RE: [PATCH v9 03/12] perf/x86/intel/pt: Add new bit definitions for Intel PT MSRs

From: Kang, Luwei
Date: Fri Jun 08 2018 - 10:26:17 EST

> > These bit definitions are use for emulate MSRs read/write for KVM. For
> > example, IA32_RTIT_CTL.FabricEn[bit 6] is available only when
> > CPUID.(EAX=14H, ECX=0):ECX[bit 3] = 1. If KVM guest try to set this
> > bit with CPUID.(EAX=14H, ECX=0):ECX[bit3] = 0 a #GP would be injected
> > to KVM guest.
> Do we have anything in the guest that this feature will work with?

It depend on PT driver. KVM need to do some security check if kvm guest (maybe linux or other os) try to set any bits of these MSRs.

Luwei Kang