From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Yosry Ahmed <yosry@kernel.org>,
Shivansh Dhiman <shivansh.dhiman@amd.com>,
Nikunj A Dadhania <nikunj@amd.com>,
Ravi Bangoria <ravi.bangoria@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: [PATCH v6 07/12] KVM: SVM: Add helper to query if LBR virtualization needs to be enabled
Date: Wed, 30 Sep 2026 12:36:29 -0700 [thread overview]
Message-ID: <20260930193634.3415089-8-seanjc@google.com> (raw)
In-Reply-To: <20260930193634.3415089-1-seanjc@google.com>
Extract the logic for determining whether or not LBR virtualization needs
to be enabled into a helper in anticipation of growing the list of features
that depend on LBR virtualization.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/svm/svm.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0eb1623052c1..775eccfb7b24 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -875,13 +875,22 @@ static void __svm_disable_lbrv(struct kvm_vcpu *vcpu)
to_svm(vcpu)->vmcb->control.misc_ctl2 &= ~SVM_MISC2_ENABLE_V_LBR;
}
+static bool svm_need_lbr_virtualization(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ if (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR)
+ return true;
+
+ return is_guest_mode(vcpu) && guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
+ (svm->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR);
+}
+
void svm_update_lbrv(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
bool current_enable_lbrv = svm->vmcb->control.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR;
- bool enable_lbrv = (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR) ||
- (is_guest_mode(vcpu) && guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
- (svm->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR));
+ bool enable_lbrv = svm_need_lbr_virtualization(vcpu);
if (enable_lbrv && !current_enable_lbrv)
__svm_enable_lbrv(vcpu);
--
2.56.0.rc1.315.gc6ed9934b7-goog
next prev parent reply other threads:[~2026-09-30 19:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-30 19:36 [PATCH v6 00/12] KVM: x86: Bus Lock Detect fixes and SVM support Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 01/12] KVM: x86: Preserve DR6.BLD (Bus Lock Detect) when delivering #DB payload Sean Christopherson
2026-09-30 23:46 ` Shivansh Dhiman
2026-09-30 19:36 ` [PATCH v6 02/12] KVM: x86: Rename kvm_dr6_fixed() => kvm_get_dr6_fixed_1() Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 03/12] KVM: Return an "unsigned long", not "u64" for the fixed-1 DR6 bits Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 04/12] KVM: x86: Force fixed-1 bits in DR6 after synchronizing with hardware Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 05/12] KVM: x86: Set guest's fixed-1 DR6 bits when delivering #DB payload Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 06/12] KVM: x86: Kill off DR6_FIXED_1 to prevent future misuse Sean Christopherson
2026-09-30 19:36 ` Sean Christopherson [this message]
2026-09-30 19:36 ` [PATCH v6 08/12] KVM: nSVM: Disable LBRV in nested control cache when unsupported Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 09/12] KVM: nSVM: Open code check on LBR virtualization being enabled in vmcb12 Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 10/12] KVM: nSVM: Don't assume all active-low bits DR6 are fixed-1 Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 11/12] KVM: SVM: Add a vCPU-aware helper to get supported DEBUGCTL bits Sean Christopherson
2026-09-30 19:36 ` [PATCH v6 12/12] KVM: SVM: Add support for virtualizating Bus Lock Detect Sean Christopherson
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