linux-kernel - [PATCH 08/15] KVM: x86: Add Arch LBR MSRs to msrs_to_save

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Date:   Wed, 31 Aug 2022 18:34:31 -0400
From:   Yang Weijiang <weijiang.yang@...el.com>
To:     pbonzini@...hat.com, seanjc@...gle.com, kvm@...r.kernel.org
Cc:     like.xu.linux@...il.com, kan.liang@...ux.intel.com,
        wei.w.wang@...el.com, linux-kernel@...r.kernel.org
Subject: [PATCH 08/15] KVM: x86: Add Arch LBR MSRs to msrs_to_save_all list

Arch LBR MSR_ARCH_LBR_DEPTH and MSR_ARCH_LBR_CTL are queried by
userspace application before it wants to {save|restore} the Arch LBR
data. Other LBR related data MSRs are omitted here intentionally due
to lengthy list(32*3). Userspace can still use KVM_{GET|SET}_MSRS to
access them if necessary.

Suggested-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
Reviewed-by: Jim Mattson <jmattson@...gle.com>
---
 arch/x86/kvm/x86.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 92ff5f7d944b..b3d2a7ad1d18 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1452,6 +1452,7 @@ static const u32 msrs_to_save_all[] = {
 	MSR_F15H_PERF_CTR3, MSR_F15H_PERF_CTR4, MSR_F15H_PERF_CTR5,
 	MSR_IA32_XFD, MSR_IA32_XFD_ERR,
 	MSR_IA32_XSS,
+	MSR_ARCH_LBR_CTL, MSR_ARCH_LBR_DEPTH,
 };
 
 static u32 msrs_to_save[ARRAY_SIZE(msrs_to_save_all)];
@@ -3839,6 +3840,8 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_PEBS_ENABLE:
 	case MSR_IA32_DS_AREA:
 	case MSR_PEBS_DATA_CFG:
+	case MSR_ARCH_LBR_CTL:
+	case MSR_ARCH_LBR_DEPTH:
 	case MSR_F15H_PERF_CTL0 ... MSR_F15H_PERF_CTR5:
 		if (kvm_pmu_is_valid_msr(vcpu, msr))
 			return kvm_pmu_set_msr(vcpu, msr_info);
@@ -3942,6 +3945,8 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_PEBS_ENABLE:
 	case MSR_IA32_DS_AREA:
 	case MSR_PEBS_DATA_CFG:
+	case MSR_ARCH_LBR_CTL:
+	case MSR_ARCH_LBR_DEPTH:
 	case MSR_F15H_PERF_CTL0 ... MSR_F15H_PERF_CTR5:
 		if (kvm_pmu_is_valid_msr(vcpu, msr_info->index))
 			return kvm_pmu_get_msr(vcpu, msr_info);
@@ -6948,6 +6953,11 @@ static void kvm_init_msr_list(void)
 			if (!kvm_caps.supported_xss)
 				continue;
 			break;
+		case MSR_ARCH_LBR_DEPTH:
+		case MSR_ARCH_LBR_CTL:
+			if (!kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR))
+				continue;
+			break;
 		default:
 			break;
 		}
-- 
2.27.0