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SubjectRe: [PATCH 2/3] KVM: x86: Avoid guest page table walk when gpa_available is set
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> +++ b/arch/x86/kvm/x86.c
> @@ -4657,25 +4657,18 @@ static int emulator_read_write_onepage(unsigned long addr, void *val,
> */
> if (vcpu->arch.gpa_available &&
> emulator_can_use_gpa(ctxt) &&
> - vcpu_is_mmio_gpa(vcpu, addr, exception->address, write) &&
> - (addr & ~PAGE_MASK) == (exception->address & ~PAGE_MASK)) {
> - gpa = exception->address;
> - goto mmio;
> + (addr & ~PAGE_MASK) == (vcpu->arch.gpa_val & ~PAGE_MASK)) {
> + gpa = vcpu->arch.gpa_val;
> + ret = vcpu_is_mmio_gpa(vcpu, addr, gpa, write);
> + } else {
> + ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write);
> }
>
> - ret = vcpu_mmio_gva_to_gpa(vcpu, addr, &gpa, exception, write);
> -
> if (ret < 0)
> return X86EMUL_PROPAGATE_FAULT;

just wondering if it makes sense to move this into the else branch (as
it logically only belongs to vcpu_mmio_gva_to_gpa)

Reviewed-by: David Hildenbrand <david@redhat.com>

--

Thanks,

David

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