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KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022

Browse source 
CPUID leaf 0x80000022 i.e. ExtPerfMonAndDbg advertises some new
performance monitoring features for AMD processors.

Bit 0 of EAX indicates support for Performance Monitoring Version 2
(PerfMonV2) features. If found to be set during PMU initialization,
the EBX bits of the same CPUID function can be used to determine
the number of available PMCs for different PMU types.

Expose the relevant bits via KVM_GET_SUPPORTED_CPUID so that
guests can make use of the PerfMonV2 features.

Co-developed-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230603011058.1038821-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Like Xu 2023-06-02 18:10:58 -07:00 committed by Sean Christopherson
parent 4a2771895c
commit 94cdeebd82
2 changed files with 31 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

28
arch/x86/kvm/cpuid.c
View file

@ -734,6 +734,10 @@ void kvm_set_cpu_caps(void)
F(NULL_SEL_CLR_BASE) | F(AUTOIBRS) | 0 /* PrefetchCtlMsr */
);
kvm_cpu_cap_init_kvm_defined(CPUID_8000_0022_EAX,
F(PERFMON_V2)
);
/*
* Synthesize "LFENCE is serializing" into the AMD-defined entry in
* KVM's supported CPUID if the feature is reported as supported by the
@ -1128,7 +1132,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
entry->edx = 0;
break;
case 0x80000000:
entry->eax = min(entry->eax, 0x80000021);
entry->eax = min(entry->eax, 0x80000022);
/*
* Serializing LFENCE is reported in a multitude of ways, and
* NullSegClearsBase is not reported in CPUID on Zen2; help
@ -1233,6 +1237,28 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
entry->ebx = entry->ecx = entry->edx = 0;
cpuid_entry_override(entry, CPUID_8000_0021_EAX);
break;
/* AMD Extended Performance Monitoring and Debug */
case 0x80000022: {
union cpuid_0x80000022_ebx ebx;
entry->ecx = entry->edx = 0;
if (!enable_pmu || !kvm_cpu_cap_has(X86_FEATURE_PERFMON_V2)) {
entry->eax = entry->ebx;
break;
}
cpuid_entry_override(entry, CPUID_8000_0022_EAX);
if (kvm_cpu_cap_has(X86_FEATURE_PERFMON_V2))
ebx.split.num_core_pmc = kvm_pmu_cap.num_counters_gp;
else if (kvm_cpu_cap_has(X86_FEATURE_PERFCTR_CORE))
ebx.split.num_core_pmc = AMD64_NUM_COUNTERS_CORE;
else
ebx.split.num_core_pmc = AMD64_NUM_COUNTERS;
entry->ebx = ebx.full;
break;
}
/*Add support for Centaur's CPUID instruction*/
case 0xC0000000:
/*Just support up to 0xC0000004 now*/

4
arch/x86/kvm/svm/svm.c
View file

@ -5036,6 +5036,10 @@ static __init void svm_set_cpu_caps(void)
kvm_pmu_cap.num_counters_gp);
else
kvm_cpu_cap_check_and_set(X86_FEATURE_PERFCTR_CORE);
if (kvm_pmu_cap.version != 2 ||
!kvm_cpu_cap_has(X86_FEATURE_PERFCTR_CORE))
kvm_cpu_cap_clear(X86_FEATURE_PERFMON_V2);
}
/* CPUID 0x8000001F (SME/SEV features) */