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| author | Sean Christopherson <seanjc@google.com> | 2024-08-31 03:15:30 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-09-10 06:16:30 +0300 |
| commit | 620525739521376a65a690df899e1596d56791f8 (patch) | |
| tree | a332d0d8358d12089cea267bc7a408e69ce049f2 /arch/x86 | |
| parent | b299c273c06f005976cdc1b9e9299d492527607e (diff) | |
| download | linux-620525739521376a65a690df899e1596d56791f8.tar.xz | |
KVM: x86: Remove manual pfn lookup when retrying #PF after failed emulation
Drop the manual pfn look when retrying an instruction that KVM failed to
emulation in response to a #PF due to a write-protected gfn. Now that KVM
sets EMULTYPE_ALLOW_RETRY_PF if and only if the page fault hit a write-
protected gfn, i.e. if and only if there's a writable memslot, there's no
need to redo the lookup to avoid retrying an instruction that failed on
emulated MMIO (no slot, or a write to a read-only slot).
I.e. KVM will never attempt to retry an instruction that failed on
emulated MMIO, whereas that was not the case prior to the introduction of
RET_PF_WRITE_PROTECTED.
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/r/20240831001538.336683-16-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/x86.c | 18 |
1 files changed, 0 insertions, 18 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index a7961f8a6429..1e9c5ef4a9f5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8865,7 +8865,6 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, int emulation_type) { gpa_t gpa = cr2_or_gpa; - kvm_pfn_t pfn; if (!(emulation_type & EMULTYPE_ALLOW_RETRY_PF)) return false; @@ -8886,23 +8885,6 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, } /* - * Do not retry the unhandleable instruction if it faults on the - * readonly host memory, otherwise it will goto a infinite loop: - * retry instruction -> write #PF -> emulation fail -> retry - * instruction -> ... - */ - pfn = gfn_to_pfn(vcpu->kvm, gpa_to_gfn(gpa)); - - /* - * If the instruction failed on the error pfn, it can not be fixed, - * report the error to userspace. - */ - if (is_error_noslot_pfn(pfn)) - return false; - - kvm_release_pfn_clean(pfn); - - /* * If emulation may have been triggered by a write to a shadowed page * table, unprotect the gfn (zap any relevant SPTEs) and re-enter the * guest to let the CPU re-execute the instruction in the hope that the |