On Wed, Aug 28, 2024, Colton Lewis wrote:
Hi Mingwei, thanks for reviewing!
Mingwei Zhang mizhang@google.com writes:
On Tue, Aug 13, 2024, Colton Lewis wrote:
This defined the CPUID calls to determine what extensions and properties are available. AMD reference manual names listed below.
- PerfCtrExtCore (six core counters instead of four)
- PerfCtrExtNB (four counters for northbridge events)
- PerfCtrExtL2I (four counters for L2 cache events)
- PerfMonV2 (support for registers to control multiple counters with a single register write)
- LbrAndPmcFreeze (support for freezing last branch recorded stack on performance counter overflow)
- NumPerfCtrCore (number of core counters)
- NumPerfCtrNB (number of northbridge counters)
Signed-off-by: Colton Lewis coltonlewis@google.com
tools/testing/selftests/kvm/include/x86_64/processor.h | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index a0c1440017bb..9d87b5f8974f 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -183,6 +183,9 @@ struct kvm_x86_cpu_feature { #define X86_FEATURE_GBPAGES KVM_X86_CPU_FEATURE(0x80000001, 0, EDX, 26) #define X86_FEATURE_RDTSCP KVM_X86_CPU_FEATURE(0x80000001, 0, EDX, 27) #define X86_FEATURE_LM KVM_X86_CPU_FEATURE(0x80000001, 0, EDX, 29) +#define X86_FEATURE_PERF_CTR_EXT_CORE KVM_X86_CPU_FEATURE(0x80000001, 0, ECX, 23) +#define X86_FEATURE_PERF_CTR_EXT_NB KVM_X86_CPU_FEATURE(0x80000001, 0, ECX, 24) +#define X86_FEATURE_PERF_CTR_EXT_L2I KVM_X86_CPU_FEATURE(0x80000001, 0, ECX, 28)
You won't be testing Northbridge counters and L2I counters, so these two could be optional to the patch.
That's correct. Since it was a small thing to include I thought it best to include and save someone in the future from digging through the reference manual again.
+1. They're defines, i.e. have no meaningful cost. And anything that *might* save me from having to find CPUID entries in the SDM/APM is worth adding.