FAILED: patch "[PATCH] KVM: nSVM: Refactor checking LBRV enablement in vmcb12 into a" failed to apply to 6.12-stable tree

FAILED: patch "[PATCH] KVM: nSVM: Refactor checking LBRV enablement in vmcb12 into a" failed to apply to 6.12-stable tree

[gregkh]

The patch below does not apply to the 6.12-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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 290c8d82023ab0e1d2782d37136541e017174d7c
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026050313-thorn-escapade-d954@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 290c8d82023ab0e1d2782d37136541e017174d7c Mon Sep 17 00:00:00 2001
From: Yosry Ahmed <yosry@kernel.org>
Date: Tue, 3 Mar 2026 00:34:00 +0000
Subject: [PATCH] KVM: nSVM: Refactor checking LBRV enablement in vmcb12 into a
 helper

Refactor the vCPU cap and vmcb12 flag checks into a helper. The
unlikely() annotation is dropped, it's unlikely (huh) to make a
difference and the CPU will probably predict it better on its own.

CC: stable@vger.kernel.org
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-7-yosry@kernel.org
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 7a472d7c6e98..d419fd516fa9 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -640,6 +640,12 @@ void nested_vmcb02_compute_g_pat(struct vcpu_svm *svm)
 	svm->nested.vmcb02.ptr->save.g_pat = svm->vmcb01.ptr->save.g_pat;
 }
 
+static bool nested_vmcb12_has_lbrv(struct kvm_vcpu *vcpu)
+{
+	return guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
+		(to_svm(vcpu)->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
+}
+
 static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12)
 {
 	bool new_vmcb12 = false;
@@ -704,8 +710,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
 		vmcb_mark_dirty(vmcb02, VMCB_DR);
 	}
 
-	if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
-		     (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+	if (nested_vmcb12_has_lbrv(vcpu)) {
 		/*
 		 * Reserved bits of DEBUGCTL are ignored.  Be consistent with
 		 * svm_set_msr's definition of reserved bits.
@@ -1233,8 +1238,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 	if (!nested_exit_on_intr(svm))
 		kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
 
-	if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
-		     (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
+	if (nested_vmcb12_has_lbrv(vcpu)) {
 		svm_copy_lbrs(&vmcb12->save, &vmcb02->save);
 	} else {
 		svm_copy_lbrs(&vmcb01->save, &vmcb02->save);