On 2024-04-11 1:04 p.m., Sean Christopherson wrote: > On Fri, Jan 26, 2024, Xiong Zhang wrote: >> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> >> >> Define and apply the PERF_PMU_CAP_VPMU_PASSTHROUGH flag for the version 4 >> and later PMUs > > Why? I get that is an RFC, but it's not at all obvious to me why this needs to > take a dependency on v4+. The IA32_PERF_GLOBAL_STATUS_RESET/SET MSRs are introduced in v4. They are used in the save/restore of PMU state. Please see PATCH 23/41. So it's limited to v4+ for now. Thanks, Kan
