[RFC PATCH v3 32/59] KVM: x86/mmu: Explicitly check for MMIO spte in fast page fault

isaku.yamahata
2021-11-25T00:23:07Z

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 5305d1d9a976..01569913f1f0 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3186,7 +3186,7 @@ static int fast_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
break;

sp = sptep_to_sp(sptep);
- if (!is_last_spte(spte, sp->role.level))
+ if (!is_last_spte(spte, sp->role.level) || is_mmio_spte(spte))
break;

/*
--
2.25.1