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KVM: x86/mmu: Get CR4.SMEP from MMU, not vCPU, in shadow page fault

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Use the current MMU instead of vCPU state to query CR4.SMEP when handling
a page fault.  In the nested NPT case, the current CR4.SMEP reflects L2,
whereas the page fault is shadowing L1's NPT, which uses L1's hCR4.
Practically speaking, this is a nop a NPT walks are always user faults,
i.e. this code will never be reached, but fix it up for consistency.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210622175739.3610207-54-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2021-06-22 10:57:38 -07:00
committed by Paolo Bonzini
parent fdaa293598
commit 9a65d0b70f
1 changed files with 1 additions and 1 deletions
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arch/x86/kvm/mmu/paging_tmpl.h
+1 -1
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@@ -903,7 +903,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
* then we should prevent the kernel from executing it
* if SMEP is enabled.
*/
if (kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))
if (is_cr4_smep(vcpu->arch.mmu))
walker.pte_access &= ~ACC_EXEC_MASK;
}