• Sean Christopherson's avatar
    KVM: x86/pmu: Squash period for checkpointed events based on host HLE/RTM · 5a4f8b30
    Sean Christopherson authored
    Zero out the sampling period for checkpointed events if the host supports
    HLE or RTM, i.e. supports transactions and thus checkpointed events, not
    based on whether the vCPU vendor model is Intel.  Perf's refusal to allow
    a sample period for checkpointed events is based purely on whether or not
    the CPU supports HLE/RTM transactions, i.e. perf has no knowledge of the
    vCPU vendor model.
    
    Note, it is _extremely_ unlikely that the existing code is a problem in
    real world usage, as there are far, far bigger hurdles that would need to
    be cleared to support cross-vendor vPMUs.  The motivation is mainly to
    eliminate the use of guest_cpuid_is_intel(), in order to get to a state
    where KVM pivots on AMD vs. Intel compatibility, i.e. doesn't check for
    exactly vendor==Intel except in rare circumstances (i.e. for CPU quirks).
    
    Cc: Like Xu <like.xu.linux@gmail.com>
    Link: https://lore.kernel.org/r/20240405235603.1173076-4-seanjc@google.comSigned-off-by: default avatarSean Christopherson <seanjc@google.com>
    5a4f8b30
pmu.c 29.1 KB