondary threads of a core waiting for the primary thread to exit the guest, and the primary thread stuck in nap mode. This prompted a review of the memory barriers in the guest entry/exit code, and this is the result. Most of these changes are the suggestions of Dean Burdick <deanburdick@us.ibm.com>. The barriers between updating napping_threads and reading the entry_exit_count on the one hand, and updating entry_exit_count and reading napping_threads on the other, need to be isync not lwsync, since we need to ensure that either the napping_threads update or the entry_exit_count update get seen. It is not sufficient to order the load vs. lwarx, as lwsync does; we need to order the load vs. the stwcx., so we need isync. In addition, we need a full sync before sending IPIs to wake other threads from nap, to ensure that the write to the entry_exit_count is visible before the IPI occurs. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-11-16 14:46:03 +08:00
isync
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers On a threaded processor such as POWER7, we group VCPUs into virtual cores and arrange that the VCPUs in a virtual core run on the same physical core. Currently we don't enforce any correspondence between virtual thread numbers within a virtual core and physical thread numbers. Physical threads are allocated starting at 0 on a first-come first-served basis to runnable virtual threads (VCPUs). POWER8 implements a new "msgsndp" instruction which guest kernels can use to interrupt other threads in the same core or sub-core. Since the instruction takes the destination physical thread ID as a parameter, it becomes necessary to align the physical thread IDs with the virtual thread IDs, that is, to make sure virtual thread N within a virtual core always runs on physical thread N. This means that it's possible that thread 0, which is where we call __kvmppc_vcore_entry, may end up running some other vcpu than the one whose task called kvmppc_run_core(), or it may end up running no vcpu at all, if for example thread 0 of the virtual core is currently executing in userspace. However, we do need thread 0 to be responsible for switching the MMU -- a previous version of this patch that had other threads switching the MMU was found to be responsible for occasional memory corruption and machine check interrupts in the guest on POWER7 machines. To accommodate this, we no longer pass the vcpu pointer to __kvmppc_vcore_entry, but instead let the assembly code load it from the PACA. Since the assembly code will need to know the kvm pointer and the thread ID for threads which don't have a vcpu, we move the thread ID into the PACA and we add a kvm pointer to the virtual core structure. In the case where thread 0 has no vcpu to run, it still calls into kvmppc_hv_entry in order to do the MMU switch, and then naps until either its vcpu is ready to run in the guest, or some other thread needs to exit the guest. In the latter case, thread 0 jumps to the code that switches the MMU back to the host. This control flow means that now we switch the MMU before loading any guest vcpu state. Similarly, on guest exit we now save all the guest vcpu state before switching the MMU back to the host. This has required substantial code movement, making the diff rather large. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:20 +08:00
li r0,NAPPING_CEDE
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
stb r0,HSTATE_NAPPING(r13)
lwz r7,VCORE_ENTRY_EXIT(r5)
cmpwi r7,0x100
bge 33f /* another thread already exiting */
/*
* Although not specifically required by the architecture, POWER7
* preserves the following registers in nap mode, even if an SMT mode
* switch occurs: SLB entries, PURR, SPURR, AMOR, UAMOR, AMR, SPRG0-3,
* DAR, DSISR, DABR, DABRX, DSCR, PMCx, MMCRx, SIAR, SDAR.
*/
/* Save non-volatile GPRs */
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
std r14, VCPU_GPR(R14)(r3)
std r15, VCPU_GPR(R15)(r3)
std r16, VCPU_GPR(R16)(r3)
std r17, VCPU_GPR(R17)(r3)
std r18, VCPU_GPR(R18)(r3)
std r19, VCPU_GPR(R19)(r3)
std r20, VCPU_GPR(R20)(r3)
std r21, VCPU_GPR(R21)(r3)
std r22, VCPU_GPR(R22)(r3)
std r23, VCPU_GPR(R23)(r3)
std r24, VCPU_GPR(R24)(r3)
std r25, VCPU_GPR(R25)(r3)
std r26, VCPU_GPR(R26)(r3)
std r27, VCPU_GPR(R27)(r3)
std r28, VCPU_GPR(R28)(r3)
std r29, VCPU_GPR(R29)(r3)
std r30, VCPU_GPR(R30)(r3)
std r31, VCPU_GPR(R31)(r3)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* save FP state */
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
bl kvmppc_save_fp
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
KVM: PPC: Book3S HV: Use decrementer to wake napping threads This arranges for threads that are napping due to their vcpu having ceded or due to not having a vcpu to wake up at the end of the guest's timeslice without having to be poked with an IPI. We do that by arranging for the decrementer to contain a value no greater than the number of timebase ticks remaining until the end of the timeslice. In the case of a thread with no vcpu, this number is in the hypervisor decrementer already. In the case of a ceded vcpu, we use the smaller of the HDEC value and the DEC value. Using the DEC like this when ceded means we need to save and restore the guest decrementer value around the nap. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:08 +08:00
/*
* Set DEC to the smaller of DEC and HDEC, so that we wake
* no later than the end of our timeslice (HDEC interrupts
* don't wake us from nap).
*/
mfspr r3, SPRN_DEC
mfspr r4, SPRN_HDEC
mftb r5
cmpw r3, r4
ble 67f
mtspr SPRN_DEC, r4
67:
/* save expiry time of guest decrementer */
extsw r3, r3
add r3, r3, r5
ld r4, HSTATE_KVM_VCPU(r13)
ld r5, HSTATE_KVM_VCORE(r13)
ld r6, VCORE_TB_OFFSET(r5)
subf r3, r6, r3 /* convert to host TB value */
std r3, VCPU_DEC_EXPIRES(r4)
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
ld r4, HSTATE_KVM_VCPU(r13)
addi r3, r4, VCPU_TB_CEDE
bl kvmhv_accumulate_time
#endif
KVM: PPC: Book3S HV: Don't wake thread with no vcpu on guest IPI When running a multi-threaded guest and vcpu 0 in a virtual core is not running in the guest (i.e. it is busy elsewhere in the host), thread 0 of the physical core will switch the MMU to the guest and then go to nap mode in the code at kvm_do_nap. If the guest sends an IPI to thread 0 using the msgsndp instruction, that will wake up thread 0 and cause all the threads in the guest to exit to the host unnecessarily. To avoid the unnecessary exit, this arranges for the PECEDP bit to be cleared in this situation. When napping due to a H_CEDE from the guest, we still set PECEDP so that the thread will wake up on an IPI sent using msgsndp. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:07 +08:00
lis r3, LPCR_PECEDP@h /* Do wake on privileged doorbell */
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/*
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs * SRR1 wake reason field for system reset interrupt on wakeup from nap is now a 4-bit field on P8, compared to 3 bits on P7. * Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells will wake us up. * Waking up from nap because of a guest doorbell interrupt is not a reason to exit the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:26 +08:00
* Take a nap until a decrementer or external or doobell interrupt
KVM: PPC: Book3S HV: Don't wake thread with no vcpu on guest IPI When running a multi-threaded guest and vcpu 0 in a virtual core is not running in the guest (i.e. it is busy elsewhere in the host), thread 0 of the physical core will switch the MMU to the guest and then go to nap mode in the code at kvm_do_nap. If the guest sends an IPI to thread 0 using the msgsndp instruction, that will wake up thread 0 and cause all the threads in the guest to exit to the host unnecessarily. To avoid the unnecessary exit, this arranges for the PECEDP bit to be cleared in this situation. When napping due to a H_CEDE from the guest, we still set PECEDP so that the thread will wake up on an IPI sent using msgsndp. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:07 +08:00
* occurs, with PECE1 and PECE0 set in LPCR.
KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 This uses msgsnd where possible for signalling other threads within the same core on POWER8 systems, rather than IPIs through the XICS interrupt controller. This includes waking secondary threads to run the guest, the interrupts generated by the virtual XICS, and the interrupts to bring the other threads out of the guest when exiting. Aggregated statistics from debugfs across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, show this before the change: rm_entry: 3387.6ns (228 - 86600, 1008969 samples) rm_exit: 4561.5ns (12 - 3477452, 1009402 samples) rm_intr: 1660.0ns (12 - 553050, 3600051 samples) and this after the change: rm_entry: 3060.1ns (212 - 65138, 953873 samples) rm_exit: 4244.1ns (12 - 9693408, 954331 samples) rm_intr: 1342.3ns (12 - 1104718, 3405326 samples) for a test of booting Fedora 20 big-endian to the login prompt. The time taken for a H_PROD hcall (which is handled in the host kernel) went down from about 35 microseconds to about 16 microseconds with this change. The noinline added to kvmppc_run_core turned out to be necessary for good performance, at least with gcc 4.9.2 as packaged with Fedora 21 and a little-endian POWER8 host. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:12 +08:00
* On POWER8, set PECEDH, and if we are ceding, also set PECEDP.
KVM: PPC: Book3S HV: Don't wake thread with no vcpu on guest IPI When running a multi-threaded guest and vcpu 0 in a virtual core is not running in the guest (i.e. it is busy elsewhere in the host), thread 0 of the physical core will switch the MMU to the guest and then go to nap mode in the code at kvm_do_nap. If the guest sends an IPI to thread 0 using the msgsndp instruction, that will wake up thread 0 and cause all the threads in the guest to exit to the host unnecessarily. To avoid the unnecessary exit, this arranges for the PECEDP bit to be cleared in this situation. When napping due to a H_CEDE from the guest, we still set PECEDP so that the thread will wake up on an IPI sent using msgsndp. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:07 +08:00
* Also clear the runlatch bit before napping.
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
*/
powerpc/powernv: Return to cpu offline loop when finished in KVM guest When a secondary hardware thread has finished running a KVM guest, we currently put that thread into nap mode using a nap instruction in the KVM code. This changes the code so that instead of doing a nap instruction directly, we instead cause the call to power7_nap() that put the thread into nap mode to return. The reason for doing this is to avoid having the KVM code having to know what low-power mode to put the thread into. In the case of a secondary thread used to run a KVM guest, the thread will be offline from the point of view of the host kernel, and the relevant power7_nap() call is the one in pnv_smp_cpu_disable(). In this case we don't want to clear pending IPIs in the offline loop in that function, since that might cause us to miss the wakeup for the next time the thread needs to run a guest. To tell whether or not to clear the interrupt, we use the SRR1 value returned from power7_nap(), and check if it indicates an external interrupt. We arrange that the return from power7_nap() when we have finished running a guest returns 0, so pending interrupts don't get flushed in that case. Note that it is important a secondary thread that has finished executing in the guest, or that didn't have a guest to run, should not return to power7_nap's caller while the kvm_hstate.hwthread_req flag in the PACA is non-zero, because the return from power7_nap will reenable the MMU, and the MMU might still be in guest context. In this situation we spin at low priority in real mode waiting for hwthread_req to become zero. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-03 11:48:40 +08:00
kvm_do_nap:
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
mfspr r0, SPRN_CTRLF
clrrdi r0, r0, 1
mtspr SPRN_CTRLT, r0
ppc/kvm: Clear the runlatch bit of a vcpu before napping When the guest cedes the vcpu or the vcpu has no guest to run it naps. Clear the runlatch bit of the vcpu before napping to indicate an idle cpu. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-04-11 18:32:08 +08:00
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
li r0,1
stb r0,HSTATE_HWTHREAD_REQ(r13)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
mfspr r5,SPRN_LPCR
ori r5,r5,LPCR_PECE0 | LPCR_PECE1
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs * SRR1 wake reason field for system reset interrupt on wakeup from nap is now a 4-bit field on P8, compared to 3 bits on P7. * Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells will wake us up. * Waking up from nap because of a guest doorbell interrupt is not a reason to exit the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:26 +08:00
BEGIN_FTR_SECTION
KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 This uses msgsnd where possible for signalling other threads within the same core on POWER8 systems, rather than IPIs through the XICS interrupt controller. This includes waking secondary threads to run the guest, the interrupts generated by the virtual XICS, and the interrupts to bring the other threads out of the guest when exiting. Aggregated statistics from debugfs across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, show this before the change: rm_entry: 3387.6ns (228 - 86600, 1008969 samples) rm_exit: 4561.5ns (12 - 3477452, 1009402 samples) rm_intr: 1660.0ns (12 - 553050, 3600051 samples) and this after the change: rm_entry: 3060.1ns (212 - 65138, 953873 samples) rm_exit: 4244.1ns (12 - 9693408, 954331 samples) rm_intr: 1342.3ns (12 - 1104718, 3405326 samples) for a test of booting Fedora 20 big-endian to the login prompt. The time taken for a H_PROD hcall (which is handled in the host kernel) went down from about 35 microseconds to about 16 microseconds with this change. The noinline added to kvmppc_run_core turned out to be necessary for good performance, at least with gcc 4.9.2 as packaged with Fedora 21 and a little-endian POWER8 host. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:12 +08:00
ori r5, r5, LPCR_PECEDH
KVM: PPC: Book3S HV: Don't wake thread with no vcpu on guest IPI When running a multi-threaded guest and vcpu 0 in a virtual core is not running in the guest (i.e. it is busy elsewhere in the host), thread 0 of the physical core will switch the MMU to the guest and then go to nap mode in the code at kvm_do_nap. If the guest sends an IPI to thread 0 using the msgsndp instruction, that will wake up thread 0 and cause all the threads in the guest to exit to the host unnecessarily. To avoid the unnecessary exit, this arranges for the PECEDP bit to be cleared in this situation. When napping due to a H_CEDE from the guest, we still set PECEDP so that the thread will wake up on an IPI sent using msgsndp. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:07 +08:00
rlwimi r5, r3, 0, LPCR_PECEDP
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs * SRR1 wake reason field for system reset interrupt on wakeup from nap is now a 4-bit field on P8, compared to 3 bits on P7. * Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells will wake us up. * Waking up from nap because of a guest doorbell interrupt is not a reason to exit the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:26 +08:00
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
mtspr SPRN_LPCR,r5
isync
li r0, 0
std r0, HSTATE_SCRATCH0(r13)
ptesync
ld r0, HSTATE_SCRATCH0(r13)
1: cmpd r0, r0
bne 1b
nap
b .
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
33: mr r4, r3
li r3, 0
li r12, 0
b 34f
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
kvm_end_cede:
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
/* get vcpu pointer */
ld r4, HSTATE_KVM_VCPU(r13)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* Woken by external or decrementer interrupt */
ld r1, HSTATE_HOST_R1(r13)
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
addi r3, r4, VCPU_TB_RMINTR
bl kvmhv_accumulate_time
#endif
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* load up FP state */
bl kvmppc_load_fp
KVM: PPC: Book3S HV: Use decrementer to wake napping threads This arranges for threads that are napping due to their vcpu having ceded or due to not having a vcpu to wake up at the end of the guest's timeslice without having to be poked with an IPI. We do that by arranging for the decrementer to contain a value no greater than the number of timebase ticks remaining until the end of the timeslice. In the case of a thread with no vcpu, this number is in the hypervisor decrementer already. In the case of a ceded vcpu, we use the smaller of the HDEC value and the DEC value. Using the DEC like this when ceded means we need to save and restore the guest decrementer value around the nap. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:08 +08:00
/* Restore guest decrementer */
ld r3, VCPU_DEC_EXPIRES(r4)
ld r5, HSTATE_KVM_VCORE(r13)
ld r6, VCORE_TB_OFFSET(r5)
add r3, r3, r6 /* convert host TB to guest TB value */
mftb r7
subf r3, r7, r3
mtspr SPRN_DEC, r3
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* Load NV GPRS */
powerpc: Fix usage of register macros getting ready for %r0 change Anything that uses a constructed instruction (ie. from ppc-opcode.h), need to use the new R0 macro, as %r0 is not going to work. Also convert usages of macros where we are just determining an offset (usually for a load/store), like: std r14,STK_REG(r14)(r1) Can't use STK_REG(r14) as %r14 doesn't work in the STK_REG macro since it's just calculating an offset. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-06-25 21:33:10 +08:00
ld r14, VCPU_GPR(R14)(r4)
ld r15, VCPU_GPR(R15)(r4)
ld r16, VCPU_GPR(R16)(r4)
ld r17, VCPU_GPR(R17)(r4)
ld r18, VCPU_GPR(R18)(r4)
ld r19, VCPU_GPR(R19)(r4)
ld r20, VCPU_GPR(R20)(r4)
ld r21, VCPU_GPR(R21)(r4)
ld r22, VCPU_GPR(R22)(r4)
ld r23, VCPU_GPR(R23)(r4)
ld r24, VCPU_GPR(R24)(r4)
ld r25, VCPU_GPR(R25)(r4)
ld r26, VCPU_GPR(R26)(r4)
ld r27, VCPU_GPR(R27)(r4)
ld r28, VCPU_GPR(R28)(r4)
ld r29, VCPU_GPR(R29)(r4)
ld r30, VCPU_GPR(R30)(r4)
ld r31, VCPU_GPR(R31)(r4)
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
/* Check the wake reason in SRR1 to see why we got here */
bl kvmppc_check_wake_reason
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* clear our bit in vcore->napping_threads */
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
34: ld r5,HSTATE_KVM_VCORE(r13)
lbz r7,HSTATE_PTID(r13)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
li r0,1
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
sld r0,r0,r7
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
addi r6,r5,VCORE_NAPPING_THREADS
32: lwarx r7,0,r6
andc r7,r7,r0
stwcx. r7,0,r6
bne 32b
li r0,0
stb r0,HSTATE_NAPPING(r13)
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
/* See if the wake reason means we need to exit */
stw r12, VCPU_TRAP(r4)
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
mr r9, r4
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
cmpdi r3, 0
bgt guest_exit_cont
KVM: PPC: Book3S HV: Improve real-mode handling of external interrupts This streamlines our handling of external interrupts that come in while we're in the guest. First, when waking up a hardware thread that was napping, we split off the "napping due to H_CEDE" case earlier, and use the code that handles an external interrupt (0x500) in the guest to handle that too. Secondly, the code that handles those external interrupts now checks if any other thread is exiting to the host before bouncing an external interrupt to the guest, and also checks that there is actually an external interrupt pending for the guest before setting the LPCR MER bit (mediated external request). This also makes sure that we clear the "ceded" flag when we handle a wakeup from cede in real mode, and fixes a potential infinite loop in kvmppc_run_vcpu() which can occur if we ever end up with the ceded flag set but MSR[EE] off. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-18 04:31:41 +08:00
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* see if any other thread is already exiting */
lwz r0,VCORE_ENTRY_EXIT(r5)
cmpwi r0,0x100
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
bge guest_exit_cont
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
b kvmppc_cede_reentry /* if not go back to guest */
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
/* cede when already previously prodded case */
KVM: PPC: Book3S HV: Fix incorrect branch in H_CEDE code In handling the H_CEDE hypercall, if this vcpu has already been prodded (with the H_PROD hypercall, which Linux guests don't in fact use), we branch to a numeric label '1f'. Unfortunately there is another '1:' label before the one that we want to jump to. This fixes the problem by using a textual label, 'kvm_cede_prodded'. It also changes the label for another longish branch from '2:' to 'kvm_cede_exit' to avoid a possible future problem if code modifications add another numeric '2:' label in between. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-08-06 08:03:28 +08:00
kvm_cede_prodded:
li r0,0
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
stb r0,VCPU_PRODDED(r3)
sync /* order testing prodded vs. clearing ceded */
stb r0,VCPU_CEDED(r3)
li r3,H_SUCCESS
blr
/* we've ceded but we want to give control to the host */
KVM: PPC: Book3S HV: Fix incorrect branch in H_CEDE code In handling the H_CEDE hypercall, if this vcpu has already been prodded (with the H_PROD hypercall, which Linux guests don't in fact use), we branch to a numeric label '1f'. Unfortunately there is another '1:' label before the one that we want to jump to. This fixes the problem by using a textual label, 'kvm_cede_prodded'. It also changes the label for another longish branch from '2:' to 'kvm_cede_exit' to avoid a possible future problem if code modifications add another numeric '2:' label in between. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2012-08-06 08:03:28 +08:00
kvm_cede_exit:
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
ld r9, HSTATE_KVM_VCPU(r13)
b guest_exit_cont
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
/* Try to handle a machine check in real mode */
machine_check_realmode:
mr r3, r9 /* get vcpu pointer */
powerpc: No need to use dot symbols when branching to a function binutils is smart enough to know that a branch to a function descriptor is actually a branch to the functions text address. Alan tells me that binutils has been doing this for 9 years. Signed-off-by: Anton Blanchard <anton@samba.org>
2014-02-04 13:04:35 +08:00
bl kvmppc_realmode_machine_check
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
nop
powerpc/book3s: Fix guest MC delivery mechanism to avoid soft lockups in guest. Currently we forward MCEs to guest which have been recovered by guest. And for unhandled errors we do not deliver the MCE to guest. It looks like with no support of FWNMI in qemu, guest just panics whenever we deliver the recovered MCEs to guest. Also, the existig code used to return to host for unhandled errors which was casuing guest to hang with soft lockups inside guest and makes it difficult to recover guest instance. This patch now forwards all fatal MCEs to guest causing guest to crash/panic. And, for recovered errors we just go back to normal functioning of guest instead of returning to host. This fixes soft lockup issues in guest. This patch also fixes an issue where guest MCE events were not logged to host console. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-06-11 16:48:21 +08:00
cmpdi r3, 0 /* Did we handle MCE ? */
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
ld r9, HSTATE_KVM_VCPU(r13)
li r12, BOOK3S_INTERRUPT_MACHINE_CHECK
powerpc/book3s: Fix guest MC delivery mechanism to avoid soft lockups in guest. Currently we forward MCEs to guest which have been recovered by guest. And for unhandled errors we do not deliver the MCE to guest. It looks like with no support of FWNMI in qemu, guest just panics whenever we deliver the recovered MCEs to guest. Also, the existig code used to return to host for unhandled errors which was casuing guest to hang with soft lockups inside guest and makes it difficult to recover guest instance. This patch now forwards all fatal MCEs to guest causing guest to crash/panic. And, for recovered errors we just go back to normal functioning of guest instead of returning to host. This fixes soft lockup issues in guest. This patch also fixes an issue where guest MCE events were not logged to host console. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-06-11 16:48:21 +08:00
/*
* Deliver unhandled/fatal (e.g. UE) MCE errors to guest through
* machine check interrupt (set HSRR0 to 0x200). And for handled
* errors (no-fatal), just go back to guest execution with current
* HSRR0 instead of exiting guest. This new approach will inject
* machine check to guest for fatal error causing guest to crash.
*
* The old code used to return to host for unhandled errors which
* was causing guest to hang with soft lockups inside guest and
* makes it difficult to recover guest instance.
*/
ld r10, VCPU_PC(r9)
ld r11, VCPU_MSR(r9)
bne 2f /* Continue guest execution. */
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
/* If not, deliver a machine check. SRR0/1 are already set */
li r10, BOOK3S_INTERRUPT_MACHINE_CHECK
KVM: PPC: Book3S HV: Fix machine check delivery to guest The code that delivered a machine check to the guest after handling it in real mode failed to load up r11 before calling kvmppc_msr_interrupt, which needs the old MSR value in r11 so it can see the transactional state there. This adds the missing load. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-26 17:48:41 +08:00
ld r11, VCPU_MSR(r9)
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
bl kvmppc_msr_interrupt
powerpc/book3s: Fix guest MC delivery mechanism to avoid soft lockups in guest. Currently we forward MCEs to guest which have been recovered by guest. And for unhandled errors we do not deliver the MCE to guest. It looks like with no support of FWNMI in qemu, guest just panics whenever we deliver the recovered MCEs to guest. Also, the existig code used to return to host for unhandled errors which was casuing guest to hang with soft lockups inside guest and makes it difficult to recover guest instance. This patch now forwards all fatal MCEs to guest causing guest to crash/panic. And, for recovered errors we just go back to normal functioning of guest instead of returning to host. This fixes soft lockup issues in guest. This patch also fixes an issue where guest MCE events were not logged to host console. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-06-11 16:48:21 +08:00
2: b fast_interrupt_c_return
KVM: PPC: Book3S HV: Handle guest-caused machine checks on POWER7 without panicking Currently, if a machine check interrupt happens while we are in the guest, we exit the guest and call the host's machine check handler, which tends to cause the host to panic. Some machine checks can be triggered by the guest; for example, if the guest creates two entries in the SLB that map the same effective address, and then accesses that effective address, the CPU will take a machine check interrupt. To handle this better, when a machine check happens inside the guest, we call a new function, kvmppc_realmode_machine_check(), while still in real mode before exiting the guest. On POWER7, it handles the cases that the guest can trigger, either by flushing and reloading the SLB, or by flushing the TLB, and then it delivers the machine check interrupt directly to the guest without going back to the host. On POWER7, the OPAL firmware patches the machine check interrupt vector so that it gets control first, and it leaves behind its analysis of the situation in a structure pointed to by the opal_mc_evt field of the paca. The kvmppc_realmode_machine_check() function looks at this, and if OPAL reports that there was no error, or that it has handled the error, we also go straight back to the guest with a machine check. We have to deliver a machine check to the guest since the machine check interrupt might have trashed valid values in SRR0/1. If the machine check is one we can't handle in real mode, and one that OPAL hasn't already handled, or on PPC970, we exit the guest and call the host's machine check handler. We do this by jumping to the machine_check_fwnmi label, rather than absolute address 0x200, because we don't want to re-execute OPAL's handler on POWER7. On PPC970, the two are equivalent because address 0x200 just contains a branch. Then, if the host machine check handler decides that the system can continue executing, kvmppc_handle_exit() delivers a machine check interrupt to the guest -- once again to let the guest know that SRR0/1 have been modified. Signed-off-by: Paul Mackerras <paulus@samba.org> [agraf: fix checkpatch warnings] Signed-off-by: Alexander Graf <agraf@suse.de>
2012-11-24 06:37:50 +08:00
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
/*
* Check the reason we woke from nap, and take appropriate action.
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
* Returns (in r3):
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
* 0 if nothing needs to be done
* 1 if something happened that needs to be handled by the host
KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 This uses msgsnd where possible for signalling other threads within the same core on POWER8 systems, rather than IPIs through the XICS interrupt controller. This includes waking secondary threads to run the guest, the interrupts generated by the virtual XICS, and the interrupts to bring the other threads out of the guest when exiting. Aggregated statistics from debugfs across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, show this before the change: rm_entry: 3387.6ns (228 - 86600, 1008969 samples) rm_exit: 4561.5ns (12 - 3477452, 1009402 samples) rm_intr: 1660.0ns (12 - 553050, 3600051 samples) and this after the change: rm_entry: 3060.1ns (212 - 65138, 953873 samples) rm_exit: 4244.1ns (12 - 9693408, 954331 samples) rm_intr: 1342.3ns (12 - 1104718, 3405326 samples) for a test of booting Fedora 20 big-endian to the login prompt. The time taken for a H_PROD hcall (which is handled in the host kernel) went down from about 35 microseconds to about 16 microseconds with this change. The noinline added to kvmppc_run_core turned out to be necessary for good performance, at least with gcc 4.9.2 as packaged with Fedora 21 and a little-endian POWER8 host. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:12 +08:00
* -1 if there was a guest wakeup (IPI or msgsnd)
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
*
* Also sets r12 to the interrupt vector for any interrupt that needs
* to be handled now by the host (0x500 for external interrupt), or zero.
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
* Modifies r0, r6, r7, r8.
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
*/
kvmppc_check_wake_reason:
mfspr r6, SPRN_SRR1
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs * SRR1 wake reason field for system reset interrupt on wakeup from nap is now a 4-bit field on P8, compared to 3 bits on P7. * Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells will wake us up. * Waking up from nap because of a guest doorbell interrupt is not a reason to exit the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:26 +08:00
BEGIN_FTR_SECTION
rlwinm r6, r6, 45-31, 0xf /* extract wake reason field (P8) */
FTR_SECTION_ELSE
rlwinm r6, r6, 45-31, 0xe /* P7 wake reason field is 3 bits */
ALT_FTR_SECTION_END_IFSET(CPU_FTR_ARCH_207S)
cmpwi r6, 8 /* was it an external interrupt? */
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
li r12, BOOK3S_INTERRUPT_EXTERNAL
beq kvmppc_read_intr /* if so, see what it was */
li r3, 0
li r12, 0
cmpwi r6, 6 /* was it the decrementer? */
beq 0f
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs * SRR1 wake reason field for system reset interrupt on wakeup from nap is now a 4-bit field on P8, compared to 3 bits on P7. * Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells will wake us up. * Waking up from nap because of a guest doorbell interrupt is not a reason to exit the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:26 +08:00
BEGIN_FTR_SECTION
cmpwi r6, 5 /* privileged doorbell? */
beq 0f
KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells POWER8 has support for hypervisor doorbell interrupts. Though the kernel doesn't use them for IPIs on the powernv platform yet, it probably will in future, so this makes KVM cope gracefully if a hypervisor doorbell interrupt arrives while in a guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:28 +08:00
cmpwi r6, 3 /* hypervisor doorbell? */
beq 3f
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs * SRR1 wake reason field for system reset interrupt on wakeup from nap is now a 4-bit field on P8, compared to 3 bits on P7. * Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells will wake us up. * Waking up from nap because of a guest doorbell interrupt is not a reason to exit the guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:26 +08:00
END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
li r3, 1 /* anything else, return 1 */
0: blr
KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells POWER8 has support for hypervisor doorbell interrupts. Though the kernel doesn't use them for IPIs on the powernv platform yet, it probably will in future, so this makes KVM cope gracefully if a hypervisor doorbell interrupt arrives while in a guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:28 +08:00
/* hypervisor doorbell */
3: li r12, BOOK3S_INTERRUPT_H_DOORBELL
KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 This uses msgsnd where possible for signalling other threads within the same core on POWER8 systems, rather than IPIs through the XICS interrupt controller. This includes waking secondary threads to run the guest, the interrupts generated by the virtual XICS, and the interrupts to bring the other threads out of the guest when exiting. Aggregated statistics from debugfs across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, show this before the change: rm_entry: 3387.6ns (228 - 86600, 1008969 samples) rm_exit: 4561.5ns (12 - 3477452, 1009402 samples) rm_intr: 1660.0ns (12 - 553050, 3600051 samples) and this after the change: rm_entry: 3060.1ns (212 - 65138, 953873 samples) rm_exit: 4244.1ns (12 - 9693408, 954331 samples) rm_intr: 1342.3ns (12 - 1104718, 3405326 samples) for a test of booting Fedora 20 big-endian to the login prompt. The time taken for a H_PROD hcall (which is handled in the host kernel) went down from about 35 microseconds to about 16 microseconds with this change. The noinline added to kvmppc_run_core turned out to be necessary for good performance, at least with gcc 4.9.2 as packaged with Fedora 21 and a little-endian POWER8 host. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:12 +08:00
/* see if it's a host IPI */
KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells POWER8 has support for hypervisor doorbell interrupts. Though the kernel doesn't use them for IPIs on the powernv platform yet, it probably will in future, so this makes KVM cope gracefully if a hypervisor doorbell interrupt arrives while in a guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:28 +08:00
li r3, 1
KVM: PPC: Book3S HV: Use msgsnd for signalling threads on POWER8 This uses msgsnd where possible for signalling other threads within the same core on POWER8 systems, rather than IPIs through the XICS interrupt controller. This includes waking secondary threads to run the guest, the interrupts generated by the virtual XICS, and the interrupts to bring the other threads out of the guest when exiting. Aggregated statistics from debugfs across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, show this before the change: rm_entry: 3387.6ns (228 - 86600, 1008969 samples) rm_exit: 4561.5ns (12 - 3477452, 1009402 samples) rm_intr: 1660.0ns (12 - 553050, 3600051 samples) and this after the change: rm_entry: 3060.1ns (212 - 65138, 953873 samples) rm_exit: 4244.1ns (12 - 9693408, 954331 samples) rm_intr: 1342.3ns (12 - 1104718, 3405326 samples) for a test of booting Fedora 20 big-endian to the login prompt. The time taken for a H_PROD hcall (which is handled in the host kernel) went down from about 35 microseconds to about 16 microseconds with this change. The noinline added to kvmppc_run_core turned out to be necessary for good performance, at least with gcc 4.9.2 as packaged with Fedora 21 and a little-endian POWER8 host. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:12 +08:00
lbz r0, HSTATE_HOST_IPI(r13)
cmpwi r0, 0
bnelr
/* if not, clear it and return -1 */
lis r6, (PPC_DBELL_SERVER << (63-36))@h
PPC_MSGCLR(6)
li r3, -1
KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells POWER8 has support for hypervisor doorbell interrupts. Though the kernel doesn't use them for IPIs on the powernv platform yet, it probably will in future, so this makes KVM cope gracefully if a hypervisor doorbell interrupt arrives while in a guest. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:28 +08:00
blr
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
/*
* Determine what sort of external interrupt is pending (if any).
* Returns:
* 0 if no interrupt is pending
* 1 if an interrupt is pending that needs to be handled by the host
* -1 if there was a guest wakeup IPI (which has now been cleared)
KVM: PPC: Book3S HV: Minor cleanups * Remove unused kvmppc_vcore::n_busy field. * Remove setting of RMOR, since it was only used on PPC970 and the PPC970 KVM support has been removed. * Don't use r1 or r2 in setting the runlatch since they are conventionally reserved for other things; use r0 instead. * Streamline the code a little and remove the ext_interrupt_to_host label. * Add some comments about register usage. * hcall_try_real_mode doesn't need to be global, and can't be called from C code anyway. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:04 +08:00
* Modifies r0, r6, r7, r8, returns value in r3.
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
*/
kvmppc_read_intr:
/* see if a host IPI is pending */
li r3, 1
lbz r0, HSTATE_HOST_IPI(r13)
cmpwi r0, 0
bne 1f
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
/* Now read the interrupt from the ICP */
ld r6, HSTATE_XICS_PHYS(r13)
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
li r7, XICS_XIRR
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
cmpdi r6, 0
beq- 1f
lwzcix r0, r6, r7
KVM: PPC: Book3S HV: Access XICS in BE On the exit path from the guest we check what type of interrupt we received if we received one. This means we're doing hardware access to the XICS interrupt controller. However, when running on a little endian system, this access is byte reversed. So let's make sure to swizzle the bytes back again and virtually make XICS accesses big endian. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-11 16:37:52 +08:00
/*
* Save XIRR for later. Since we get in in reverse endian on LE
* systems, save it byte reversed and fetch it back in host endian.
*/
li r3, HSTATE_SAVED_XIRR
STWX_BE r0, r3, r13
#ifdef __LITTLE_ENDIAN__
lwz r3, HSTATE_SAVED_XIRR(r13)
#else
mr r3, r0
#endif
rlwinm. r3, r3, 0, 0xffffff
KVM: PPC: Implement H_CEDE hcall for book3s_hv in real-mode code With a KVM guest operating in SMT4 mode (i.e. 4 hardware threads per core), whenever a CPU goes idle, we have to pull all the other hardware threads in the core out of the guest, because the H_CEDE hcall is handled in the kernel. This is inefficient. This adds code to book3s_hv_rmhandlers.S to handle the H_CEDE hcall in real mode. When a guest vcpu does an H_CEDE hcall, we now only exit to the kernel if all the other vcpus in the same core are also idle. Otherwise we mark this vcpu as napping, save state that could be lost in nap mode (mainly GPRs and FPRs), and execute the nap instruction. When the thread wakes up, because of a decrementer or external interrupt, we come back in at kvm_start_guest (from the system reset interrupt vector), find the `napping' flag set in the paca, and go to the resume path. This has some other ramifications. First, when starting a core, we now start all the threads, both those that are immediately runnable and those that are idle. This is so that we don't have to pull all the threads out of the guest when an idle thread gets a decrementer interrupt and wants to start running. In fact the idle threads will all start with the H_CEDE hcall returning; being idle they will just do another H_CEDE immediately and go to nap mode. This required some changes to kvmppc_run_core() and kvmppc_run_vcpu(). These functions have been restructured to make them simpler and clearer. We introduce a level of indirection in the wait queue that gets woken when external and decrementer interrupts get generated for a vcpu, so that we can have the 4 vcpus in a vcore using the same wait queue. We need this because the 4 vcpus are being handled by one thread. Secondly, when we need to exit from the guest to the kernel, we now have to generate an IPI for any napping threads, because an HDEC interrupt doesn't wake up a napping thread. Thirdly, we now need to be able to handle virtual external interrupts and decrementer interrupts becoming pending while a thread is napping, and deliver those interrupts to the guest when the thread wakes. This is done in kvmppc_cede_reentry, just before fast_guest_return. Finally, since we are not using the generic kvm_vcpu_block for book3s_hv, and hence not calling kvm_arch_vcpu_runnable, we can remove the #ifdef from kvm_arch_vcpu_runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-07-23 15:42:46 +08:00
sync
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
beq 1f /* if nothing pending in the ICP */
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
/* We found something in the ICP...
*
* If it's not an IPI, stash it in the PACA and return to
* the host, we don't (yet) handle directing real external
* interrupts directly to the guest
*/
cmpwi r3, XICS_IPI /* if there is, is it an IPI? */
bne 42f
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
/* It's an IPI, clear the MFRR and EOI it */
li r3, 0xff
li r8, XICS_MFRR
stbcix r3, r6, r8 /* clear the IPI */
stwcix r0, r6, r7 /* EOI it */
sync
KVM: PPC: Book3S HV: Make secondary threads more robust against stray IPIs Currently on POWER7, if we are running the guest on a core and we don't need all the hardware threads, we do nothing to ensure that the unused threads aren't executing in the kernel (other than checking that they are offline). We just assume they're napping and we don't do anything to stop them trying to enter the kernel while the guest is running. This means that a stray IPI can wake up the hardware thread and it will then try to enter the kernel, but since the core is in guest context, it will execute code from the guest in hypervisor mode once it turns the MMU on, which tends to lead to crashes or hangs in the host. This fixes the problem by adding two new one-byte flags in the kvmppc_host_state structure in the PACA which are used to interlock between the primary thread and the unused secondary threads when entering the guest. With these flags, the primary thread can ensure that the unused secondaries are not already in kernel mode (i.e. handling a stray IPI) and then indicate that they should not try to enter the kernel if they do get woken for any reason. Instead they will go into KVM code, find that there is no vcpu to run, acknowledge and clear the IPI and go back to nap mode. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-03 08:54:17 +08:00
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
/* We need to re-check host IPI now in case it got set in the
* meantime. If it's clear, we bounce the interrupt to the
* guest
*/
lbz r0, HSTATE_HOST_IPI(r13)
cmpwi r0, 0
bne- 43f
/* OK, it's an IPI for us */
KVM: PPC: Book3S HV: Streamline guest entry and exit On entry to the guest, secondary threads now wait for the primary to switch the MMU after loading up most of their state, rather than before. This means that the secondary threads get into the guest sooner, in the common case where the secondary threads get to kvmppc_hv_entry before the primary thread. On exit, the first thread out increments the exit count and interrupts the other threads (to get them out of the guest) before saving most of its state, rather than after. That means that the other threads exit sooner and means that the first thread doesn't spend so much time waiting for the other threads at the point where the MMU gets switched back to the host. This pulls out the code that increments the exit count and interrupts other threads into a separate function, kvmhv_commence_exit(). This also makes sure that r12 and vcpu->arch.trap are set correctly in some corner cases. Statistics from /sys/kernel/debug/kvm/vm*/vcpu*/timings show the improvement. Aggregating across vcpus for a guest with 32 vcpus, 8 threads/vcore, running on a POWER8, gives this before the change: rm_entry: avg 4537.3ns (222 - 48444, 1068878 samples) rm_exit: avg 4787.6ns (152 - 165490, 1010717 samples) rm_intr: avg 1673.6ns (12 - 341304, 3818691 samples) and this after the change: rm_entry: avg 3427.7ns (232 - 68150, 1118921 samples) rm_exit: avg 4716.0ns (12 - 150720, 1119477 samples) rm_intr: avg 1614.8ns (12 - 522436, 3850432 samples) showing a substantial reduction in the time spent per guest entry in the real-mode guest entry code, and smaller reductions in the real mode guest exit and interrupt handling times. (The test was to start the guest and boot Fedora 20 big-endian to the login prompt.) Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:10 +08:00
li r12, 0
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
li r3, -1
1: blr
KVM: PPC: Book3S HV: Access XICS in BE On the exit path from the guest we check what type of interrupt we received if we received one. This means we're doing hardware access to the XICS interrupt controller. However, when running on a little endian system, this access is byte reversed. So let's make sure to swizzle the bytes back again and virtually make XICS accesses big endian. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-11 16:37:52 +08:00
42: /* It's not an IPI and it's for the host. We saved a copy of XIRR in
* the PACA earlier, it will be picked up by the host ICP driver
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
*/
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
li r3, 1
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
b 1b
43: /* We raced with the host, we need to resend that IPI, bummer */
li r0, IPI_PRIORITY
stbcix r0, r6, r8 /* set the IPI */
sync
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap Currently in book3s_hv_rmhandlers.S we have three places where we have woken up from nap mode and we check the reason field in SRR1 to see what event woke us up. This consolidates them into a new function, kvmppc_check_wake_reason. It looks at the wake reason field in SRR1, and if it indicates that an external interrupt caused the wakeup, calls kvmppc_read_intr to check what sort of interrupt it was. This also consolidates the two places where we synthesize an external interrupt (0x500 vector) for the guest. Now, if the guest exit code finds that there was an external interrupt which has been handled (i.e. it was an IPI indicating that there is now an interrupt pending for the guest), it jumps to deliver_guest_interrupt, which is in the last part of the guest entry code, where we synthesize guest external and decrementer interrupts. That code has been streamlined a little and now clears LPCR[MER] when appropriate as well as setting it. The extra clearing of any pending IPI on a secondary, offline CPU thread before going back to nap mode has been removed. It is no longer necessary now that we have code to read and acknowledge IPIs in the guest exit path. This fixes a minor bug in the H_CEDE real-mode handling - previously, if we found that other threads were already exiting the guest when we were about to go to nap mode, we would branch to the cede wakeup path and end up looking in SRR1 for a wakeup reason. Now we branch to a point after we have checked the wakeup reason. This also fixes a minor bug in kvmppc_read_intr - previously it could return 0xff rather than 1, in the case where we find that a host IPI is pending after we have cleared the IPI. Now it returns 1. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-01-08 18:25:25 +08:00
li r3, 1
KVM: PPC: Book3S HV: Pull out interrupt-reading code into a subroutine This moves the code in book3s_hv_rmhandlers.S that reads any pending interrupt from the XICS interrupt controller, and works out whether it is an IPI for the guest, an IPI for the host, or a device interrupt, into a new function called kvmppc_read_intr. Later patches will need this. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-09-06 11:24:13 +08:00
b 1b
KVM: PPC: Allow book3s_hv guests to use SMT processor modes This lifts the restriction that book3s_hv guests can only run one hardware thread per core, and allows them to use up to 4 threads per core on POWER7. The host still has to run single-threaded. This capability is advertised to qemu through a new KVM_CAP_PPC_SMT capability. The return value of the ioctl querying this capability is the number of vcpus per virtual CPU core (vcore), currently 4. To use this, the host kernel should be booted with all threads active, and then all the secondary threads should be offlined. This will put the secondary threads into nap mode. KVM will then wake them from nap mode and use them for running guest code (while they are still offline). To wake the secondary threads, we send them an IPI using a new xics_wake_cpu() function, implemented in arch/powerpc/sysdev/xics/icp-native.c. In other words, at this stage we assume that the platform has a XICS interrupt controller and we are using icp-native.c to drive it. Since the woken thread will need to acknowledge and clear the IPI, we also export the base physical address of the XICS registers using kvmppc_set_xics_phys() for use in the low-level KVM book3s code. When a vcpu is created, it is assigned to a virtual CPU core. The vcore number is obtained by dividing the vcpu number by the number of threads per core in the host. This number is exported to userspace via the KVM_CAP_PPC_SMT capability. If qemu wishes to run the guest in single-threaded mode, it should make all vcpu numbers be multiples of the number of threads per core. We distinguish three states of a vcpu: runnable (i.e., ready to execute the guest), blocked (that is, idle), and busy in host. We currently implement a policy that the vcore can run only when all its threads are runnable or blocked. This way, if a vcpu needs to execute elsewhere in the kernel or in qemu, it can do so without being starved of CPU by the other vcpus. When a vcore starts to run, it executes in the context of one of the vcpu threads. The other vcpu threads all go to sleep and stay asleep until something happens requiring the vcpu thread to return to qemu, or to wake up to run the vcore (this can happen when another vcpu thread goes from busy in host state to blocked). It can happen that a vcpu goes from blocked to runnable state (e.g. because of an interrupt), and the vcore it belongs to is already running. In that case it can start to run immediately as long as the none of the vcpus in the vcore have started to exit the guest. We send the next free thread in the vcore an IPI to get it to start to execute the guest. It synchronizes with the other threads via the vcore->entry_exit_count field to make sure that it doesn't go into the guest if the other vcpus are exiting by the time that it is ready to actually enter the guest. Note that there is no fixed relationship between the hardware thread number and the vcpu number. Hardware threads are assigned to vcpus as they become runnable, so we will always use the lower-numbered hardware threads in preference to higher-numbered threads if not all the vcpus in the vcore are runnable, regardless of which vcpus are runnable. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:23:08 +08:00
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
/*
* Save away FP, VMX and VSX registers.
* r3 = vcpu pointer
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
* N.B. r30 and r31 are volatile across this function,
* thus it is not callable from C.
KVM: PPC: Handle some PAPR hcalls in the kernel This adds the infrastructure for handling PAPR hcalls in the kernel, either early in the guest exit path while we are still in real mode, or later once the MMU has been turned back on and we are in the full kernel context. The advantage of handling hcalls in real mode if possible is that we avoid two partition switches -- and this will become more important when we support SMT4 guests, since a partition switch means we have to pull all of the threads in the core out of the guest. The disadvantage is that we can only access the kernel linear mapping, not anything vmalloced or ioremapped, since the MMU is off. This also adds code to handle the following hcalls in real mode: H_ENTER Add an HPTE to the hashed page table H_REMOVE Remove an HPTE from the hashed page table H_READ Read HPTEs from the hashed page table H_PROTECT Change the protection bits in an HPTE H_BULK_REMOVE Remove up to 4 HPTEs from the hashed page table H_SET_DABR Set the data address breakpoint register Plus code to handle the following hcalls in the kernel: H_CEDE Idle the vcpu until an interrupt or H_PROD hcall arrives H_PROD Wake up a ceded vcpu H_REGISTER_VPA Register a virtual processor area (VPA) The code that runs in real mode has to be in the base kernel, not in the module, if KVM is compiled as a module. The real-mode code can only access the kernel linear mapping, not vmalloc or ioremap space. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:22:05 +08:00
*/
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
kvmppc_save_fp:
mflr r30
mr r31,r3
KVM: PPC: Work around POWER7 DABR corruption problem It turns out that on POWER7, writing to the DABR can cause a corrupted value to be written if the PMU is active and updating SDAR in continuous sampling mode. To work around this, we make sure that the PMU is inactive and SDAR updates are disabled (via MMCRA) when we are context-switching DABR. When the guest sets DABR via the H_SET_DABR hypercall, we use a slightly different workaround, which is to read back the DABR and write it again if it got corrupted. While we are at it, make it consistent that the saving and restoring of the guest's non-volatile GPRs and the FPRs are done with the guest setup of the PMU active. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-02 09:38:23 +08:00
mfmsr r5
ori r8,r5,MSR_FP
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
oris r8,r8,MSR_VEC@h
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
#ifdef CONFIG_VSX
BEGIN_FTR_SECTION
oris r8,r8,MSR_VSX@h
END_FTR_SECTION_IFSET(CPU_FTR_VSX)
#endif
mtmsrd r8
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
addi r3,r3,VCPU_FPRS
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl store_fp_state
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
addi r3,r31,VCPU_VRS
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl store_vr_state
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
mfspr r6,SPRN_VRSAVE
KVM: PPC: Book3S HV: Fix register usage when loading/saving VRSAVE Commit 595e4f7e697e ("KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit") changed the register usage in kvmppc_save_fp() and kvmppc_load_fp() but omitted changing the instructions that load and save VRSAVE. The result is that the VRSAVE value was loaded from a constant address, and saved to a location past the end of the vcpu struct, causing host kernel memory corruption and various kinds of host kernel crashes. This fixes the problem by using register r31, which contains the vcpu pointer, instead of r3 and r4. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-13 17:02:48 +08:00
stw r6,VCPU_VRSAVE(r31)
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
mtlr r30
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
blr
/*
* Load up FP, VMX and VSX registers
* r4 = vcpu pointer
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
* N.B. r30 and r31 are volatile across this function,
* thus it is not callable from C.
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
*/
kvmppc_load_fp:
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
mflr r30
mr r31,r4
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
mfmsr r9
ori r8,r9,MSR_FP
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
oris r8,r8,MSR_VEC@h
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
#ifdef CONFIG_VSX
BEGIN_FTR_SECTION
oris r8,r8,MSR_VSX@h
END_FTR_SECTION_IFSET(CPU_FTR_VSX)
#endif
mtmsrd r8
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
addi r3,r4,VCPU_FPRS
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl load_fp_state
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
addi r3,r31,VCPU_VRS
KVM: PPC: Book3S HV: Fix ABIv2 on LE For code that doesn't live in modules we can just branch to the real function names, giving us compatibility with ABIv1 and ABIv2. Do this for the compiled-in code of HV KVM. Signed-off-by: Alexander Graf <agraf@suse.de>
2014-06-16 20:41:15 +08:00
bl load_vr_state
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
KVM: PPC: Book3S HV: Fix register usage when loading/saving VRSAVE Commit 595e4f7e697e ("KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit") changed the register usage in kvmppc_save_fp() and kvmppc_load_fp() but omitted changing the instructions that load and save VRSAVE. The result is that the VRSAVE value was loaded from a constant address, and saved to a location past the end of the vcpu struct, causing host kernel memory corruption and various kinds of host kernel crashes. This fixes the problem by using register r31, which contains the vcpu pointer, instead of r3 and r4. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-03-13 17:02:48 +08:00
lwz r7,VCPU_VRSAVE(r31)
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
mtspr SPRN_VRSAVE,r7
KVM: PPC: Book3S HV: Use load/store_fp_state functions in HV guest entry/exit This modifies kvmppc_load_fp and kvmppc_save_fp to use the generic FP/VSX and VMX load/store functions instead of open-coding the FP/VSX/VMX load/store instructions. Since kvmppc_load/save_fp don't follow C calling conventions, we make them private symbols within book3s_hv_rmhandlers.S. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-15 17:43:04 +08:00
mtlr r30
mr r4,r31
KVM: PPC: Add support for Book3S processors in hypervisor mode This adds support for KVM running on 64-bit Book 3S processors, specifically POWER7, in hypervisor mode. Using hypervisor mode means that the guest can use the processor's supervisor mode. That means that the guest can execute privileged instructions and access privileged registers itself without trapping to the host. This gives excellent performance, but does mean that KVM cannot emulate a processor architecture other than the one that the hardware implements. This code assumes that the guest is running paravirtualized using the PAPR (Power Architecture Platform Requirements) interface, which is the interface that IBM's PowerVM hypervisor uses. That means that existing Linux distributions that run on IBM pSeries machines will also run under KVM without modification. In order to communicate the PAPR hypercalls to qemu, this adds a new KVM_EXIT_PAPR_HCALL exit code to include/linux/kvm.h. Currently the choice between book3s_hv support and book3s_pr support (i.e. the existing code, which runs the guest in user mode) has to be made at kernel configuration time, so a given kernel binary can only do one or the other. This new book3s_hv code doesn't support MMIO emulation at present. Since we are running paravirtualized guests, this isn't a serious restriction. With the guest running in supervisor mode, most exceptions go straight to the guest. We will never get data or instruction storage or segment interrupts, alignment interrupts, decrementer interrupts, program interrupts, single-step interrupts, etc., coming to the hypervisor from the guest. Therefore this introduces a new KVMTEST_NONHV macro for the exception entry path so that we don't have to do the KVM test on entry to those exception handlers. We do however get hypervisor decrementer, hypervisor data storage, hypervisor instruction storage, and hypervisor emulation assist interrupts, so we have to handle those. In hypervisor mode, real-mode accesses can access all of RAM, not just a limited amount. Therefore we put all the guest state in the vcpu.arch and use the shadow_vcpu in the PACA only for temporary scratch space. We allocate the vcpu with kzalloc rather than vzalloc, and we don't use anything in the kvmppc_vcpu_book3s struct, so we don't allocate it. We don't have a shared page with the guest, but we still need a kvm_vcpu_arch_shared struct to store the values of various registers, so we include one in the vcpu_arch struct. The POWER7 processor has a restriction that all threads in a core have to be in the same partition. MMU-on kernel code counts as a partition (partition 0), so we have to do a partition switch on every entry to and exit from the guest. At present we require the host and guest to run in single-thread mode because of this hardware restriction. This code allocates a hashed page table for the guest and initializes it with HPTEs for the guest's Virtual Real Memory Area (VRMA). We require that the guest memory is allocated using 16MB huge pages, in order to simplify the low-level memory management. This also means that we can get away without tracking paging activity in the host for now, since huge pages can't be paged or swapped. This also adds a few new exports needed by the book3s_hv code. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2011-06-29 08:21:34 +08:00
blr
KVM: PPC: Book3S HV: Better handling of exceptions that happen in real mode When an interrupt or exception happens in the guest that comes to the host, the CPU goes to hypervisor real mode (MMU off) to handle the exception but doesn't change the MMU context. After saving a few registers, we then clear the "in guest" flag. If, for any reason, we get an exception in the real-mode code, that then gets handled by the normal kernel exception handlers, which turn the MMU on. This is disastrous if the MMU is still set to the guest context, since we end up executing instructions from random places in the guest kernel with hypervisor privilege. In order to catch this situation, we define a new value for the "in guest" flag, KVM_GUEST_MODE_HOST_HV, to indicate that we are in hypervisor real mode with guest MMU context. If the "in guest" flag is set to this value, we branch off to an emergency handler. For the moment, this just does a branch to self to stop the CPU from doing anything further. While we're here, we define another new flag value to indicate that we are in a HV guest, as distinct from a PR guest. This will be useful when we have a kernel that can support both PR and HV guests concurrently. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2013-10-04 19:45:04 +08:00
/*
* We come here if we get any exception or interrupt while we are
* executing host real mode code while in guest MMU context.
* For now just spin, but we should do something better.
*/
kvmppc_bad_host_intr:
b .
KVM: PPC: Book3S HV: Add transactional memory support This adds saving of the transactional memory (TM) checkpointed state on guest entry and exit. We only do this if we see that the guest has an active transaction. It also adds emulation of the TM state changes when delivering IRQs into the guest. According to the architecture, if we are transactional when an IRQ occurs, the TM state is changed to suspended, otherwise it's left unchanged. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Scott Wood <scottwood@freescale.com>
2014-03-25 07:47:02 +08:00
/*
* This mimics the MSR transition on IRQ delivery. The new guest MSR is taken
* from VCPU_INTR_MSR and is modified based on the required TM state changes.
* r11 has the guest MSR value (in/out)
* r9 has a vcpu pointer (in)
* r0 is used as a scratch register
*/
kvmppc_msr_interrupt:
rldicl r0, r11, 64 - MSR_TS_S_LG, 62
cmpwi r0, 2 /* Check if we are in transactional state.. */
ld r11, VCPU_INTR_MSR(r9)
bne 1f
/* ... if transactional, change to suspended */
li r0, 1
1: rldimi r11, r0, MSR_TS_S_LG, 63 - MSR_TS_T_LG
blr
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs This adds workarounds for two hardware bugs in the POWER8 performance monitor unit (PMU), both related to interrupt generation. The effect of these bugs is that PMU interrupts can get lost, leading to tools such as perf reporting fewer counts and samples than they should. The first bug relates to the PMAO (perf. mon. alert occurred) bit in MMCR0; setting it should cause an interrupt, but doesn't. The other bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0. Setting PMAE when a counter is negative and counter negative conditions are enabled to cause alerts should cause an alert, but doesn't. The workaround for the first bug is to create conditions where a counter will overflow, whenever we are about to restore a MMCR0 value that has PMAO set (and PMAO_SYNC clear). The workaround for the second bug is to freeze all counters using MMCR2 before reading MMCR0. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2014-05-26 17:48:40 +08:00
/*
* This works around a hardware bug on POWER8E processors, where
* writing a 1 to the MMCR0[PMAO] bit doesn't generate a
* performance monitor interrupt. Instead, when we need to have
* an interrupt pending, we have to arrange for a counter to overflow.
*/
kvmppc_fix_pmao:
li r3, 0
mtspr SPRN_MMCR2, r3
lis r3, (MMCR0_PMXE | MMCR0_FCECE)@h
ori r3, r3, MMCR0_PMCjCE | MMCR0_C56RUN
mtspr SPRN_MMCR0, r3
lis r3, 0x7fff
ori r3, r3, 0xffff
mtspr SPRN_PMC6, r3
isync
blr
KVM: PPC: Book3S HV: Accumulate timing information for real-mode code This reads the timebase at various points in the real-mode guest entry/exit code and uses that to accumulate total, minimum and maximum time spent in those parts of the code. Currently these times are accumulated per vcpu in 5 parts of the code: * rm_entry - time taken from the start of kvmppc_hv_entry() until just before entering the guest. * rm_intr - time from when we take a hypervisor interrupt in the guest until we either re-enter the guest or decide to exit to the host. This includes time spent handling hcalls in real mode. * rm_exit - time from when we decide to exit the guest until the return from kvmppc_hv_entry(). * guest - time spend in the guest * cede - time spent napping in real mode due to an H_CEDE hcall while other threads in the same vcore are active. These times are exposed in debugfs in a directory per vcpu that contains a file called "timings". This file contains one line for each of the 5 timings above, with the name followed by a colon and 4 numbers, which are the count (number of times the code has been executed), the total time, the minimum time, and the maximum time, all in nanoseconds. The overhead of the extra code amounts to about 30ns for an hcall that is handled in real mode (e.g. H_SET_DABR), which is about 25%. Since production environments may not wish to incur this overhead, the new code is conditional on a new config symbol, CONFIG_KVM_BOOK3S_HV_EXIT_TIMING. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-28 11:21:02 +08:00
#ifdef CONFIG_KVM_BOOK3S_HV_EXIT_TIMING
/*
* Start timing an activity
* r3 = pointer to time accumulation struct, r4 = vcpu
*/
kvmhv_start_timing:
ld r5, HSTATE_KVM_VCORE(r13)
lbz r6, VCORE_IN_GUEST(r5)
cmpwi r6, 0
beq 5f /* if in guest, need to */
ld r6, VCORE_TB_OFFSET(r5) /* subtract timebase offset */
5: mftb r5
subf r5, r6, r5
std r3, VCPU_CUR_ACTIVITY(r4)
std r5, VCPU_ACTIVITY_START(r4)
blr
/*
* Accumulate time to one activity and start another.
* r3 = pointer to new time accumulation struct, r4 = vcpu
*/
kvmhv_accumulate_time:
ld r5, HSTATE_KVM_VCORE(r13)
lbz r8, VCORE_IN_GUEST(r5)
cmpwi r8, 0
beq 4f /* if in guest, need to */
ld r8, VCORE_TB_OFFSET(r5) /* subtract timebase offset */
4: ld r5, VCPU_CUR_ACTIVITY(r4)
ld r6, VCPU_ACTIVITY_START(r4)
std r3, VCPU_CUR_ACTIVITY(r4)
mftb r7
subf r7, r8, r7
std r7, VCPU_ACTIVITY_START(r4)
cmpdi r5, 0
beqlr
subf r3, r6, r7
ld r8, TAS_SEQCOUNT(r5)
cmpdi r8, 0
addi r8, r8, 1
std r8, TAS_SEQCOUNT(r5)
lwsync
ld r7, TAS_TOTAL(r5)
add r7, r7, r3
std r7, TAS_TOTAL(r5)
ld r6, TAS_MIN(r5)
ld r7, TAS_MAX(r5)
beq 3f
cmpd r3, r6
bge 1f
3: std r3, TAS_MIN(r5)
1: cmpd r3, r7
ble 2f
std r3, TAS_MAX(r5)
2: lwsync
addi r8, r8, 1
std r8, TAS_SEQCOUNT(r5)
blr
#endif
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