Commit a7557539 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: x86/pmu: preserve IA32_PERF_CAPABILITIES across CPUID refresh 



Once MSR_IA32_PERF_CAPABILITIES is changed via vmx_set_msr(), the
value should not be changed by cpuid(). To ensure that the new value
is kept, the default initialization path is moved to intel_pmu_init().
The effective value of the MSR will be 0 if PDCM is clear, however.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 252e365e

arch/x86/kvm/vmx/pmu_intel.c

+10 −6
Original line number Diff line number Diff line
@@ -152,12 +152,17 @@ static struct kvm_pmc *intel_rdpmc_ecx_to_pmc(struct kvm_vcpu *vcpu, 
	return &counters[array_index_nospec(idx, num_counters)];

}



static inline bool fw_writes_is_enabled(struct kvm_vcpu *vcpu)

static inline u64 vcpu_get_perf_capabilities(struct kvm_vcpu *vcpu)

{

	if (!guest_cpuid_has(vcpu, X86_FEATURE_PDCM))

		return false;

		return 0;



	return vcpu->arch.perf_capabilities & PMU_CAP_FW_WRITES;

	return vcpu->arch.perf_capabilities;

}



static inline bool fw_writes_is_enabled(struct kvm_vcpu *vcpu)

{

	return (vcpu_get_perf_capabilities(vcpu) & PMU_CAP_FW_WRITES) != 0;

}



static inline struct kvm_pmc *get_fw_gp_pmc(struct kvm_pmu *pmu, u32 msr)
@@ -327,7 +332,6 @@ 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 +344,6 @@ 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);
@@ -405,6 +407,8 @@ 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 = vmx_get_perf_capabilities();

}



static void intel_pmu_reset(struct kvm_vcpu *vcpu)