diff mbox series

[RFC,v2,42/69] KVM: x86/mmu: Explicitly check for MMIO spte in fast page fault

Message ID 26005d563a9303ecc6ca68a9baea77895a75e8e0.1625186503.git.isaku.yamahata@intel.com (mailing list archive)
State New, archived
Headers show
Series KVM: X86: TDX support | expand

Commit Message

Isaku Yamahata July 2, 2021, 10:04 p.m. UTC 
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(-)

Comments

Paolo Bonzini July 6, 2021, 2:54 p.m. UTC | #1 
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>
diff mbox series

Patch

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;
 
 		/*