FAILED: patch "[PATCH] KVM: SVM: Mark VMCB_NPT as dirty on nested VMRUN" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] KVM: SVM: Mark VMCB_NPT as dirty on nested VMRUN" failed to apply to 5.15-stable tree

[gregkh]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 7c8b465a1c91f674655ea9cec5083744ec5f796a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025122929-riveter-outreach-a5e9@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7c8b465a1c91f674655ea9cec5083744ec5f796a Mon Sep 17 00:00:00 2001
From: Jim Mattson <jmattson@google.com>
Date: Mon, 22 Sep 2025 09:29:23 -0700
Subject: [PATCH] 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 35cea27862c6..83de3456df70 100644
--- 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) {

[PATCH 5.15.y] KVM: SVM: Mark VMCB_NPT as dirty on nested VMRUN

[Sasha Levin]

From: Jim Mattson <jmattson@google.com>

[ Upstream commit 7c8b465a1c91f674655ea9cec5083744ec5f796a ]

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>
[ adapted vmcb02 local variable to svm->vmcb direct access pattern ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/nested.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index c24d7860bd53..5f9f14eb61c4 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -456,6 +456,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
 	bool new_vmcb12 = false;
 
 	nested_vmcb02_compute_g_pat(svm);
+	vmcb_mark_dirty(svm->vmcb, VMCB_NPT);
 
 	/* Load the nested guest state */
 	if (svm->nested.vmcb12_gpa != svm->nested.last_vmcb12_gpa) {
-- 
2.51.0

Re: [PATCH 5.15.y] KVM: SVM: Mark VMCB_NPT as dirty on nested VMRUN

[Sean Christopherson]

On Wed, Dec 31, 2025, Sasha Levin wrote:
> From: Jim Mattson <jmattson@google.com>
> 
> [ Upstream commit 7c8b465a1c91f674655ea9cec5083744ec5f796a ]
> 
> 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>
> [ adapted vmcb02 local variable to svm->vmcb direct access pattern ]

FWIW, I double checked that vmcb02 is indeed guaranteed to be the active vmcb.

> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---

Acked-by: Sean Christopherson <seanjc@google.com>