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KVM: x86/pmu: Limit the maximum number of supported AMD GP counters

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The AMD PerfMonV2 specification allows for a maximum of 16 GP counters,
but currently only 6 pairs of MSRs are accepted by KVM.

While AMD64_NUM_COUNTERS_CORE is already equal to 6, increasing without
adjusting msrs_to_save_all[] could result in out-of-bounds accesses.
Therefore introduce a macro (named KVM_AMD_PMC_MAX_GENERIC) to
refer to the number of counters supported by KVM.

Signed-off-by: Like Xu <likexu@tencent.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20220919091008.60695-3-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Like Xu 2022-09-19 17:10:08 +08:00 committed by Paolo Bonzini
parent 4f1fa2a1bb
commit 556f3c9ad7
3 changed files with 8 additions and 3 deletions
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1
arch/x86/include/asm/kvm_host.h
View File

@ -506,6 +506,7 @@ struct kvm_pmc {
#define MSR_ARCH_PERFMON_PERFCTR_MAX (MSR_ARCH_PERFMON_PERFCTR0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
#define MSR_ARCH_PERFMON_EVENTSEL_MAX (MSR_ARCH_PERFMON_EVENTSEL0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
#define KVM_PMC_MAX_FIXED 3
#define KVM_AMD_PMC_MAX_GENERIC 6
struct kvm_pmu {
unsigned nr_arch_gp_counters;
unsigned nr_arch_fixed_counters;

7
arch/x86/kvm/svm/pmu.c
View File

@ -192,9 +192,10 @@ static void amd_pmu_init(struct kvm_vcpu *vcpu)
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
int i;
BUILD_BUG_ON(AMD64_NUM_COUNTERS_CORE > INTEL_PMC_MAX_GENERIC);
BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > AMD64_NUM_COUNTERS_CORE);
BUILD_BUG_ON(KVM_AMD_PMC_MAX_GENERIC > INTEL_PMC_MAX_GENERIC);
for (i = 0; i < AMD64_NUM_COUNTERS_CORE ; i++) {
for (i = 0; i < KVM_AMD_PMC_MAX_GENERIC ; i++) {
pmu->gp_counters[i].type = KVM_PMC_GP;
pmu->gp_counters[i].vcpu = vcpu;
pmu->gp_counters[i].idx = i;
@ -207,7 +208,7 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
int i;
for (i = 0; i < AMD64_NUM_COUNTERS_CORE; i++) {
for (i = 0; i < KVM_AMD_PMC_MAX_GENERIC; i++) {
struct kvm_pmc *pmc = &pmu->gp_counters[i];
pmc_stop_counter(pmc);

3
arch/x86/kvm/x86.c
View File

@ -1452,10 +1452,13 @@ static const u32 msrs_to_save_all[] = {
MSR_K7_EVNTSEL0, MSR_K7_EVNTSEL1, MSR_K7_EVNTSEL2, MSR_K7_EVNTSEL3,
MSR_K7_PERFCTR0, MSR_K7_PERFCTR1, MSR_K7_PERFCTR2, MSR_K7_PERFCTR3,
/* This part of MSRs should match KVM_AMD_PMC_MAX_GENERIC. */
MSR_F15H_PERF_CTL0, MSR_F15H_PERF_CTL1, MSR_F15H_PERF_CTL2,
MSR_F15H_PERF_CTL3, MSR_F15H_PERF_CTL4, MSR_F15H_PERF_CTL5,
MSR_F15H_PERF_CTR0, MSR_F15H_PERF_CTR1, MSR_F15H_PERF_CTR2,
MSR_F15H_PERF_CTR3, MSR_F15H_PERF_CTR4, MSR_F15H_PERF_CTR5,
MSR_IA32_XFD, MSR_IA32_XFD_ERR,
};