diff mbox series

[v8,37/81] KVM: x86: disable gpa_available optimization for fetch and page-walk NPF/EPT violations

Message ID 20200330101308.21702-38-alazar@bitdefender.com (mailing list archive)
State New, archived
Headers show
Series VM introspection | expand

Commit Message

Adalbert Lazăr March 30, 2020, 10:12 a.m. UTC 
From: Mircea Cîrjaliu <mcirjaliu@bitdefender.com>

This change is needed because the introspection tool can write-protect
guest page tables or exec-protect heap/stack pages.

Signed-off-by: Mircea Cîrjaliu <mcirjaliu@bitdefender.com>
Signed-off-by: Adalbert Lazăr <alazar@bitdefender.com>
---
 arch/x86/kvm/mmu/mmu.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 7c6368ddc6a5..35be9f2a2fc7 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5536,8 +5536,13 @@  int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,
 	if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa)))
 		return RET_PF_RETRY;
 
-	/* With shadow page tables, fault_address contains a GVA or nGPA.  */
-	if (vcpu->arch.mmu->direct_map) {
+	/*
+	 * With shadow page tables, fault_address contains a GVA or nGPA.
+	 * On a fetch fault, fault_address contains the instruction pointer.
+	 */
+	if (vcpu->arch.mmu->direct_map &&
+	    likely(!(error_code & PFERR_FETCH_MASK)) &&
+	    (error_code & PFERR_GUEST_FINAL_MASK)) {
 		vcpu->arch.gpa_available = true;
 		vcpu->arch.gpa_val = cr2_or_gpa;
 	}