Re: [PATCH v2 2/5] KVM: selftests: Add timing_info bit support in vmx_pmu_caps_test

Mi, Dapeng
2025-09-11T01:20:21Z

On 9/11/2025 6:03 AM, Sean Christopherson wrote:
> On Fri, Jul 18, 2025, Dapeng Mi wrote:
>> A new bit PERF_CAPABILITIES[17] called "PEBS_TIMING_INFO" bit is added
>> to indicated if PEBS supports to record timing information in a new
>> "Retried Latency" field.
>>
>> Since KVM requires user can only set host consistent PEBS capabilities,
>> otherwise the PERF_CAPABILITIES setting would fail, so add
>> pebs_timing_info bit into "immutable_caps" to block host inconsistent
>> PEBS configuration and cause errors.
> Please explain the removal of anythread_deprecated. AFAICT, something like this
> is accurate:
>
> Opportunistically drop the anythread_deprecated bit. It isn't and likely
> never was a PERF_CAPABILITIES flag, the test's definition snuck in when
> the union was copy+pasted from the kernel's definition.

Yes, would add this in next version. Thanks.

>
>> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
>> Tested-by: Yi Lai <yi1.lai@intel.com>
>> ---
>> tools/testing/selftests/kvm/x86/vmx_pmu_caps_test.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/kvm/x86/vmx_pmu_caps_test.c b/tools/testing/selftests/kvm/x86/vmx_pmu_caps_test.c
>> index a1f5ff45d518..f8deea220156 100644
>> --- a/tools/testing/selftests/kvm/x86/vmx_pmu_caps_test.c
>> +++ b/tools/testing/selftests/kvm/x86/vmx_pmu_caps_test.c
>> @@ -29,7 +29,7 @@ static union perf_capabilities {
>> u64 pebs_baseline:1;
>> u64 perf_metrics:1;
>> u64 pebs_output_pt_available:1;
>> - u64 anythread_deprecated:1;
>> + u64 pebs_timing_info:1;
>> };
>> u64 capabilities;
>> } host_cap;
>> @@ -44,6 +44,7 @@ static const union perf_capabilities immutable_caps = {
>> .pebs_arch_reg = 1,
>> .pebs_format = -1,
>> .pebs_baseline = 1,
>> + .pebs_timing_info = 1,
>> };
>>
>> static const union perf_capabilities format_caps = {
>> --
>> 2.34.1
>>