linux-kernel - [PATCH v13 03/10] KVM: vmx/pmu: Initialize vcpu perf_capabilities once in intel_pmu

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Message-Id: <20200726153229.27149-5-like.xu@linux.intel.com>
Date:   Sun, 26 Jul 2020 23:32:22 +0800
From:   Like Xu <like.xu@...ux.intel.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>, kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org,
        Like Xu <like.xu@...ux.intel.com>
Subject: [PATCH v13 03/10] KVM: vmx/pmu: Initialize vcpu perf_capabilities once in intel_pmu_init()

The guest hypervisor may configure MSR_IA32_PERF_CAPABILITIES to unmask
some vmx-supported bits in vcpu->arch.perf_capabilities, and the requested
value could affect the exposure of features in the intel_pmu_refresh().

Refactoring its initialization path clears the way for the above usage.

Signed-off-by: Like Xu <like.xu@...ux.intel.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 6 +++---
 arch/x86/kvm/x86.c           | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index a886a47daebd..f8083ecf8c7b 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -327,7 +327,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 	pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
 	pmu->version = 0;
 	pmu->reserved_bits = 0xffffffff00200000ull;
-	vcpu->arch.perf_capabilities = 0;
 
 	entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
 	if (!entry)
@@ -340,8 +339,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 		return;
 
 	perf_get_x86_pmu_capability(&x86_pmu);
-	if (guest_cpuid_has(vcpu, X86_FEATURE_PDCM))
-		vcpu->arch.perf_capabilities = vmx_get_perf_capabilities();
 
 	pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,
 					 x86_pmu.num_counters_gp);
@@ -401,6 +398,9 @@ static void intel_pmu_init(struct kvm_vcpu *vcpu)
 		pmu->fixed_counters[i].idx = i + INTEL_PMC_IDX_FIXED;
 		pmu->fixed_counters[i].current_config = 0;
 	}
+
+	vcpu->arch.perf_capabilities = guest_cpuid_has(vcpu, X86_FEATURE_PDCM) ?
+		vmx_get_perf_capabilities() : 0;
 }
 
 static void intel_pmu_reset(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c79953b49c77..8a58d0355a99 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2871,7 +2871,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 
 		vcpu->arch.perf_capabilities = data;
-
+		kvm_pmu_refresh(vcpu);
 		return 0;
 		}
 	case MSR_EFER:
-- 
2.21.3