Messages in this thread | | | From | "Kang, Luwei" <> | Subject | RE: [PATCH v7 05/13] perf/x86/intel/pt: Introduce a new function to get capability of Intel PT | Date | Thu, 3 May 2018 12:30:44 +0000 |
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> > > > New function __pt_cap_get() will be invoked in KVM to check if a > > > > specific capability is availiable in KVM guest. > > > > Another function pt_cap_get() can only check the hardware > > > > capabilities but this may different with KVM guest because some > > > > features may not be exposed to guest. > > > > > > Do we really need both in KVM? > > > > Yes, KVM need get host capability to estimate if can expose this > > feature to guest > > 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".
Thanks, Luwei Kang
> > Thanks, > -- > Alex
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