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SubjectRe: [RFC PATCH v2 42/69] KVM: x86/mmu: Explicitly check for MMIO spte in fast page fault
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On 03/07/21 00:04, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> Explicity check for an MMIO spte in the fast page fault flow. TDX will
> use a not-present entry for MMIO sptes, which can be mistaken for an
> access-tracked spte since both have SPTE_SPECIAL_MASK set.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> arch/x86/kvm/mmu/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 990ee645b8a2..631b92e6e9ba 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -3060,7 +3060,7 @@ static int fast_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
> break;
>
> sp = sptep_to_sp(iterator.sptep);
> - if (!is_last_spte(spte, sp->role.level))
> + if (!is_last_spte(spte, sp->role.level) || is_mmio_spte(spte))
> break;
>
> /*
>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

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