KVM: SVM: Mark VMCB_NPT as dirty on nested VMRUN

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>

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 35cea27862c60df7b75296de5ed14cacd05584e4..83de3456df7087e0f97f4765b66bcb2f00d15fca 100644 (file)
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -613,6 +613,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
        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) {