[PATCH 5/7] KVM: VMX: Use vcpu_get_perf_capabilities() to get guest-visible value

Sean Christopherson
2022-06-11T00:58:21Z

Use vcpu_get_perf_capabilities() when querying MSR_IA32_PERF_CAPABILITIES
from the guest's perspective, e.g. to update the vPMU and to determine
which MSRs exist. If userspace ignores MSR_IA32_PERF_CAPABILITIES but
clear X86_FEATURE_PDCM, the guest should see '0'.

Fixes: 902caeb6841a ("KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS")
Fixes: c59a1f106f5c ("KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS")
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/pmu_intel.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index b1aae60cf061..53ccba896e77 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -199,7 +199,7 @@ static bool intel_pmu_is_valid_lbr_msr(struct kvm_vcpu *vcpu, u32 index)
static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
- u64 perf_capabilities = vcpu->arch.perf_capabilities;
+ u64 perf_capabilities;
int ret;

switch (msr) {
@@ -210,12 +210,13 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
ret = pmu->version > 1;
break;
case MSR_IA32_PEBS_ENABLE:
- ret = perf_capabilities & PERF_CAP_PEBS_FORMAT;
+ ret = vcpu_get_perf_capabilities(vcpu) & PERF_CAP_PEBS_FORMAT;
break;
case MSR_IA32_DS_AREA:
ret = guest_cpuid_has(vcpu, X86_FEATURE_DS);
break;
case MSR_PEBS_DATA_CFG:
+ perf_capabilities = vcpu_get_perf_capabilities(vcpu);
ret = (perf_capabilities & PERF_CAP_PEBS_BASELINE) &&
((perf_capabilities & PERF_CAP_PEBS_FORMAT) > 3);
break;
@@ -515,6 +516,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
struct kvm_cpuid_entry2 *entry;
union cpuid10_eax eax;
union cpuid10_edx edx;
+ u64 perf_capabilities;
u64 counter_mask;
int i;

@@ -599,8 +601,9 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
if (lbr_desc->records.nr)
bitmap_set(pmu->all_valid_pmc_idx, INTEL_PMC_IDX_FIXED_VLBR, 1);

- if (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_FORMAT) {
- if (vcpu->arch.perf_capabilities & PERF_CAP_PEBS_BASELINE) {
+ perf_capabilities = vcpu_get_perf_capabilities(vcpu);
+ if (perf_capabilities & PERF_CAP_PEBS_FORMAT) {
+ if (perf_capabilities & PERF_CAP_PEBS_BASELINE) {
pmu->pebs_enable_mask = counter_mask;
pmu->reserved_bits &= ~ICL_EVENTSEL_ADAPTIVE;
for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
--
2.36.1.476.g0c4daa206d-goog