From: Jim Mattson jmattson@google.com
[ Upstream commit e1fba49cc1e965a3dacd897367ba1e7b340cf0f4 ]
KVM can only virtualize as many PMCs as the host supports.
Limit the number of generic counters and fixed counters to the number of corresponding counters supported on the host, rather than to INTEL_PMC_MAX_GENERIC and INTEL_PMC_MAX_FIXED, respectively.
Note that INTEL_PMC_MAX_GENERIC is currently 32, which exceeds the 18 contiguous MSR indices reserved by Intel for event selectors. Since the existing code relies on a contiguous range of MSR indices for event selectors, it can't possibly work for more than 18 general purpose counters.
Fixes: f5132b01386b5a ("KVM: Expose a version 2 architectural PMU to a guests") Signed-off-by: Jim Mattson jmattson@google.com Reviewed-by: Marc Orr marcorr@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kvm/pmu_intel.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/pmu_intel.c b/arch/x86/kvm/pmu_intel.c index 2729131fe9bfc..170ca7eeb15b7 100644 --- a/arch/x86/kvm/pmu_intel.c +++ b/arch/x86/kvm/pmu_intel.c @@ -260,6 +260,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) static void intel_pmu_refresh(struct kvm_vcpu *vcpu) { struct kvm_pmu *pmu = vcpu_to_pmu(vcpu); + struct x86_pmu_capability x86_pmu; struct kvm_cpuid_entry2 *entry; union cpuid10_eax eax; union cpuid10_edx edx; @@ -281,8 +282,10 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) if (!pmu->version) return;
+ perf_get_x86_pmu_capability(&x86_pmu); + pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters, - INTEL_PMC_MAX_GENERIC); + x86_pmu.num_counters_gp); pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << eax.split.bit_width) - 1; pmu->available_event_types = ~entry->ebx & ((1ull << eax.split.mask_length) - 1); @@ -292,7 +295,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) } else { pmu->nr_arch_fixed_counters = min_t(int, edx.split.num_counters_fixed, - INTEL_PMC_MAX_FIXED); + x86_pmu.num_counters_fixed); pmu->counter_bitmask[KVM_PMC_FIXED] = ((u64)1 << edx.split.bit_width_fixed) - 1; }