> >> Can you elaborate on this, what information do we need besides > >> MSR_IA32_VMX_MISC[14]? > > > > Enable Intel PT in guest depend on SECONDARY_EXEC_PT_USE_GPA, EPT, > > MSR_IA32_VMX_MISC[14] and the capability of " PT_CAP_topa_output" on > > hardware. PT driver will return " -ENODEV" if hardware not support > > "PT_CAP_topa_output". > > I actually don't understand why PT_CAP_topa_output matters for the purpose of enabling PT in the guest. However you still need > __pt_cap_get() in the CPUID checks. Hi Paolo, I think we should expose Intel Processor Trace to guest that can be detected and initialized. But without "PT_CAP_topa_output" Intel PT can't work in Linux. So I add this feature as precondition. About why need this check in driver I think Alexander may know the reason. Thanks, Luwei Kang > > Paolo
