[PATCH 6.12 224/567] KVM: SVM: Mark VMCB_NPT as dirty on nested VMRUN

Greg Kroah-Hartman
2026-01-06T17:26:33Z

From: Jim Mattson <jmattson@google.com>

commit 7c8b465a1c91f674655ea9cec5083744ec5f796a upstream.

Mark the VMCB_NPT bit as dirty in nested_vmcb02_prepare_save()
on every nested VMRUN.

If L1 changes the PAT MSR between two VMRUN instructions on the same
L1 vCPU, the g_pat field in the associated vmcb02 will change, and the
VMCB_NPT clean bit should be cleared.

Fixes: 4bb170a5430b ("KVM: nSVM: do not mark all VMCB02 fields dirty on nested vmexit")
Cc: stable@vger.kernel.org
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20250922162935.621409-3-jmattson@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kvm/svm/nested.c | 1 +
1 file changed, 1 insertion(+)

--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -546,6 +546,7 @@ static void nested_vmcb02_prepare_save(s
struct kvm_vcpu *vcpu = &svm->vcpu;

nested_vmcb02_compute_g_pat(svm);
+ vmcb_mark_dirty(vmcb02, VMCB_NPT);

/* Load the nested guest state */
if (svm->nested.vmcb12_gpa != svm->nested.last_vmcb12_gpa) {