Re: [PATCH 1/2] KVM: vmx, pmu: accept 0 for absent MSRs when host-initiated

[Yang, Weijiang]

On 6/1/2022 4:54 PM, Paolo Bonzini wrote:
> On 5/31/22 20:37, Sean Christopherson wrote:
> > > +
> > >           /*
> > >            * Writing depth MSR from guest could either setting the
> > >            * MSR or resetting the LBR records with the side-effect.
> > > @@ -535,6 +542,8 @@ static int intel_pmu_set_msr(struct kvm_vcpu 
> > > *vcpu, struct msr_data *msr_info)
> > >       case MSR_ARCH_LBR_CTL:
> > >           if (!arch_lbr_ctl_is_valid(vcpu, data))
> > >               break;
> > > +        if (!guest_cpuid_has(vcpu, X86_FEATURE_ARCH_LBR))
> > > +            return 0;
> >
> > Similar bug here.
> >
> > Can we just punt this out of kvm/queue until its been properly reviewed?
>
> Yes, I agree.  I have started making some changes and pushed the 
> result to kvm/arch-lbr-for-weijiang.
>
> Most of the MSR handling is rewritten (and untested).
>
> The nested VMX handling was also completely broken so I just removed 
> it.  Instead, KVM should be adjusted so that it does not whine.

Noted, I'll run tests based on it, thanks a lot!

Has the branch been pushed? I cannot see it.

> Paolo