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SubjectRe: [PATCH 2/3] KVM: x86: Avoid guest page table walk when gpa_available is set
2017-08-18 09:57+0200, David Hildenbrand:
>
> > +++ 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)

It does, I took the liberty to change that.

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

Thanks.

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