On Monday, September 19, 2022 10:41 PM, Liang, Kan wrote: > Another fake event? We have to specially handle it in the perf code. I don't > think it's a clean way for perf. We can check the patch later. I think it should be clean, like the LBR side. > > > - on VMEnter: > > -- perf_disable_event_local(host_event); > > -- perf_enable_event_local(guest_event); > > - on VMExit: > > -- perf_disable_event_local(guest_event); > > -- perf_enable_event_local(host_event); > > Why we cannot use the same way as the perf core driver to switch the MSRs in > the VMCS? The current MSR switching list from VMCS isn’t fast, should be the last resort when really necessary. > > You just need one generic function, perf_guest_get_msrs(), for both PT and > core driver. If you have to disable PT explicitly before VMCS, I think you can do > it in the PT specific perf_guest_get_msrs(). The disable is done via " Clear IA32_RTIT_CTL" VMExit control. It can ensure PT disabled in time on VMExit, so no need to go through perf_guest_get_msrs. Thanks, Wei
