kvm_unmap_hva is long gone, and we only have kvm_unmap_hva_range to
deal with. Drop the now obsolete code.
Fixes: fb1522e099 ("KVM: update to new mmu_notifier semantic v2")
Cc: James Hogan <jhogan@kernel.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Commit a6f177efaa ("KVM: Reenter guest after emulation failure if
due to access to non-mmio address") added reexecute_instruction() to
handle the scenario where two (or more) vCPUS race to write a shadowed
page, i.e. reexecute_instruction() is intended to return true if and
only if the instruction being emulated was accessing a shadowed page.
As L0 is only explicitly shadowing L1 tables, an emulation failure of
a nested VM instruction cannot be due to a race to write a shadowed
page and so should never be re-executed.
This fixes an issue where an "MMIO" emulation failure[1] in L2 is all
but guaranteed to result in an infinite loop when TDP is enabled.
Because "cr2" is actually an L2 GPA when TDP is enabled, calling
kvm_mmu_gva_to_gpa_write() to translate cr2 in the non-direct mapped
case (L2 is never direct mapped) will almost always yield UNMAPPED_GVA
and cause reexecute_instruction() to immediately return true. The
!mmio_info_in_cache() check in kvm_mmu_page_fault() doesn't catch this
case because mmio_info_in_cache() returns false for a nested MMU (the
MMIO caching currently handles L1 only, e.g. to cache nested guests'
GPAs we'd have to manually flush the cache when switching between
VMs and when L1 updated its page tables controlling the nested guest).
Way back when, commit 68be080345 ("KVM: x86: never re-execute
instruction with enabled tdp") changed reexecute_instruction() to
always return false when using TDP under the assumption that KVM would
only get into the emulator for MMIO. Commit 95b3cf69bd ("KVM: x86:
let reexecute_instruction work for tdp") effectively reverted that
behavior in order to handle the scenario where emulation failed due to
an access from L1 to the shadow page tables for L2, but it didn't
account for the case where emulation failed in L2 with TDP enabled.
All of the above logic also applies to retry_instruction(), added by
commit 1cb3f3ae5a ("KVM: x86: retry non-page-table writing
instructions"). An indefinite loop in retry_instruction() should be
impossible as it protects against retrying the same instruction over
and over, but it's still correct to not retry an L2 instruction in
the first place.
Fix the immediate issue by adding a check for a nested guest when
determining whether or not to allow retry in kvm_mmu_page_fault().
In addition to fixing the immediate bug, add WARN_ON_ONCE in the
retry functions since they are not designed to handle nested cases,
i.e. they need to be modified even if there is some scenario in the
future where we want to allow retrying a nested guest.
[1] This issue was encountered after commit 3a2936dedd ("kvm: mmu:
Don't expose private memslots to L2") changed the page fault path
to return KVM_PFN_NOSLOT when translating an L2 access to a
prive memslot. Returning KVM_PFN_NOSLOT is semantically correct
when we want to hide a memslot from L2, i.e. there effectively is
no defined memory region for L2, but it has the unfortunate side
effect of making KVM think the GFN is a MMIO page, thus triggering
emulation. The failure occurred with in-development code that
deliberately exposed a private memslot to L2, which L2 accessed
with an instruction that is not emulated by KVM.
Fixes: 95b3cf69bd ("KVM: x86: let reexecute_instruction work for tdp")
Fixes: 1cb3f3ae5a ("KVM: x86: retry non-page-table writing instructions")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Cc: Xiao Guangrong <xiaoguangrong@tencent.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Effectively force kvm_mmu_page_fault() to opt-in to allowing retry to
make it more obvious when and why it allows emulation to be retried.
Previously this approach was less convenient due to retry and
re-execute behavior being controlled by separate flags that were also
inverted in their implementations (opt-in versus opt-out).
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
retry_instruction() and reexecute_instruction() are a package deal,
i.e. there is no scenario where one is allowed and the other is not.
Merge their controlling emulation type flags to enforce this in code.
Name the combined flag EMULTYPE_ALLOW_RETRY to make it abundantly
clear that we are allowing re{try,execute} to occur, as opposed to
explicitly requesting retry of a previously failed instruction.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Re-execution of an instruction after emulation decode failure is
intended to be used only when emulating shadow page accesses. Invert
the flag to make allowing re-execution opt-in since that behavior is
by far in the minority.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
For x86 this brings in PCID emulation and CR3 caching for shadow page
tables, nested VMX live migration, nested VMCS shadowing, an optimized
IPI hypercall, and some optimizations.
ARM will come next week.
There is a semantic conflict because tip also added an .init_platform
callback to kvm.c. Please keep the initializer from this branch,
and add a call to kvmclock_init (added by tip) inside kvm_init_platform
(added here).
Also, there is a backmerge from 4.18-rc6. This is because of a
refactoring that conflicted with a relatively late bugfix and
resulted in a particularly hellish conflict. Because the conflict
was only due to unfortunate timing of the bugfix, I backmerged and
rebased the refactoring rather than force the resolution on you.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull first set of KVM updates from Paolo Bonzini:
"PPC:
- minor code cleanups
x86:
- PCID emulation and CR3 caching for shadow page tables
- nested VMX live migration
- nested VMCS shadowing
- optimized IPI hypercall
- some optimizations
ARM will come next week"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (85 commits)
kvm: x86: Set highest physical address bits in non-present/reserved SPTEs
KVM/x86: Use CC_SET()/CC_OUT in arch/x86/kvm/vmx.c
KVM: X86: Implement PV IPIs in linux guest
KVM: X86: Add kvm hypervisor init time platform setup callback
KVM: X86: Implement "send IPI" hypercall
KVM/x86: Move X86_CR4_OSXSAVE check into kvm_valid_sregs()
KVM: x86: Skip pae_root shadow allocation if tdp enabled
KVM/MMU: Combine flushing remote tlb in mmu_set_spte()
KVM: vmx: skip VMWRITE of HOST_{FS,GS}_BASE when possible
KVM: vmx: skip VMWRITE of HOST_{FS,GS}_SEL when possible
KVM: vmx: always initialize HOST_{FS,GS}_BASE to zero during setup
KVM: vmx: move struct host_state usage to struct loaded_vmcs
KVM: vmx: compute need to reload FS/GS/LDT on demand
KVM: nVMX: remove a misleading comment regarding vmcs02 fields
KVM: vmx: rename __vmx_load_host_state() and vmx_save_host_state()
KVM: vmx: add dedicated utility to access guest's kernel_gs_base
KVM: vmx: track host_state.loaded using a loaded_vmcs pointer
KVM: vmx: refactor segmentation code in vmx_save_host_state()
kvm: nVMX: Fix fault priority for VMX operations
kvm: nVMX: Fix fault vector for VMX operation at CPL > 0
...
Always set the 5 upper-most supported physical address bits to 1 for SPTEs
that are marked as non-present or reserved, to make them unusable for
L1TF attacks from the guest. Currently, this just applies to MMIO SPTEs.
(We do not need to mark PTEs that are completely 0 as physical page 0
is already reserved.)
This allows mitigation of L1TF without disabling hyper-threading by using
shadow paging mode instead of EPT.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Considering the fact that the pae_root shadow is not needed when
tdp is in use, skip the pae_root shadow page allocation to allow
mmu creation even not being able to obtain memory from DMA32
zone when particular cgroup cpuset.mems or mempolicy control is
applied.
Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
mmu_set_spte() flushes remote tlbs for drop_parent_pte/drop_spte()
and set_spte() separately. This may introduce redundant flush. This
patch is to combine these flushes and check flush request after
calling set_spte().
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Reviewed-by: Junaid Shahid <junaids@google.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Merge check of "sp->role.cr4_pae != !!is_pae(vcpu))" and "vcpu->
arch.mmu.sync_page(vcpu, sp) == 0". kvm_mmu_prepare_zap_page()
is called under both these conditions.
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Adds support for storing multiple previous CR3/root_hpa pairs maintained
as an LRU cache, so that the lockless CR3 switch path can be used when
switching back to any of them.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This needs a minor bug fix. The updated patch is as follows.
Thanks,
Junaid
------------------------------------------------------------------------------
kvm_mmu_invlpg() and kvm_mmu_invpcid_gva() only need to flush the TLB
entries for the specific guest virtual address, instead of flushing all
TLB entries associated with the VM.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When the guest indicates that the TLB doesn't need to be flushed in a
CR3 switch, we can also skip resyncing the shadow page tables since an
out-of-sync shadow page table is equivalent to an out-of-sync TLB.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_mmu_free_roots() now takes a mask specifying which roots to free, so
that either one of the roots (active/previous) can be individually freed
when needed.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This allows invlpg() to be called using either the active root_hpa
or the prev_root_hpa.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When PCIDs are enabled, the MSb of the source operand for a MOV-to-CR3
instruction indicates that the TLB doesn't need to be flushed.
This change enables this optimization for MOV-to-CR3s in the guest
that have been intercepted by KVM for shadow paging and are handled
within the fast CR3 switch path.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Implement support for INVPCID in shadow paging mode as well.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove the implicit flush from the set_cr3 handlers, so that the
callers are able to decide whether to flush the TLB or not.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use the fast CR3 switch mechanism to locklessly change the MMU root
page when switching between L1 and L2. The switch from L2 to L1 should
always go through the fast path, while the switch from L1 to L2 should
go through the fast path if L1's CR3/EPTP for L2 hasn't changed
since the last time.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This adds support for re-initializing the MMU context in a different
mode while preserving the active root_hpa and the prev_root.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This generalizes the lockless CR3 switch path to be able to work
across different MMU modes (e.g. nested vs non-nested) by checking
that the expected page role of the new root page matches the page role
of the previously stored root page in addition to checking that the new
CR3 matches the previous CR3. Furthermore, instead of loading the
hardware CR3 in fast_cr3_switch(), it is now done in vcpu_enter_guest(),
as by that time the MMU context would be up-to-date with the VCPU mode.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The KVM_REQ_LOAD_CR3 request loads the hardware CR3 using the
current root_hpa.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
These functions factor out the base role calculation from the
corresponding kvm_init_*_mmu() functions. The new functions return
what would be the role assigned to a root page in the current VCPU
state. This can be masked with mmu_base_role_mask to derive the base
role.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When using shadow paging, a CR3 switch in the guest results in a VM Exit.
In the common case, that VM exit doesn't require much processing by KVM.
However, it does acquire the MMU lock, which can start showing signs of
contention under some workloads even on a 2 VCPU VM when the guest is
using KPTI. Therefore, we add a fast path that avoids acquiring the MMU
lock in the most common cases e.g. when switching back and forth between
the kernel and user mode CR3s used by KPTI with no guest page table
changes in between.
For now, this fast path is implemented only for 64-bit guests and hosts
to avoid the handling of PDPTEs, but it can be extended later to 32-bit
guests and/or hosts as well.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_mmu_sync_roots() can locklessly check whether a sync is needed and just
bail out if it isn't.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
sync_page() calls set_spte() from a loop across a page table. It would
work better if set_spte() left the TLB flushing to its callers, so that
sync_page() can aggregate into a single call.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The size of kvm's shadow page tables corresponds to the size of the
guest virtual machines on the system. Large VMs can spend a significant
amount of memory as shadow page tables which can not be left as system
memory overhead. So, account shadow page tables to the kmemcg.
[shakeelb@google.com: replace (GFP_KERNEL|__GFP_ACCOUNT) with GFP_KERNEL_ACCOUNT]
Link: http://lkml.kernel.org/r/20180629140224.205849-1-shakeelb@google.com
Link: http://lkml.kernel.org/r/20180627181349.149778-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add the logic for flushing L1D on VMENTER. The flush depends on the static
key being enabled and the new l1tf_flush_l1d flag being set.
The flags is set:
- Always, if the flush module parameter is 'always'
- Conditionally at:
- Entry to vcpu_run(), i.e. after executing user space
- From the sched_in notifier, i.e. when switching to a vCPU thread.
- From vmexit handlers which are considered unsafe, i.e. where
sensitive data can be brought into L1D:
- The emulator, which could be a good target for other speculative
execution-based threats,
- The MMU, which can bring host page tables in the L1 cache.
- External interrupts
- Nested operations that require the MMU (see above). That is
vmptrld, vmptrst, vmclear,vmwrite,vmread.
- When handling invept,invvpid
[ tglx: Split out from combo patch and reduced to a single flag ]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* ARM: lazy context-switching of FPSIMD registers on arm64, "split"
regions for vGIC redistributor
* s390: cleanups for nested, clock handling, crypto, storage keys and
control register bits
* x86: many bugfixes, implement more Hyper-V super powers,
implement lapic_timer_advance_ns even when the LAPIC timer
is emulated using the processor's VMX preemption timer. Two
security-related bugfixes at the top of the branch.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"Small update for KVM:
ARM:
- lazy context-switching of FPSIMD registers on arm64
- "split" regions for vGIC redistributor
s390:
- cleanups for nested
- clock handling
- crypto
- storage keys
- control register bits
x86:
- many bugfixes
- implement more Hyper-V super powers
- implement lapic_timer_advance_ns even when the LAPIC timer is
emulated using the processor's VMX preemption timer.
- two security-related bugfixes at the top of the branch"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (79 commits)
kvm: fix typo in flag name
kvm: x86: use correct privilege level for sgdt/sidt/fxsave/fxrstor access
KVM: x86: pass kvm_vcpu to kvm_read_guest_virt and kvm_write_guest_virt_system
KVM: x86: introduce linear_{read,write}_system
kvm: nVMX: Enforce cpl=0 for VMX instructions
kvm: nVMX: Add support for "VMWRITE to any supported field"
kvm: nVMX: Restrict VMX capability MSR changes
KVM: VMX: Optimize tscdeadline timer latency
KVM: docs: nVMX: Remove known limitations as they do not exist now
KVM: docs: mmu: KVM support exposing SLAT to guests
kvm: no need to check return value of debugfs_create functions
kvm: Make VM ioctl do valloc for some archs
kvm: Change return type to vm_fault_t
KVM: docs: mmu: Fix link to NPT presentation from KVM Forum 2008
kvm: x86: Amend the KVM_GET_SUPPORTED_CPUID API documentation
KVM: x86: hyperv: declare KVM_CAP_HYPERV_TLBFLUSH capability
KVM: x86: hyperv: simplistic HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}_EX implementation
KVM: x86: hyperv: simplistic HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE} implementation
KVM: introduce kvm_make_vcpus_request_mask() API
KVM: x86: hyperv: do rep check for each hypercall separately
...
handle_mmio_page_fault() was recently moved to be an internal-only
MMU function, i.e. it's static and no longer defined in kvm_host.h.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
These private pages have special purposes in the virtualization of L1,
but not in the virtualization of L2. In particular, L1's APIC access
page should never be entered into L2's page tables, because this
causes a great deal of confusion when the APIC virtualization hardware
is being used to accelerate L2's accesses to its own APIC.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
L1 and L2 need to have disjoint mappings, so that L1's APIC access
page (under VMX) can be omitted from L2's mappings.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Extract the logic to free a root page in a separate function to avoid code
duplication in mmu_free_roots(). Also, change it to an exported function
i.e. kvm_mmu_free_roots().
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.
Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.
The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.
In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.
Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
- VHE optimizations
- EL2 address space randomization
- speculative execution mitigations ("variant 3a", aka execution past invalid
privilege register access)
- bugfixes and cleanups
PPC:
- improvements for the radix page fault handler for HV KVM on POWER9
s390:
- more kvm stat counters
- virtio gpu plumbing
- documentation
- facilities improvements
x86:
- support for VMware magic I/O port and pseudo-PMCs
- AMD pause loop exiting
- support for AMD core performance extensions
- support for synchronous register access
- expose nVMX capabilities to userspace
- support for Hyper-V signaling via eventfd
- use Enlightened VMCS when running on Hyper-V
- allow userspace to disable MWAIT/HLT/PAUSE vmexits
- usual roundup of optimizations and nested virtualization bugfixes
Generic:
- API selftest infrastructure (though the only tests are for x86 as of now)
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"ARM:
- VHE optimizations
- EL2 address space randomization
- speculative execution mitigations ("variant 3a", aka execution past
invalid privilege register access)
- bugfixes and cleanups
PPC:
- improvements for the radix page fault handler for HV KVM on POWER9
s390:
- more kvm stat counters
- virtio gpu plumbing
- documentation
- facilities improvements
x86:
- support for VMware magic I/O port and pseudo-PMCs
- AMD pause loop exiting
- support for AMD core performance extensions
- support for synchronous register access
- expose nVMX capabilities to userspace
- support for Hyper-V signaling via eventfd
- use Enlightened VMCS when running on Hyper-V
- allow userspace to disable MWAIT/HLT/PAUSE vmexits
- usual roundup of optimizations and nested virtualization bugfixes
Generic:
- API selftest infrastructure (though the only tests are for x86 as
of now)"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (174 commits)
kvm: x86: fix a prototype warning
kvm: selftests: add sync_regs_test
kvm: selftests: add API testing infrastructure
kvm: x86: fix a compile warning
KVM: X86: Add Force Emulation Prefix for "emulate the next instruction"
KVM: X86: Introduce handle_ud()
KVM: vmx: unify adjacent #ifdefs
x86: kvm: hide the unused 'cpu' variable
KVM: VMX: remove bogus WARN_ON in handle_ept_misconfig
Revert "KVM: X86: Fix SMRAM accessing even if VM is shutdown"
kvm: Add emulation for movups/movupd
KVM: VMX: raise internal error for exception during invalid protected mode state
KVM: nVMX: Optimization: Dont set KVM_REQ_EVENT when VMExit with nested_run_pending
KVM: nVMX: Require immediate-exit when event reinjected to L2 and L1 event pending
KVM: x86: Fix misleading comments on handling pending exceptions
KVM: x86: Rename interrupt.pending to interrupt.injected
KVM: VMX: No need to clear pending NMI/interrupt on inject realmode interrupt
x86/kvm: use Enlightened VMCS when running on Hyper-V
x86/hyper-v: detect nested features
x86/hyper-v: define struct hv_enlightened_vmcs and clean field bits
...
The bug that led to commit 95e057e258
was a benign warning (no adverse affects other than the warning
itself) that was detected by syzkaller. Further inspection shows
that the WARN_ON in question, in handle_ept_misconfig(), is
unnecessary and flawed (this was also briefly discussed in the
original patch: https://patchwork.kernel.org/patch/10204649).
* The WARN_ON is unnecessary as kvm_mmu_page_fault() will WARN
if reserved bits are set in the SPTEs, i.e. it covers the case
where an EPT misconfig occurred because of a KVM bug.
* The WARN_ON is flawed because it will fire on any system error
code that is hit while handling the fault, e.g. -ENOMEM can be
returned by mmu_topup_memory_caches() while handling a legitmate
MMIO EPT misconfig.
The original behavior of returning -EFAULT when userspace munmaps
an HVA without first removing the memslot is correct and desirable,
i.e. KVM is letting userspace know it has generated a bad address.
Returning RET_PF_EMULATE masks the WARN_ON in the EPT misconfig path,
but does not fix the underlying bug, i.e. the WARN_ON is bogus.
Furthermore, returning RET_PF_EMULATE has the unwanted side effect of
causing KVM to attempt to emulate an instruction on any page fault
with an invalid HVA translation, e.g. a not-present EPT violation
on a VM_PFNMAP VMA whose fault handler failed to insert a PFN.
* There is no guarantee that the fault is directly related to the
instruction, i.e. the fault could have been triggered by a side
effect memory access in the guest, e.g. while vectoring a #DB or
writing a tracing record. This could cause KVM to effectively
mask the fault if KVM doesn't model the behavior leading to the
fault, i.e. emulation could succeed and resume the guest.
* If emulation does fail, KVM will return EMULATION_FAILED instead
of -EFAULT, which is a red herring as the user will either debug
a bogus emulation attempt or scratch their head wondering why we
were attempting emulation in the first place.
TL;DR: revert to returning -EFAULT and remove the bogus WARN_ON in
handle_ept_misconfig in a future patch.
This reverts commit 95e057e258.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When using device passthrough with SME active, the MMIO range that is
mapped for the device should not be mapped encrypted. Add a check in
set_spte() to insure that a page is not mapped encrypted if that page
is a device MMIO page as indicated by kvm_is_mmio_pfn().
Cc: <stable@vger.kernel.org> # 4.14.x-
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
- optimization for the exitless interrupt support that was merged in 4.16-rc1
- improve the branch prediction blocking for nested KVM
- replace some jump tables with switch statements to improve expoline performance
- fixes for multiple epoch facility
ARM:
- fix the interaction of userspace irqchip VMs with in-kernel irqchip VMs
- make sure we can build 32-bit KVM/ARM with gcc-8.
x86:
- fixes for AMD SEV
- fixes for Intel nested VMX, emulated UMIP and a dump_stack() on VM startup
- fixes for async page fault migration
- small optimization to PV TLB flush (new in 4.16-rc1)
- syzkaller fixes
Generic:
- compiler warning fixes
- syzkaller fixes
- more improvements to the kvm_stat tool
Two more small Spectre fixes are going to reach you via Ingo.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini:
"s390:
- optimization for the exitless interrupt support that was merged in 4.16-rc1
- improve the branch prediction blocking for nested KVM
- replace some jump tables with switch statements to improve expoline performance
- fixes for multiple epoch facility
ARM:
- fix the interaction of userspace irqchip VMs with in-kernel irqchip VMs
- make sure we can build 32-bit KVM/ARM with gcc-8.
x86:
- fixes for AMD SEV
- fixes for Intel nested VMX, emulated UMIP and a dump_stack() on VM startup
- fixes for async page fault migration
- small optimization to PV TLB flush (new in 4.16-rc1)
- syzkaller fixes
Generic:
- compiler warning fixes
- syzkaller fixes
- more improvements to the kvm_stat tool
Two more small Spectre fixes are going to reach you via Ingo"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (40 commits)
KVM: SVM: Fix SEV LAUNCH_SECRET command
KVM: SVM: install RSM intercept
KVM: SVM: no need to call access_ok() in LAUNCH_MEASURE command
include: psp-sev: Capitalize invalid length enum
crypto: ccp: Fix sparse, use plain integer as NULL pointer
KVM: X86: Avoid traversing all the cpus for pv tlb flush when steal time is disabled
x86/kvm: Make parse_no_xxx __init for kvm
KVM: x86: fix backward migration with async_PF
kvm: fix warning for non-x86 builds
kvm: fix warning for CONFIG_HAVE_KVM_EVENTFD builds
tools/kvm_stat: print 'Total' line for multiple events only
tools/kvm_stat: group child events indented after parent
tools/kvm_stat: separate drilldown and fields filtering
tools/kvm_stat: eliminate extra guest/pid selection dialog
tools/kvm_stat: mark private methods as such
tools/kvm_stat: fix debugfs handling
tools/kvm_stat: print error on invalid regex
tools/kvm_stat: fix crash when filtering out all non-child trace events
tools/kvm_stat: avoid 'is' for equality checks
tools/kvm_stat: use a more pythonic way to iterate over dictionaries
...
Reported by syzkaller:
WARNING: CPU: 6 PID: 2434 at arch/x86/kvm/vmx.c:6660 handle_ept_misconfig+0x54/0x1e0 [kvm_intel]
CPU: 6 PID: 2434 Comm: repro_test Not tainted 4.15.0+ #4
RIP: 0010:handle_ept_misconfig+0x54/0x1e0 [kvm_intel]
Call Trace:
vmx_handle_exit+0xbd/0xe20 [kvm_intel]
kvm_arch_vcpu_ioctl_run+0xdaf/0x1d50 [kvm]
kvm_vcpu_ioctl+0x3e9/0x720 [kvm]
do_vfs_ioctl+0xa4/0x6a0
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x25/0x9c
The testcase creates a first thread to issue KVM_SMI ioctl, and then creates
a second thread to mmap and operate on the same vCPU. This triggers a race
condition when running the testcase with multiple threads. Sometimes one thread
exits with a triple fault while another thread mmaps and operates on the same
vCPU. Because CS=0x3000/IP=0x8000 is not mapped, accessing the SMI handler
results in an EPT misconfig. This patch fixes it by returning RET_PF_EMULATE
in kvm_handle_bad_page(), which will go on to cause an emulation failure and an
exit with KVM_EXIT_INTERNAL_ERROR.
Reported-by: syzbot+c1d9517cab094dae65e446c0c5b4de6c40f4dc58@syzkaller.appspotmail.com
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull x86 PTI and Spectre related fixes and updates from Ingo Molnar:
"Here's the latest set of Spectre and PTI related fixes and updates:
Spectre:
- Add entry code register clearing to reduce the Spectre attack
surface
- Update the Spectre microcode blacklist
- Inline the KVM Spectre helpers to get close to v4.14 performance
again.
- Fix indirect_branch_prediction_barrier()
- Fix/improve Spectre related kernel messages
- Fix array_index_nospec_mask() asm constraint
- KVM: fix two MSR handling bugs
PTI:
- Fix a paranoid entry PTI CR3 handling bug
- Fix comments
objtool:
- Fix paranoid_entry() frame pointer warning
- Annotate WARN()-related UD2 as reachable
- Various fixes
- Add Add Peter Zijlstra as objtool co-maintainer
Misc:
- Various x86 entry code self-test fixes
- Improve/simplify entry code stack frame generation and handling
after recent heavy-handed PTI and Spectre changes. (There's two
more WIP improvements expected here.)
- Type fix for cache entries
There's also some low risk non-fix changes I've included in this
branch to reduce backporting conflicts:
- rename a confusing x86_cpu field name
- de-obfuscate the naming of single-TLB flushing primitives"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
x86/entry/64: Fix CR3 restore in paranoid_exit()
x86/cpu: Change type of x86_cache_size variable to unsigned int
x86/spectre: Fix an error message
x86/cpu: Rename cpu_data.x86_mask to cpu_data.x86_stepping
selftests/x86/mpx: Fix incorrect bounds with old _sigfault
x86/mm: Rename flush_tlb_single() and flush_tlb_one() to __flush_tlb_one_[user|kernel]()
x86/speculation: Add <asm/msr-index.h> dependency
nospec: Move array_index_nospec() parameter checking into separate macro
x86/speculation: Fix up array_index_nospec_mask() asm constraint
x86/debug: Use UD2 for WARN()
x86/debug, objtool: Annotate WARN()-related UD2 as reachable
objtool: Fix segfault in ignore_unreachable_insn()
selftests/x86: Disable tests requiring 32-bit support on pure 64-bit systems
selftests/x86: Do not rely on "int $0x80" in single_step_syscall.c
selftests/x86: Do not rely on "int $0x80" in test_mremap_vdso.c
selftests/x86: Fix build bug caused by the 5lvl test which has been moved to the VM directory
selftests/x86/pkeys: Remove unused functions
selftests/x86: Clean up and document sscanf() usage
selftests/x86: Fix vDSO selftest segfault for vsyscall=none
x86/entry/64: Remove the unused 'icebp' macro
...
With retpoline, tight loops of "call this function for every XXX" are
very much pessimised by taking a prediction miss *every* time. This one
is by far the biggest contributor to the guest launch time with retpoline.
By marking the iterator slot_handle_…() functions always_inline, we can
ensure that the indirect function call can be optimised away into a
direct call and it actually generates slightly smaller code because
some of the other conditionals can get optimised away too.
Performance is now pretty close to what we see with nospectre_v2 on
the command line.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Filippo Sironi <sironi@amazon.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arjan.van.de.ven@intel.com
Cc: dave.hansen@intel.com
Cc: jmattson@google.com
Cc: karahmed@amazon.de
Cc: kvm@vger.kernel.org
Cc: rkrcmar@redhat.com
Link: http://lkml.kernel.org/r/1518305967-31356-4-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Some reserved pages, such as those from NVDIMM DAX devices, are not
for MMIO, and can be mapped with cached memory type for better
performance. However, the above check misconceives those pages as
MMIO. Because KVM maps MMIO pages with UC memory type, the
performance of guest accesses to those pages would be harmed.
Therefore, we check the host memory type in addition and only treat
UC/UC-/WC pages as MMIO.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Reported-by: Cuevas Escareno, Ivan D <ivan.d.cuevas.escareno@intel.com>
Reported-by: Kumar, Karthik <karthik.kumar@intel.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This part of Secure Encrypted Virtualization (SEV) patch series focuses on KVM
changes required to create and manage SEV guests.
SEV is an extension to the AMD-V architecture which supports running encrypted
virtual machine (VMs) under the control of a hypervisor. Encrypted VMs have their
pages (code and data) secured such that only the guest itself has access to
unencrypted version. Each encrypted VM is associated with a unique encryption key;
if its data is accessed to a different entity using a different key the encrypted
guest's data will be incorrectly decrypted, leading to unintelligible data.
This security model ensures that hypervisor will no longer able to inspect or
alter any guest code or data.
The key management of this feature is handled by a separate processor known as
the AMD Secure Processor (AMD-SP) which is present on AMD SOCs. The SEV Key
Management Specification (see below) provides a set of commands which can be
used by hypervisor to load virtual machine keys through the AMD-SP driver.
The patch series adds a new ioctl in KVM driver (KVM_MEMORY_ENCRYPT_OP). The
ioctl will be used by qemu to issue SEV guest-specific commands defined in Key
Management Specification.
The following links provide additional details:
AMD Memory Encryption white paper:
http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf
AMD64 Architecture Programmer's Manual:
http://support.amd.com/TechDocs/24593.pdf
SME is section 7.10
SEV is section 15.34
SEV Key Management:
http://support.amd.com/TechDocs/55766_SEV-KM API_Specification.pdf
KVM Forum Presentation:
http://www.linux-kvm.org/images/7/74/02x08A-Thomas_Lendacky-AMDs_Virtualizatoin_Memory_Encryption_Technology.pdf
SEV Guest BIOS support:
SEV support has been add to EDKII/OVMF BIOS
https://github.com/tianocore/edk2
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Patch "mm,vmscan: mark register_shrinker() as __must_check" is
queued for 4.16 in linux-mm and adds a warning about the unchecked
call to register_shrinker:
arch/x86/kvm/mmu.c:5485:2: warning: ignoring return value of 'register_shrinker', declared with attribute warn_unused_result [-Wunused-result]
This changes the kvm_mmu_module_init() function to fail itself
when the call to register_shrinker fails.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For example, when two APF's for page ready happen after one exit and
the first one becomes pending, the second one will result in #DF.
Instead, just handle the second page fault synchronously.
Reported-by: Ross Zwisler <zwisler@gmail.com>
Message-ID: <CAOxpaSUBf8QoOZQ1p4KfUp0jq76OKfGY4Uxs-Gg8ngReD99xww@mail.gmail.com>
Reported-by: Alec Blayne <ab@tevsa.net>
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The kvm_mmu_clear_all_pte_masks interface is only used by kvm_mmu_module_init
locally, and does not need to be called by other module, make it static.
This patch cleans up sparse warning:
symbol 'kvm_mmu_clear_all_pte_masks' was not declared. Should it be static?
Signed-off-by: Gimcuan Hui <gimcuan@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The below test case can cause infinite loop in kvm when ept=0.
#include <unistd.h>
#include <sys/syscall.h>
#include <string.h>
#include <stdint.h>
#include <linux/kvm.h>
#include <fcntl.h>
#include <sys/ioctl.h>
long r[5];
int main()
{
r[2] = open("/dev/kvm", O_RDONLY);
r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
r[4] = ioctl(r[3], KVM_CREATE_VCPU, 7);
ioctl(r[4], KVM_RUN, 0);
}
It doesn't setup the memory regions, mmu_alloc_shadow/direct_roots() in
kvm return 1 when kvm fails to allocate root page table which can result
in beblow infinite loop:
vcpu_run() {
for (;;) {
r = vcpu_enter_guest()::kvm_mmu_reload() returns 1
if (r <= 0)
break;
if (need_resched())
cond_resched();
}
}
This patch fixes it by returning -ENOSPC when there is no available kvm mmu
page for root page table.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 26eeb53cf0 (KVM: MMU: Bail out immediately if there is no available mmu page)
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On AMD platforms, under certain conditions insn_len may be zero on #NPF.
This can happen if a guest gets a page-fault on data access but the HW
table walker is not able to read the instruction page (e.g instruction
page is not present in memory).
Typically, when insn_len is zero, x86_emulate_instruction() walks the
guest page table and fetches the instruction bytes from guest memory.
When SEV is enabled, the guest memory is encrypted with guest-specific
key hence hypervisor will not able to fetch the instruction bytes.
In those cases we simply restart the guest.
I have encountered this issue when running kernbench inside the guest.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Common:
- Python 3 support in kvm_stat
- Accounting of slabs to kmemcg
ARM:
- Optimized arch timer handling for KVM/ARM
- Improvements to the VGIC ITS code and introduction of an ITS reset
ioctl
- Unification of the 32-bit fault injection logic
- More exact external abort matching logic
PPC:
- Support for running hashed page table (HPT) MMU mode on a host that
is using the radix MMU mode; single threaded mode on POWER 9 is
added as a pre-requisite
- Resolution of merge conflicts with the last second 4.14 HPT fixes
- Fixes and cleanups
s390:
- Some initial preparation patches for exitless interrupts and crypto
- New capability for AIS migration
- Fixes
x86:
- Improved emulation of LAPIC timer mode changes, MCi_STATUS MSRs, and
after-reset state
- Refined dependencies for VMX features
- Fixes for nested SMI injection
- A lot of cleanups
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Merge tag 'kvm-4.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Radim Krčmář:
"First batch of KVM changes for 4.15
Common:
- Python 3 support in kvm_stat
- Accounting of slabs to kmemcg
ARM:
- Optimized arch timer handling for KVM/ARM
- Improvements to the VGIC ITS code and introduction of an ITS reset
ioctl
- Unification of the 32-bit fault injection logic
- More exact external abort matching logic
PPC:
- Support for running hashed page table (HPT) MMU mode on a host that
is using the radix MMU mode; single threaded mode on POWER 9 is
added as a pre-requisite
- Resolution of merge conflicts with the last second 4.14 HPT fixes
- Fixes and cleanups
s390:
- Some initial preparation patches for exitless interrupts and crypto
- New capability for AIS migration
- Fixes
x86:
- Improved emulation of LAPIC timer mode changes, MCi_STATUS MSRs,
and after-reset state
- Refined dependencies for VMX features
- Fixes for nested SMI injection
- A lot of cleanups"
* tag 'kvm-4.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (89 commits)
KVM: s390: provide a capability for AIS state migration
KVM: s390: clear_io_irq() requests are not expected for adapter interrupts
KVM: s390: abstract conversion between isc and enum irq_types
KVM: s390: vsie: use common code functions for pinning
KVM: s390: SIE considerations for AP Queue virtualization
KVM: s390: document memory ordering for kvm_s390_vcpu_wakeup
KVM: PPC: Book3S HV: Cosmetic post-merge cleanups
KVM: arm/arm64: fix the incompatible matching for external abort
KVM: arm/arm64: Unify 32bit fault injection
KVM: arm/arm64: vgic-its: Implement KVM_DEV_ARM_ITS_CTRL_RESET
KVM: arm/arm64: Document KVM_DEV_ARM_ITS_CTRL_RESET
KVM: arm/arm64: vgic-its: Free caches when GITS_BASER Valid bit is cleared
KVM: arm/arm64: vgic-its: New helper functions to free the caches
KVM: arm/arm64: vgic-its: Remove kvm_its_unmap_device
arm/arm64: KVM: Load the timer state when enabling the timer
KVM: arm/arm64: Rework kvm_timer_should_fire
KVM: arm/arm64: Get rid of kvm_timer_flush_hwstate
KVM: arm/arm64: Avoid phys timer emulation in vcpu entry/exit
KVM: arm/arm64: Move phys_timer_emulate function
KVM: arm/arm64: Use kvm_arm_timer_set/get_reg for guest register traps
...
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.
However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:
----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()
// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The x86 MMU if full of code that returns 0 and 1 for retry/emulate. Use
the existing RET_MMIO_PF_RETRY/RET_MMIO_PF_EMULATE enum, renaming it to
drop the MMIO part.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It has always annoyed me a bit how SVM_EXIT_NPF is handled by
pf_interception. This is also the only reason behind the
under-documented need_unprotect argument to kvm_handle_page_fault.
Let NPF go straight to kvm_mmu_page_fault, just like VMX
does in handle_ept_violation and handle_ept_misconfig.
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove redundant null checks before calling kmem_cache_destroy.
Found with make coccicheck M=arch/x86/kvm on linux-next tag
next-20170929.
Signed-off-by: Tim Hansen <devtimhansen@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The kvm slabs can consume a significant amount of system memory
and indeed in our production environment we have observed that
a lot of machines are spending significant amount of memory that
can not be left as system memory overhead. Also the allocations
from these slabs can be triggered directly by user space applications
which has access to kvm and thus a buggy application can leak
such memory. So, these caches should be accounted to kmemcg.
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Let's just drop the return.
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
is_last_gpte() is not equivalent to the pseudo-code given in commit
6bb69c9b69 ("KVM: MMU: simplify last_pte_bitmap") because an incorrect
value of last_nonleaf_level may override the result even if level == 1.
It is critical for is_last_gpte() to return true on level == 1 to
terminate page walks. Otherwise memory corruption may occur as level
is used as an index to various data structures throughout the page
walking code. Even though the actual bug would be wherever the MMU is
initialized (as in the previous patch), be defensive and ensure here
that is_last_gpte() returns the correct value.
This patch is also enough to fix CVE-2017-12188.
Fixes: 6bb69c9b69
Cc: stable@vger.kernel.org
Cc: Andy Honig <ahonig@google.com>
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
[Panic if walk_addr_generic gets an incorrect level; this is a serious
bug and it's not worth a WARN_ON where the recovery path might hide
further exploitable issues; suggested by Andrew Honig. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The function updates context->root_level but didn't call
update_last_nonleaf_level so the previous and potentially wrong value
was used for page walks. For example, a zero value of last_nonleaf_level
would allow a potential out-of-bounds access in arch/x86/mmu/paging_tmpl.h's
walk_addr_generic function (CVE-2017-12188).
Fixes: 155a97a3d7
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Currently, in PREEMPT_COUNT=n kernel, kvm_async_pf_task_wait() could call
schedule() to reschedule in some cases. This could result in
accidentally ending the current RCU read-side critical section early,
causing random memory corruption in the guest, or otherwise preempting
the currently running task inside between preempt_disable and
preempt_enable.
The difficulty to handle this well is because we don't know whether an
async PF delivered in a preemptible section or RCU read-side critical section
for PREEMPT_COUNT=n, since preempt_disable()/enable() and rcu_read_lock/unlock()
are both no-ops in that case.
To cure this, we treat any async PF interrupting a kernel context as one
that cannot be preempted, preventing kvm_async_pf_task_wait() from choosing
the schedule() path in that case.
To do so, a second parameter for kvm_async_pf_task_wait() is introduced,
so that we know whether it's called from a context interrupting the
kernel, and the parameter is set properly in all the callsites.
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Common:
- improve heuristic for boosting preempted spinlocks by ignoring VCPUs
in user mode
ARM:
- fix for decoding external abort types from guests
- added support for migrating the active priority of interrupts when
running a GICv2 guest on a GICv3 host
- minor cleanup
PPC:
- expose storage keys to userspace
- merge powerpc/topic/ppc-kvm branch that contains
find_linux_pte_or_hugepte and POWER9 thread management cleanup
- merge kvm-ppc-fixes with a fix that missed 4.13 because of vacations
- fixes
s390:
- merge of topic branch tlb-flushing from the s390 tree to get the
no-dat base features
- merge of kvm/master to avoid conflicts with additional sthyi fixes
- wire up the no-dat enhancements in KVM
- multiple epoch facility (z14 feature)
- Configuration z/Architecture Mode
- more sthyi fixes
- gdb server range checking fix
- small code cleanups
x86:
- emulate Hyper-V TSC frequency MSRs
- add nested INVPCID
- emulate EPTP switching VMFUNC
- support Virtual GIF
- support 5 level page tables
- speedup nested VM exits by packing byte operations
- speedup MMIO by using hardware provided physical address
- a lot of fixes and cleanups, especially nested
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Merge tag 'kvm-4.14-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Radim Krčmář:
"First batch of KVM changes for 4.14
Common:
- improve heuristic for boosting preempted spinlocks by ignoring
VCPUs in user mode
ARM:
- fix for decoding external abort types from guests
- added support for migrating the active priority of interrupts when
running a GICv2 guest on a GICv3 host
- minor cleanup
PPC:
- expose storage keys to userspace
- merge kvm-ppc-fixes with a fix that missed 4.13 because of
vacations
- fixes
s390:
- merge of kvm/master to avoid conflicts with additional sthyi fixes
- wire up the no-dat enhancements in KVM
- multiple epoch facility (z14 feature)
- Configuration z/Architecture Mode
- more sthyi fixes
- gdb server range checking fix
- small code cleanups
x86:
- emulate Hyper-V TSC frequency MSRs
- add nested INVPCID
- emulate EPTP switching VMFUNC
- support Virtual GIF
- support 5 level page tables
- speedup nested VM exits by packing byte operations
- speedup MMIO by using hardware provided physical address
- a lot of fixes and cleanups, especially nested"
* tag 'kvm-4.14-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (67 commits)
KVM: arm/arm64: Support uaccess of GICC_APRn
KVM: arm/arm64: Extract GICv3 max APRn index calculation
KVM: arm/arm64: vITS: Drop its_ite->lpi field
KVM: arm/arm64: vgic: constify seq_operations and file_operations
KVM: arm/arm64: Fix guest external abort matching
KVM: PPC: Book3S HV: Fix memory leak in kvm_vm_ioctl_get_htab_fd
KVM: s390: vsie: cleanup mcck reinjection
KVM: s390: use WARN_ON_ONCE only for checking
KVM: s390: guestdbg: fix range check
KVM: PPC: Book3S HV: Report storage key support to userspace
KVM: PPC: Book3S HV: Fix case where HDEC is treated as 32-bit on POWER9
KVM: PPC: Book3S HV: Fix invalid use of register expression
KVM: PPC: Book3S HV: Fix H_REGISTER_VPA VPA size validation
KVM: PPC: Book3S HV: Fix setting of storage key in H_ENTER
KVM: PPC: e500mc: Fix a NULL dereference
KVM: PPC: e500: Fix some NULL dereferences on error
KVM: PPC: Book3S HV: Protect updates to spapr_tce_tables list
KVM: s390: we are always in czam mode
KVM: s390: expose no-DAT to guest and migration support
KVM: s390: sthyi: remove invalid guest write access
...
The following commit:
d0ec49d4de ("kvm/x86/svm: Support Secure Memory Encryption within KVM")
uses __sme_clr() to remove the C-bit in rsvd_bits(). rsvd_bits() is
just a simple function to return some 1 bits. Applying a mask based
on properties of the host MMU is incorrect. Additionally, the masks
computed by __reset_rsvds_bits_mask also apply to guest page tables,
where the C bit is reserved since we don't emulate SME.
The fix is to clear the C-bit from rsvd_bits_mask array after it has been
populated from __reset_rsvds_bits_mask()
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kvm@vger.kernel.org
Cc: paolo.bonzini@gmail.com
Fixes: d0ec49d ("kvm/x86/svm: Support Secure Memory Encryption within KVM")
Link: http://lkml.kernel.org/r/20170825205540.123531-1-brijesh.singh@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
update_permission_bitmask currently does a 128-iteration loop to,
essentially, compute a constant array. Computing the 8 bits in parallel
reduces it to 16 iterations, and is enough to speed it up substantially
because many boolean operations in the inner loop become constants or
simplify noticeably.
Because update_permission_bitmask is actually the top item in the profile
for nested vmexits, this speeds up an L2->L1 vmexit by about ten thousand
clock cycles, or up to 30%:
before after
cpuid 35173 25954
vmcall 35122 27079
inl_from_pmtimer 52635 42675
inl_from_qemu 53604 44599
inl_from_kernel 38498 30798
outl_to_kernel 34508 28816
wr_tsc_adjust_msr 34185 26818
rd_tsc_adjust_msr 37409 27049
mmio-no-eventfd:pci-mem 50563 45276
mmio-wildcard-eventfd:pci-mem 34495 30823
mmio-datamatch-eventfd:pci-mem 35612 31071
portio-no-eventfd:pci-io 44925 40661
portio-wildcard-eventfd:pci-io 29708 27269
portio-datamatch-eventfd:pci-io 31135 27164
(I wrote a small C program to compare the tables for all values of CR0.WP,
CR4.SMAP and CR4.SMEP, and they match).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Extends the shadow paging code, so that 5 level shadow page
table can be constructed if VM is running in 5 level paging
mode.
Also extends the ept code, so that 5 level ept table can be
constructed if maxphysaddr of VM exceeds 48 bits. Unlike the
shadow logic, KVM should still use 4 level ept table for a VM
whose physical address width is less than 48 bits, even when
the VM is running in 5 level paging mode.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
[Unconditionally reset the MMU context in kvm_cpuid_update.
Changing MAXPHYADDR invalidates the reserved bit bitmasks.
- Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now we have 4 level page table and 5 level page table in 64 bits
long mode, let's rename the PT64_ROOT_LEVEL to PT64_ROOT_4LEVEL,
then we can use PT64_ROOT_5LEVEL for 5 level page table, it's
helpful to make the code more clear.
Also PT64_ROOT_MAX_LEVEL is defined as 4, so that we can just
redefine it to 5 whenever a replacement is needed for 5 level
paging.
Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is currently some confusion between nested and L1 GPAs. The
assignment to "direct" in kvm_mmu_page_fault tries to fix that, but
it is not enough. What this patch does is fence off the MMIO cache
completely when using shadow nested page tables, since we have neither
a GVA nor an L1 GPA to put in the cache. This also allows some
simplifications in kvm_mmu_page_fault and FNAME(page_fault).
The EPT misconfig likewise does not have an L1 GPA to pass to
kvm_io_bus_write, so that must be skipped for guest mode.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[Changed comment to say "GPAs" instead of "L1's physical addresses", as
per David's review. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
When a guest causes a page fault which requires emulation, the
vcpu->arch.gpa_available flag is set to indicate that cr2 contains a
valid GPA.
Currently, emulator_read_write_onepage() makes use of gpa_available flag
to avoid a guest page walk for a known MMIO regions. Lets not limit
the gpa_available optimization to just MMIO region. The patch extends
the check to avoid page walk whenever gpa_available flag is set.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
[Fix EPT=0 according to Wanpeng Li's fix, plus ensure VMX also uses the
new code. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[Moved "ret < 0" to the else brach, as per David's review. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Calling handle_mmio_page_fault() has been unnecessary since commit
e9ee956e31 ("KVM: x86: MMU: Move handle_mmio_page_fault() call to
kvm_mmu_page_fault()", 2016-02-22).
handle_mmio_page_fault() can now be made static.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Bailing out immediately if there is no available mmu page to alloc.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
watchdog: BUG: soft lockup - CPU#5 stuck for 22s! [warn_test:3089]
irq event stamp: 20532
hardirqs last enabled at (20531): [<ffffffff8e9b6908>] restore_regs_and_iret+0x0/0x1d
hardirqs last disabled at (20532): [<ffffffff8e9b7ae8>] apic_timer_interrupt+0x98/0xb0
softirqs last enabled at (8266): [<ffffffff8e9badc6>] __do_softirq+0x206/0x4c1
softirqs last disabled at (8253): [<ffffffff8e083918>] irq_exit+0xf8/0x100
CPU: 5 PID: 3089 Comm: warn_test Tainted: G OE 4.13.0-rc3+ #8
RIP: 0010:kvm_mmu_prepare_zap_page+0x72/0x4b0 [kvm]
Call Trace:
make_mmu_pages_available.isra.120+0x71/0xc0 [kvm]
kvm_mmu_load+0x1cf/0x410 [kvm]
kvm_arch_vcpu_ioctl_run+0x1316/0x1bf0 [kvm]
kvm_vcpu_ioctl+0x340/0x700 [kvm]
? kvm_vcpu_ioctl+0x340/0x700 [kvm]
? __fget+0xfc/0x210
do_vfs_ioctl+0xa4/0x6a0
? __fget+0x11d/0x210
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x23/0xc2
? __this_cpu_preempt_check+0x13/0x20
This can be reproduced readily by ept=N and running syzkaller tests since
many syzkaller testcases don't setup any memory regions. However, if ept=Y
rmode identity map will be created, then kvm_mmu_calculate_mmu_pages() will
extend the number of VM's mmu pages to at least KVM_MIN_ALLOC_MMU_PAGES
which just hide the issue.
I saw the scenario kvm->arch.n_max_mmu_pages == 0 && kvm->arch.n_used_mmu_pages == 1,
so there is one active mmu page on the list, kvm_mmu_prepare_zap_page() fails
to zap any pages, however prepare_zap_oldest_mmu_page() always returns true.
It incurs infinite loop in make_mmu_pages_available() which causes mmu->lock
softlockup.
This patch fixes it by setting the return value of prepare_zap_oldest_mmu_page()
according to whether or not there is mmu page zapped.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This is the same as commit 147277540b ("kvm: svm: Add support for
additional SVM NPF error codes", 2016-11-23), but for Intel processors.
In this case, the exit qualification field's bit 8 says whether the
EPT violation occurred while translating the guest's final physical
address or rather while translating the guest page tables.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 147277540b ("kvm: svm: Add support for additional SVM NPF error
codes", 2016-11-23) added a new error code to aid nested page fault
handling. The commit unprotects (kvm_mmu_unprotect_page) the page when
we get a NPF due to guest page table walk where the page was marked RO.
However, if an L0->L2 shadow nested page table can also be marked read-only
when a page is read only in L1's nested page table. If such a page
is accessed by L2 while walking page tables it can cause a nested
page fault (page table walks are write accesses). However, after
kvm_mmu_unprotect_page we may get another page fault, and again in an
endless stream.
To cover this use case, we qualify the new error_code check with
vcpu->arch.mmu_direct_map so that the error_code check would run on L1
guest, and not the L2 guest. This avoids hitting the above scenario.
Fixes: 147277540b
Cc: stable@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch turns guest_cpuid_has_XYZ(cpuid) into guest_cpuid_has(cpuid,
X86_FEATURE_XYZ), which gets rid of many very similar helpers.
When seeing a X86_FEATURE_*, we can know which cpuid it belongs to, but
this information isn't in common code, so we recreate it for KVM.
Add some BUILD_BUG_ONs to make sure that it runs nicely.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Update the KVM support to work with SME. The VMCB has a number of fields
where physical addresses are used and these addresses must contain the
memory encryption mask in order to properly access the encrypted memory.
Also, use the memory encryption mask when creating and using the nested
page tables.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/89146eccfa50334409801ff20acd52a90fb5efcf.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Adds another flag bit (bit 2) to MSR_KVM_ASYNC_PF_EN. If bit 2 is 1,
async page faults are delivered to L1 as #PF vmexits; if bit 2 is 0,
kvm_can_do_async_pf returns 0 if in guest mode.
This is similar to what svm.c wanted to do all along, but it is only
enabled for Linux as L1 hypervisor. Foreign hypervisors must never
receive async page faults as vmexits, because they'd probably be very
confused about that.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This patch adds the L1 guest async page fault #PF vmexit handler, such
by L1 similar to ordinary async page fault.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[Passed insn parameters to kvm_mmu_page_fault().]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
- Better machine check handling for HV KVM
- Ability to support guests with threads=2, 4 or 8 on POWER9
- Fix for a race that could cause delayed recognition of signals
- Fix for a bug where POWER9 guests could sleep with interrupts pending.
ARM:
- VCPU request overhaul
- allow timer and PMU to have their interrupt number selected from userspace
- workaround for Cavium erratum 30115
- handling of memory poisonning
- the usual crop of fixes and cleanups
s390:
- initial machine check forwarding
- migration support for the CMMA page hinting information
- cleanups and fixes
x86:
- nested VMX bugfixes and improvements
- more reliable NMI window detection on AMD
- APIC timer optimizations
Generic:
- VCPU request overhaul + documentation of common code patterns
- kvm_stat improvements
There is a small conflict in arch/s390 due to an arch-wide field rename.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"PPC:
- Better machine check handling for HV KVM
- Ability to support guests with threads=2, 4 or 8 on POWER9
- Fix for a race that could cause delayed recognition of signals
- Fix for a bug where POWER9 guests could sleep with interrupts pending.
ARM:
- VCPU request overhaul
- allow timer and PMU to have their interrupt number selected from userspace
- workaround for Cavium erratum 30115
- handling of memory poisonning
- the usual crop of fixes and cleanups
s390:
- initial machine check forwarding
- migration support for the CMMA page hinting information
- cleanups and fixes
x86:
- nested VMX bugfixes and improvements
- more reliable NMI window detection on AMD
- APIC timer optimizations
Generic:
- VCPU request overhaul + documentation of common code patterns
- kvm_stat improvements"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (124 commits)
Update my email address
kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS
x86: kvm: mmu: use ept a/d in vmcs02 iff used in vmcs12
kvm: x86: mmu: allow A/D bits to be disabled in an mmu
x86: kvm: mmu: make spte mmio mask more explicit
x86: kvm: mmu: dead code thanks to access tracking
KVM: PPC: Book3S: Fix typo in XICS-on-XIVE state saving code
KVM: PPC: Book3S HV: Close race with testing for signals on guest entry
KVM: PPC: Book3S HV: Simplify dynamic micro-threading code
KVM: x86: remove ignored type attribute
KVM: LAPIC: Fix lapic timer injection delay
KVM: lapic: reorganize restart_apic_timer
KVM: lapic: reorganize start_hv_timer
kvm: nVMX: Check memory operand to INVVPID
KVM: s390: Inject machine check into the nested guest
KVM: s390: Inject machine check into the guest
tools/kvm_stat: add new interactive command 'b'
tools/kvm_stat: add new command line switch '-i'
tools/kvm_stat: fix error on interactive command 'g'
KVM: SVM: suppress unnecessary NMI singlestep on GIF=0 and nested exit
...
EPT A/D was enabled in the vmcs02 EPTP regardless of the vmcs12's EPTP
value. The problem is that enabling A/D changes the behavior of L2's
x86 page table walks as seen by L1. With A/D enabled, x86 page table
walks are always treated as EPT writes.
Commit ae1e2d1082 ("kvm: nVMX: support EPT accessed/dirty bits",
2017-03-30) tried to work around this problem by clearing the write
bit in the exit qualification for EPT violations triggered by page
walks. However, that fixup introduced the opposite bug: page-table walks
that actually set x86 A/D bits were *missing* the write bit in the exit
qualification.
This patch fixes the problem by disabling EPT A/D in the shadow MMU
when EPT A/D is disabled in vmcs12's EPTP.
Signed-off-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Adds the plumbing to disable A/D bits in the MMU based on a new role
bit, ad_disabled. When A/D is disabled, the MMU operates as though A/D
aren't available (i.e., using access tracking faults instead).
To avoid SP -> kvm_mmu_page.role.ad_disabled lookups all over the
place, A/D disablement is now stored in the SPTE. This state is stored
in the SPTE by tweaking the use of SPTE_SPECIAL_MASK for access
tracking. Rather than just setting SPTE_SPECIAL_MASK when an
access-tracking SPTE is non-present, we now always set
SPTE_SPECIAL_MASK for access-tracking SPTEs.
Signed-off-by: Peter Feiner <pfeiner@google.com>
[Use role.ad_disabled even for direct (non-shadow) EPT page tables. Add
documentation and a few MMU_WARN_ONs. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Specify both a mask (i.e., bits to consider) and a value (i.e.,
pattern of bits that indicates a special PTE) for mmio SPTEs. On
Intel, this lets us pack even more information into the
(SPTE_SPECIAL_MASK | EPT_VMX_RWX_MASK) mask we use for access
tracking liberating all (SPTE_SPECIAL_MASK | (non-misconfigured-RWX))
values.
Signed-off-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The MMU always has hardware A bits or access tracking support, thus
it's unnecessary to handle the scenario where we have neither.
Signed-off-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
INFO: task gnome-terminal-:1734 blocked for more than 120 seconds.
Not tainted 4.12.0-rc4+ #8
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
gnome-terminal- D 0 1734 1015 0x00000000
Call Trace:
__schedule+0x3cd/0xb30
schedule+0x40/0x90
kvm_async_pf_task_wait+0x1cc/0x270
? __vfs_read+0x37/0x150
? prepare_to_swait+0x22/0x70
do_async_page_fault+0x77/0xb0
? do_async_page_fault+0x77/0xb0
async_page_fault+0x28/0x30
This is triggered by running both win7 and win2016 on L1 KVM simultaneously,
and then gives stress to memory on L1, I can observed this hang on L1 when
at least ~70% swap area is occupied on L0.
This is due to async pf was injected to L2 which should be injected to L1,
L2 guest starts receiving pagefault w/ bogus %cr2(apf token from the host
actually), and L1 guest starts accumulating tasks stuck in D state in
kvm_async_pf_task_wait() since missing PAGE_READY async_pfs.
This patch fixes the hang by doing async pf when executing L1 guest.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When KVM updates accessed/dirty bits, this hook can be used
to invoke an arch specific function that implements/emulates
dirty logging such as PML.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now use bit 6 of EPTP to optionally enable A/D bits for EPTP. Another
thing to change is that, when EPT accessed and dirty bits are not in use,
VMX treats accesses to guest paging structures as data reads. When they
are in use (bit 6 of EPTP is set), they are treated as writes and the
corresponding EPT dirty bit is set. The MMU didn't know this detail,
so this patch adds it.
We also have to fix up the exit qualification. It may be wrong because
KVM sets bit 6 but the guest might not.
L1 emulates EPT A/D bits using write permissions, so in principle it may
be possible for EPT A/D bits to be used by L1 even though not available
in hardware. The problem is that guest page-table walks will be treated
as reads rather than writes, so they would not cause an EPT violation.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[Fixed typo in walk_addr_generic() comment and changed bit clear +
conditional-set pattern in handle_ept_violation() to conditional-clear]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix typos and add the following to the scripts/spelling.txt:
an user||a user
an userspace||a userspace
I also added "userspace" to the list since it is a common word in Linux.
I found some instances for "an userfaultfd", but I did not add it to the
list. I felt it is endless to find words that start with "user" such as
"userland" etc., so must draw a line somewhere.
Link: http://lkml.kernel.org/r/1481573103-11329-4-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before fast page fault restores an access track PTE back to a regular PTE,
it now also verifies that the restored PTE would grant the necessary
permissions for the faulting access to succeed. If not, it falls back
to the slow page fault path.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Redo the page table walk in fast_page_fault when retrying so that we are
working on the latest PTE even if the hierarchy changes.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reword the comment to hopefully make it more clear.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Instead of the caller including the SPTE_SPECIAL_MASK in the masks being
supplied to kvm_mmu_set_mmio_spte_mask() and kvm_mmu_set_mask_ptes(),
those functions now themselves include the SPTE_SPECIAL_MASK.
Note that bit 63 is now reset in the default MMIO mask.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This change implements lockless access tracking for Intel CPUs without EPT
A bits. This is achieved by marking the PTEs as not-present (but not
completely clearing them) when clear_flush_young() is called after marking
the pages as accessed. When an EPT Violation is generated as a result of
the VM accessing those pages, the PTEs are restored to their original values.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
mmu_spte_update() tracks changes in the accessed/dirty state of
the SPTE being updated and calls kvm_set_pfn_accessed/dirty
appropriately. However, in some cases (e.g. when aging the SPTE),
this shouldn't be done. mmu_spte_update_no_track() is introduced
for use in such cases.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This simplifies mmu_spte_update() a little bit.
The checks for clearing of accessed and dirty bits are refactored into
separate functions, which are used inside both mmu_spte_update() and
mmu_spte_clear_track_bits(), as well as kvm_test_age_rmapp(). The new
helper functions handle both the case when A/D bits are supported in
hardware and the case when they are not.
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This change adds retries into the Fast Page Fault path. Without the
retries, the code still works, but if a retry does end up being needed,
then it will result in a second page fault for the same memory access,
which will cause much more overhead compared to just retrying within the
original fault.
This would be especially useful with the upcoming fast access tracking
change, as that would make it more likely for retries to be needed
(e.g. due to read and write faults happening on different CPUs at
the same time).
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This change renames spte_is_locklessly_modifiable() to
spte_can_locklessly_be_made_writable() to distinguish it from other
forms of lockless modifications. The full set of lockless modifications
is covered by spte_has_volatile_bits().
Signed-off-by: Junaid Shahid <junaids@google.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When using two-dimensional paging, the mmu_page_hash (which provides
lookups for existing kvm_mmu_page structs), becomes imbalanced; with
too many collisions in buckets 0 and 512. This has been seen to cause
mmu_lock to be held for multiple milliseconds in kvm_mmu_get_page on
VMs with a large amount of RAM mapped with 4K pages.
The current hash function uses the lower 10 bits of gfn to index into
mmu_page_hash. When doing shadow paging, gfn is the address of the
guest page table being shadow. These tables are 4K-aligned, which
makes the low bits of gfn a good hash. However, with two-dimensional
paging, no guest page tables are being shadowed, so gfn is the base
address that is mapped by the table. Thus page tables (level=1) have
a 2MB aligned gfn, page directories (level=2) have a 1GB aligned gfn,
etc. This means hashes will only differ in their 10th bit.
hash_64() provides a better hash. For example, on a VM with ~200G
(99458 direct=1 kvm_mmu_page structs):
hash max_mmu_page_hash_collisions
--------------------------------------------
low 10 bits 49847
hash_64 105
perfect 97
While we're changing the hash, increase the table size by 4x to better
support large VMs (further reduces number of collisions in 200G VM to
29).
Note that hash_64() does not provide a good distribution prior to commit
ef703f49a6 ("Eliminate bad hash multipliers from hash_32() and
hash_64()").
Signed-off-by: David Matlack <dmatlack@google.com>
Change-Id: I5aa6b13c834722813c6cca46b8b1ed6f53368ade
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Report the maximum number of mmu_page_hash collisions as a per-VM stat.
This will make it easy to identify problems with the mmu_page_hash in
the future.
Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
AMD hardware adds two additional bits to aid in nested page fault handling.
Bit 32 - NPF occurred while translating the guest's final physical address
Bit 33 - NPF occurred while translating the guest page tables
The guest page tables fault indicator can be used as an aid for nested
virtualization. Using V0 for the host, V1 for the first level guest and
V2 for the second level guest, when both V1 and V2 are using nested paging
there are currently a number of unnecessary instruction emulations. When
V2 is launched shadow paging is used in V1 for the nested tables of V2. As
a result, KVM marks these pages as RO in the host nested page tables. When
V2 exits and we resume V1, these pages are still marked RO.
Every nested walk for a guest page table is treated as a user-level write
access and this causes a lot of NPFs because the V1 page tables are marked
RO in the V0 nested tables. While executing V1, when these NPFs occur KVM
sees a write to a read-only page, emulates the V1 instruction and unprotects
the page (marking it RW). This patch looks for cases where we get a NPF due
to a guest page table walk where the page was marked RO. It immediately
unprotects the page and resumes the guest, leading to far fewer instruction
emulations when nested virtualization is used.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Change unimplemented msrs messages to use pr_debug.
If CONFIG_DYNAMIC_DEBUG is set, then these messages can be
enabled at run time or else -DDEBUG can be used at compile
time to enable them. These messages will still be printed if
ignore_msrs=1.
Signed-off-by: Bandan Das <bsd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
