From: Sean Christopherson seanjc@google.com
commit ef318b9edf66a082f23d00d79b70c17b4c055a26 upstream.
Use the MMU's role to get its effective SMEP value when injecting a fault into the guest. When walking L1's (nested) NPT while L2 is active, vCPU state will reflect L2, whereas NPT uses the host's (L1 in this case) CR0, CR4, EFER, etc... If L1 and L2 have different settings for SMEP and L1 does not have EFER.NX=1, this can result in an incorrect PFEC.FETCH when injecting #NPF.
Fixes: e57d4a356ad3 ("KVM: Add instruction fetch checking when walking guest page table") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson seanjc@google.com Message-Id: 20210622175739.3610207-5-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kvm/mmu/paging_tmpl.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -471,8 +471,7 @@ retry_walk:
error: errcode |= write_fault | user_fault; - if (fetch_fault && (mmu->nx || - kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))) + if (fetch_fault && (mmu->nx || mmu->mmu_role.ext.cr4_smep)) errcode |= PFERR_FETCH_MASK;
walker->fault.vector = PF_VECTOR;