Re: [PATCH v2 07/25] KVM: VMX: Set intercept for FRED MSRs

[Xin Li]

> > > When FRED is advertised to a guest, KVM should allow FRED SSP MSRs
> > > accesses through disabling FRED SSP MSRs interception no matter whether
> > > supervisor shadow stacks are enabled or not.
> >
> > KVM doesn't necessarily need to disabling MSR interception, e.g. if 
> > the expectation
> > is that the guest will rarely/never access the MSRs when CET is 
> > unsupported, then
> > we're likely better off going with a trap-and-emulate model.  KVM 
> > needs to emulate
> > RDMSR and WRMSR no matter what, e.g. in case the guest triggers a 
> > WRMSR when KVM
> > is emulating, and so that userspace can get/set MSR values.
> >
> > And this means that yes, FRED virtualization needs to land after CET 
> > virtualization,
> > otherwise managing the conflicts/dependencies will be a nightmare.

I still plan to send another iteration of the FRED patch set for review,
however I haven't seen your x86 KVM changes land into Linus' tree, it
will happen soon, right?

> No argument.