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| author | Paolo Bonzini <pbonzini@redhat.com> | 2021-12-09 22:10:04 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-01-07 18:44:40 +0300 |
| commit | 006a0f0607e1504950dd8fa3b6ca8e438ec6c9d2 (patch) | |
| tree | f8d63e8f5fdf5ba23e0cf47f88e1ef4a30f8cc5a /arch/x86 | |
| parent | 5b61178cd2fd67890a70ae9febbd4df20bbd8c40 (diff) | |
| download | linux-006a0f0607e1504950dd8fa3b6ca8e438ec6c9d2.tar.xz | |
KVM: x86: avoid out of bounds indices for fixed performance counters
Because IceLake has 4 fixed performance counters but KVM only
supports 3, it is possible for reprogram_fixed_counters to pass
to reprogram_fixed_counter an index that is out of bounds for the
fixed_pmc_events array.
Ultimately intel_find_fixed_event, which is the only place that uses
fixed_pmc_events, handles this correctly because it checks against the
size of fixed_pmc_events anyway. Every other place operates on the
fixed_counters[] array which is sized according to INTEL_PMC_MAX_FIXED.
However, it is cleaner if the unsupported performance counters are culled
early on in reprogram_fixed_counters.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx/pmu_intel.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 1b7456b2177b..d33e9799276e 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -91,7 +91,7 @@ static unsigned intel_find_fixed_event(int idx) u32 event; size_t size = ARRAY_SIZE(fixed_pmc_events); - if (idx >= size) + if (WARN_ON_ONCE(idx >= size)) return PERF_COUNT_HW_MAX; event = fixed_pmc_events[array_index_nospec(idx, size)]; @@ -500,8 +500,9 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu) pmu->nr_arch_fixed_counters = 0; } else { pmu->nr_arch_fixed_counters = - min_t(int, edx.split.num_counters_fixed, - x86_pmu.num_counters_fixed); + min3(ARRAY_SIZE(fixed_pmc_events), + (size_t) edx.split.num_counters_fixed, + (size_t) x86_pmu.num_counters_fixed); edx.split.bit_width_fixed = min_t(int, edx.split.bit_width_fixed, x86_pmu.bit_width_fixed); pmu->counter_bitmask[KVM_PMC_FIXED] = |