Re: [PATCH v4 21/25] KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()

From: Sean Christopherson
Date: Thu Jul 28 2022 - 18:34:39 EST


On Fri, Jul 29, 2022, Paolo Bonzini wrote:
> On 7/22/22 00:56, Sean Christopherson wrote:
> > Except the errata are based on FMS and the FMS exposed to the L1 hypervisor may
> > not be the real FMS.
> >
> > But that's moot, because they_should_ be fully emulated by KVM anyways; KVM
> > runs L2 with a MSR value modified by perf, not the raw MSR value requested by L1.
> >
> > Of course KVM screws things up and fails to clear the flag in entry controls...
> > All exit controls are emulated so at least KVM gets those right.
>
> Can you send this as a separate patch?

Will do.