linux-kernel - [PATCH v12 17/17] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64

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Date:   Fri,  4 Mar 2022 17:04:27 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v12 17/17] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64

From: Like Xu <likexu@...cent.com>

The CPUID features PDCM, DS and DTES64 are required for PEBS feature.
KVM would expose CPUID feature PDCM, DS and DTES64 to guest when PEBS
is supported in the KVM on the Ice Lake server platforms.

Originally-by: Andi Kleen <ak@...ux.intel.com>
Co-developed-by: Kan Liang <kan.liang@...ux.intel.com>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
Co-developed-by: Luwei Kang <luwei.kang@...el.com>
Signed-off-by: Luwei Kang <luwei.kang@...el.com>
Signed-off-by: Like Xu <likexu@...cent.com>
---
 arch/x86/kvm/vmx/capabilities.h | 28 +++++++++++++++++-----------
 arch/x86/kvm/vmx/vmx.c          | 15 +++++++++++++++
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index 3f430e218375..0e3929ddf9c8 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -6,6 +6,7 @@
 
 #include "lapic.h"
 #include "x86.h"
+#include "pmu.h"
 
 extern bool __read_mostly enable_vpid;
 extern bool __read_mostly flexpriority_enabled;
@@ -385,23 +386,28 @@ static inline bool vmx_pt_mode_is_host_guest(void)
 	return pt_mode == PT_MODE_HOST_GUEST;
 }
 
+static inline bool vmx_pebs_supported(void)
+{
+	return boot_cpu_has(X86_FEATURE_PEBS) && kvm_pmu_cap.pebs_ept;
+}
+
 static inline u64 vmx_get_perf_capabilities(void)
 {
-	u64 perf_cap = 0;
-
-	if (!enable_pmu)
-		return perf_cap;
+	u64 perf_cap = PMU_CAP_FW_WRITES;
+	u64 host_perf_cap = 0;
 
 	if (boot_cpu_has(X86_FEATURE_PDCM))
-		rdmsrl(MSR_IA32_PERF_CAPABILITIES, perf_cap);
+		rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap);
 
-	perf_cap &= PMU_CAP_LBR_FMT;
+	perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT;
 
-	/*
-	 * Since counters are virtualized, KVM would support full
-	 * width counting unconditionally, even if the host lacks it.
-	 */
-	return PMU_CAP_FW_WRITES | perf_cap;
+	if (vmx_pebs_supported()) {
+		perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
+		if ((perf_cap & PERF_CAP_PEBS_FORMAT) < 4)
+			perf_cap &= ~PERF_CAP_PEBS_BASELINE;
+	}
+
+	return perf_cap;
 }
 
 static inline u64 vmx_supported_debugctl(void)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 7ae0a82a2a78..89899d1a865d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2247,6 +2247,17 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			if (!cpuid_model_is_consistent(vcpu))
 				return 1;
 		}
+		if (data & PERF_CAP_PEBS_FORMAT) {
+			if ((data & PERF_CAP_PEBS_MASK) !=
+			    (vmx_get_perf_capabilities() & PERF_CAP_PEBS_MASK))
+				return 1;
+			if (!guest_cpuid_has(vcpu, X86_FEATURE_DS))
+				return 1;
+			if (!guest_cpuid_has(vcpu, X86_FEATURE_DTES64))
+				return 1;
+			if (!cpuid_model_is_consistent(vcpu))
+				return 1;
+		}
 		ret = kvm_set_msr_common(vcpu, msr_info);
 		break;
 
@@ -7416,6 +7427,10 @@ static __init void vmx_set_cpu_caps(void)
 		kvm_cpu_cap_clear(X86_FEATURE_INVPCID);
 	if (vmx_pt_mode_is_host_guest())
 		kvm_cpu_cap_check_and_set(X86_FEATURE_INTEL_PT);
+	if (vmx_pebs_supported()) {
+		kvm_cpu_cap_check_and_set(X86_FEATURE_DS);
+		kvm_cpu_cap_check_and_set(X86_FEATURE_DTES64);
+	}
 
 	if (!enable_sgx) {
 		kvm_cpu_cap_clear(X86_FEATURE_SGX);
-- 
2.35.1