linux-kernel - [RFC v1 8/9] KVM: X86: MSR_IA32_PERF

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Date:   Thu, 29 Aug 2019 13:34:08 +0800
From:   Luwei Kang <luwei.kang@...el.com>
To:     pbonzini@...hat.com, rkrcmar@...hat.com
Cc:     sean.j.christopherson@...el.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        x86@...nel.org, ak@...ux.intel.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Luwei Kang <luwei.kang@...el.com>
Subject: [RFC v1 8/9] KVM: X86: MSR_IA32_PERF_CAPABILITIES MSR emulation

Expose some bits of definition which relate with enable
PEBS to KVM guest especially PEBS via PT feature.

Signed-off-by: Luwei Kang <luwei.kang@...el.com>
---
 arch/x86/include/asm/kvm_host.h  |  1 +
 arch/x86/include/asm/msr-index.h |  3 +++
 arch/x86/kvm/vmx/vmx.c           | 14 ++++++++++++++
 3 files changed, 18 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2d9b0f9..94af338 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -576,6 +576,7 @@ struct kvm_vcpu_arch {
 	u64 ia32_xss;
 	u64 microcode_version;
 	u64 arch_capabilities;
+	u64 ia32_perf_capabilities;
 
 	/*
 	 * Paging state of the vcpu
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 6321acb..4932dec 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -137,6 +137,9 @@
 #define MSR_IA32_PEBS_ENABLE		0x000003f1
 #define MSR_PEBS_DATA_CFG		0x000003f2
 #define MSR_IA32_DS_AREA		0x00000600
+#define MSR_IA32_PERF_CAP_PEBS_TRAP	(1UL << 6)
+#define MSR_IA32_PERF_CAP_PEBS_ARCH_REG	(1UL << 7)
+#define MSR_IA32_PERF_CAP_PEBS_REC_FMT	(0xfUL << 8)
 #define MSR_IA32_PERF_CAP_PEBS_OUTPUT_PT	(1UL << 16)
 #define MSR_IA32_PERF_CAPABILITIES	0x00000345
 #define MSR_PEBS_LD_LAT_THRESHOLD	0x000003f6
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index dbff8f0..71e3d42 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1737,6 +1737,16 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		msr_info->data = vcpu->arch.ia32_xss;
 		break;
+	case MSR_IA32_PERF_CAPABILITIES:
+		if (!vmx_pdcm_supported() || !vmx_pebs_supported())
+			return 1;
+		rdmsrl(MSR_IA32_PERF_CAPABILITIES, msr_info->data);
+		msr_info->data = msr_info->data &
+			(MSR_IA32_PERF_CAP_PEBS_TRAP |
+			 MSR_IA32_PERF_CAP_PEBS_ARCH_REG |
+			 MSR_IA32_PERF_CAP_PEBS_REC_FMT |
+			 MSR_IA32_PERF_CAP_PEBS_OUTPUT_PT);
+		break;
 	case MSR_IA32_RTIT_CTL:
 		if (pt_mode != PT_MODE_HOST_GUEST)
 			return 1;
@@ -1981,6 +1991,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		else
 			clear_atomic_switch_msr(vmx, MSR_IA32_XSS);
 		break;
+	case MSR_IA32_PERF_CAPABILITIES:
+		if (!vmx_pdcm_supported() || !vmx_pebs_supported())
+			return 1;
+		break;
 	case MSR_IA32_RTIT_CTL:
 		if ((pt_mode != PT_MODE_HOST_GUEST) ||
 			vmx_rtit_ctl_check(vcpu, data) ||
-- 
1.8.3.1