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e0b7ec058c
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>
179 lines
4.7 KiB
ArmAsm
179 lines
4.7 KiB
ArmAsm
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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*
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* Derived from book3s_interrupts.S, which is:
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* Copyright SUSE Linux Products GmbH 2009
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*
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* Authors: Alexander Graf <agraf@suse.de>
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*/
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#include <asm/ppc_asm.h>
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#include <asm/kvm_asm.h>
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#include <asm/reg.h>
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#include <asm/page.h>
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#include <asm/asm-offsets.h>
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#include <asm/exception-64s.h>
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#include <asm/ppc-opcode.h>
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/*****************************************************************************
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* *
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* Guest entry / exit code that is in kernel module memory (vmalloc) *
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* *
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****************************************************************************/
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/* Registers:
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* none
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*/
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_GLOBAL(__kvmppc_vcore_entry)
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/* Write correct stack frame */
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mflr r0
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std r0,PPC_LR_STKOFF(r1)
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/* Save host state to the stack */
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stdu r1, -SWITCH_FRAME_SIZE(r1)
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/* Save non-volatile registers (r14 - r31) and CR */
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SAVE_NVGPRS(r1)
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mfcr r3
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std r3, _CCR(r1)
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/* Save host DSCR */
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BEGIN_FTR_SECTION
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mfspr r3, SPRN_DSCR
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std r3, HSTATE_DSCR(r13)
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END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
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BEGIN_FTR_SECTION
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/* Save host DABR */
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mfspr r3, SPRN_DABR
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std r3, HSTATE_DABR(r13)
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END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
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/* Hard-disable interrupts */
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mfmsr r10
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std r10, HSTATE_HOST_MSR(r13)
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rldicl r10,r10,48,1
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rotldi r10,r10,16
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mtmsrd r10,1
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/* Save host PMU registers */
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li r3, 1
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sldi r3, r3, 31 /* MMCR0_FC (freeze counters) bit */
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mfspr r7, SPRN_MMCR0 /* save MMCR0 */
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mtspr SPRN_MMCR0, r3 /* freeze all counters, disable interrupts */
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mfspr r6, SPRN_MMCRA
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BEGIN_FTR_SECTION
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/* On P7, clear MMCRA in order to disable SDAR updates */
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li r5, 0
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mtspr SPRN_MMCRA, r5
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END_FTR_SECTION_IFSET(CPU_FTR_ARCH_206)
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isync
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ld r3, PACALPPACAPTR(r13) /* is the host using the PMU? */
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lbz r5, LPPACA_PMCINUSE(r3)
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cmpwi r5, 0
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beq 31f /* skip if not */
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mfspr r5, SPRN_MMCR1
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std r7, HSTATE_MMCR(r13)
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std r5, HSTATE_MMCR + 8(r13)
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std r6, HSTATE_MMCR + 16(r13)
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mfspr r3, SPRN_PMC1
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mfspr r5, SPRN_PMC2
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mfspr r6, SPRN_PMC3
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mfspr r7, SPRN_PMC4
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mfspr r8, SPRN_PMC5
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mfspr r9, SPRN_PMC6
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BEGIN_FTR_SECTION
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mfspr r10, SPRN_PMC7
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mfspr r11, SPRN_PMC8
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END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
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stw r3, HSTATE_PMC(r13)
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stw r5, HSTATE_PMC + 4(r13)
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stw r6, HSTATE_PMC + 8(r13)
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stw r7, HSTATE_PMC + 12(r13)
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stw r8, HSTATE_PMC + 16(r13)
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stw r9, HSTATE_PMC + 20(r13)
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BEGIN_FTR_SECTION
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stw r10, HSTATE_PMC + 24(r13)
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stw r11, HSTATE_PMC + 28(r13)
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END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
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31:
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/*
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* Put whatever is in the decrementer into the
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* hypervisor decrementer.
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*/
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mfspr r8,SPRN_DEC
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mftb r7
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mtspr SPRN_HDEC,r8
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extsw r8,r8
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add r8,r8,r7
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std r8,HSTATE_DECEXP(r13)
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#ifdef CONFIG_SMP
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/*
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* On PPC970, if the guest vcpu has an external interrupt pending,
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* send ourselves an IPI so as to interrupt the guest once it
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* enables interrupts. (It must have interrupts disabled,
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* otherwise we would already have delivered the interrupt.)
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*
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* XXX If this is a UP build, smp_send_reschedule is not available,
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* so the interrupt will be delayed until the next time the vcpu
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* enters the guest with interrupts enabled.
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*/
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BEGIN_FTR_SECTION
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ld r4, HSTATE_KVM_VCPU(r13)
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ld r0, VCPU_PENDING_EXC(r4)
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li r7, (1 << BOOK3S_IRQPRIO_EXTERNAL)
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oris r7, r7, (1 << BOOK3S_IRQPRIO_EXTERNAL_LEVEL)@h
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and. r0, r0, r7
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beq 32f
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lhz r3, PACAPACAINDEX(r13)
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bl smp_send_reschedule
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nop
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32:
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END_FTR_SECTION_IFSET(CPU_FTR_ARCH_201)
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#endif /* CONFIG_SMP */
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/* Jump to partition switch code */
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bl .kvmppc_hv_entry_trampoline
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nop
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/*
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* We return here in virtual mode after the guest exits
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* with something that we can't handle in real mode.
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* Interrupts are enabled again at this point.
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*/
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/*
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* Register usage at this point:
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*
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* R1 = host R1
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* R2 = host R2
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* R12 = exit handler id
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* R13 = PACA
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*/
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/* Restore non-volatile host registers (r14 - r31) and CR */
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REST_NVGPRS(r1)
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ld r4, _CCR(r1)
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mtcr r4
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addi r1, r1, SWITCH_FRAME_SIZE
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ld r0, PPC_LR_STKOFF(r1)
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mtlr r0
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blr
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