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authorJim Mattson <jmattson@google.com>2019-09-30 16:38:54 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2019-10-01 15:15:06 +0200
commite1fba49cc1e965a3dacd897367ba1e7b340cf0f4 (patch)
treeebcdba25065b7eae3fd591016a9d40aa673ac963 /arch
parent833b45de69a6016c4b0cebe6765d526a31a81580 (diff)
downloadlinux-e1fba49cc1e965a3dacd897367ba1e7b340cf0f4.tar.bz2
kvm: vmx: Limit guest PMCs to those supported on the host
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx/pmu_intel.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 4dea0e0e7e39..3e9c059099e9 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -262,6 +262,7 @@ 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;
@@ -283,8 +284,10 @@ 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);
@@ -294,7 +297,7 @@ 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;
}