Re: [PATCH 2/2] KVM: SVM: Extend host physical APIC ID field to support more than 8-bit

[Suthikulpanit, Suravee]

On 11/10/2021 11:48 AM, Sean Christopherson wrote:
>   Wed, Nov 10, 2021, Suravee Suthikulpanit wrote:
> > diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> > index 989685098b3e..0b066bb5149d 100644
> > --- a/arch/x86/kvm/svm/svm.c
> > +++ b/arch/x86/kvm/svm/svm.c
> > @@ -1031,6 +1031,12 @@ static __init int svm_hardware_setup(void)
> >   			nrips = false;
> >   	}
> >   
> > +	if (avic) {
> > +		r = avic_init_host_physical_apicid_mask();
> > +		if (r)
> > +			avic = false;
> > +	}
> Haven't yet dedicated any brain cells to the rest of the patch, but this can be
> written as
>
> 	if (avic && avic_init_host_physical_apicid_mask())
> 		avic = false;
>
> or
>
> 	avic = avic && !avic_init_host_physical_apicid_mask();
>
> But looking at the context below, combining everything would be preferable.  I
> would say split out the enable_apicv part to make it more obvious that enable_apicv
> is merely a reflection of avic.
>
> 	avic = avic && npt_enabled && boot_cpu_has(X86_FEATURE_AVIC) &&
> 	       !avic_init_host_physical_apicid_mask();
> 	enable_apicv = avic;

Yes, we can do that. I'll update the logic in V2.

Thanks,
Suravee