• Like Xu's avatar
    KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS · 902caeb6
    Like Xu authored
    If IA32_PERF_CAPABILITIES.PEBS_BASELINE [bit 14] is set, the adaptive
    PEBS is supported. The PEBS_DATA_CFG MSR and adaptive record enable
    bits (IA32_PERFEVTSELx.Adaptive_Record and IA32_FIXED_CTR_CTRL.
    FCx_Adaptive_Record) are also supported.
    
    Adaptive PEBS provides software the capability to configure the PEBS
    records to capture only the data of interest, keeping the record size
    compact. An overflow of PMCx results in generation of an adaptive PEBS
    record with state information based on the selections specified in
    MSR_PEBS_DATA_CFG.By default, the record only contain the Basic group.
    
    When guest adaptive PEBS is enabled, the IA32_PEBS_ENABLE MSR will
    be added to the perf_guest_switch_msr() and switched during the VMX
    transitions just like CORE_PERF_GLOBAL_CTRL MSR.
    
    According to Intel SDM, software is recommended to  PEBS Baseline
    when the following is true. IA32_PERF_CAPABILITIES.PEBS_BASELINE[14]
    && IA32_PERF_CAPABILITIES.PEBS_FMT[11:8] ≥ 4.
    Co-developed-by: default avatarLuwei Kang <luwei.kang@intel.com>
    Signed-off-by: default avatarLuwei Kang <luwei.kang@intel.com>
    Signed-off-by: default avatarLike Xu <likexu@tencent.com>
    Message-Id: <20220411101946.20262-12-likexu@tencent.com>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    902caeb6
pmu_intel.c 22.4 KB