| Message ID | 20241104094119.4131-2-dongli.zhang@oracle.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | target/i386/kvm/pmu: Enhancement, Bugfix and Cleanup | expand |
Hi Dongli, On Mon, Nov 04, 2024 at 01:40:16AM -0800, Dongli Zhang wrote: > Date: Mon, 4 Nov 2024 01:40:16 -0800 > From: Dongli Zhang <dongli.zhang@oracle.com> > Subject: [PATCH 1/7] target/i386: disable PerfMonV2 when PERFCORE > unavailable > X-Mailer: git-send-email 2.43.5 > > When the PERFCORE is disabled with "-cpu host,-perfctr-core", it is > reflected in in guest dmesg. > > [ 0.285136] Performance Events: AMD PMU driver. > > However, the guest cpuid indicates the PerfMonV2 is still available. > > CPU: > Extended Performance Monitoring and Debugging (0x80000022): > AMD performance monitoring V2 = true > AMD LBR V2 = false > AMD LBR stack & PMC freezing = false > number of core perf ctrs = 0x6 (6) > number of LBR stack entries = 0x0 (0) > number of avail Northbridge perf ctrs = 0x0 (0) > number of available UMC PMCs = 0x0 (0) > active UMCs bitmask = 0x0 > > Disable PerfMonV2 in cpuid when PERFCORE is disabled. > > Fixes: 209b0ac12074 ("target/i386: Add PerfMonV2 feature bit") > Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> > --- > target/i386/cpu.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 3baa95481f..4490a7a8d6 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -7103,6 +7103,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, > *eax = *ebx = *ecx = *edx = 0; > /* AMD Extended Performance Monitoring and Debug */ > if (kvm_enabled() && cpu->enable_pmu && > + (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_PERFCORE) && > (env->features[FEAT_8000_0022_EAX] & CPUID_8000_0022_EAX_PERFMON_V2)) { > *eax |= CPUID_8000_0022_EAX_PERFMON_V2; > *ebx |= kvm_arch_get_supported_cpuid(cs->kvm_state, index, count, You can define dependency like this: diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 3baa95481fbc..99c69ec9f369 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1803,6 +1803,10 @@ static FeatureDep feature_dependencies[] = { .from = { FEAT_7_1_EDX, CPUID_7_1_EDX_AVX10 }, .to = { FEAT_24_0_EBX, ~0ull }, }, + { + .from = { FEAT_8000_0001_ECX, CPUID_EXT3_PERFCORE }, + .to = { FEAT_8000_0022_EAX, CPUID_8000_0022_EAX_PERFMON_V2 } + } }; typedef struct X86RegisterInfo32 { --- Does this meet your needs? Regards, Zhao
Hi Zhao, > > You can define dependency like this: > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 3baa95481fbc..99c69ec9f369 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -1803,6 +1803,10 @@ static FeatureDep feature_dependencies[] = { > .from = { FEAT_7_1_EDX, CPUID_7_1_EDX_AVX10 }, > .to = { FEAT_24_0_EBX, ~0ull }, > }, > + { > + .from = { FEAT_8000_0001_ECX, CPUID_EXT3_PERFCORE }, > + .to = { FEAT_8000_0022_EAX, CPUID_8000_0022_EAX_PERFMON_V2 } > + } > }; > > typedef struct X86RegisterInfo32 { > > --- > Does this meet your needs? > Thank you very much for the suggestion. Yes, this works. The PERFCORE is a prerequisite of PERFMON_V2 (according to Linux kernel source code). 1403 static int __init amd_core_pmu_init(void) 1404 { 1405 union cpuid_0x80000022_ebx ebx; 1406 u64 even_ctr_mask = 0ULL; 1407 int i; 1408 1409 if (!boot_cpu_has(X86_FEATURE_PERFCTR_CORE)) 1410 return 0; If you don't mind, I will send the v2 with your Suggested-by. Thank you very much! Dongli Zhang
> Thank you very much for the suggestion. > > Yes, this works. The PERFCORE is a prerequisite of PERFMON_V2 (according to > Linux kernel source code). > > 1403 static int __init amd_core_pmu_init(void) > 1404 { > 1405 union cpuid_0x80000022_ebx ebx; > 1406 u64 even_ctr_mask = 0ULL; > 1407 int i; > 1408 > 1409 if (!boot_cpu_has(X86_FEATURE_PERFCTR_CORE)) > 1410 return 0; > > > If you don't mind, I will send the v2 with your Suggested-by. > > Thank you very much! Sure, welcome! :) -Zhao > Dongli Zhang
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 3baa95481f..4490a7a8d6 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -7103,6 +7103,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, *eax = *ebx = *ecx = *edx = 0; /* AMD Extended Performance Monitoring and Debug */ if (kvm_enabled() && cpu->enable_pmu && + (env->features[FEAT_8000_0001_ECX] & CPUID_EXT3_PERFCORE) && (env->features[FEAT_8000_0022_EAX] & CPUID_8000_0022_EAX_PERFMON_V2)) { *eax |= CPUID_8000_0022_EAX_PERFMON_V2; *ebx |= kvm_arch_get_supported_cpuid(cs->kvm_state, index, count,
When the PERFCORE is disabled with "-cpu host,-perfctr-core", it is reflected in in guest dmesg. [ 0.285136] Performance Events: AMD PMU driver. However, the guest cpuid indicates the PerfMonV2 is still available. CPU: Extended Performance Monitoring and Debugging (0x80000022): AMD performance monitoring V2 = true AMD LBR V2 = false AMD LBR stack & PMC freezing = false number of core perf ctrs = 0x6 (6) number of LBR stack entries = 0x0 (0) number of avail Northbridge perf ctrs = 0x0 (0) number of available UMC PMCs = 0x0 (0) active UMCs bitmask = 0x0 Disable PerfMonV2 in cpuid when PERFCORE is disabled. Fixes: 209b0ac12074 ("target/i386: Add PerfMonV2 feature bit") Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> --- target/i386/cpu.c | 1 + 1 file changed, 1 insertion(+)