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[53/54] KVM: x86/mmu: Get CR4.SMEP from MMU, not vCPU, in shadow page fault

Message ID 20210622175739.3610207-54-seanjc@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: x86/mmu: Bug fixes and summer cleaning | expand

Commit Message

Sean Christopherson June 22, 2021, 5:57 p.m. UTC
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>
 arch/x86/kvm/mmu/paging_tmpl.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 260a9c06d764..a79353fc6efd 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -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;