Re: [PATCH v2 3/3] KVM: SVM: Extend host physical APIC ID field to support more than 8-bit

[Suthikulpanit, Suravee]

On 12/3/2021 11:34 PM, Tom Lendacky wrote:
> On 12/3/21 1:46 AM, Maxim Levitsky wrote:
> > On Thu, 2021-12-02 at 17:58 -0600, Suravee Suthikulpanit wrote:
>
> > > @@ -63,6 +64,7 @@
> > >   static DEFINE_HASHTABLE(svm_vm_data_hash, SVM_VM_DATA_HASH_BITS);
> > >   static u32 next_vm_id = 0;
> > >   static bool next_vm_id_wrapped = 0;
> > > +static u64 avic_host_physical_id_mask;
> > >   static DEFINE_SPINLOCK(svm_vm_data_hash_lock);
> > >   /*
> > > @@ -133,6 +135,20 @@ void avic_vm_destroy(struct kvm *kvm)
> > >       spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
> > >   }
> > > +static void avic_init_host_physical_apicid_mask(void)
> > > +{
> > > +    if (!x2apic_mode) {
> > Wonder why this is a exported  global variable and not function.
> > Not the patch fault though.
> > > +        /* If host is in xAPIC mode, default to only 8-bit mask. */
> > > +        avic_host_physical_id_mask = 0xffULL;
> > > +    } else {
> > > +        u32 count = get_count_order(apic_get_max_phys_apicid());
> > > +
> > > +        avic_host_physical_id_mask = BIT(count) - 1;
> > I think that there were some complains about using this macro and instead encouraged
> > to use 1 << x directly, but I see it used already in other places in avic.c so I don't know.
>
> And I think it should be BIT_ULL() since avic_host_physical_id_mask is a u64.
>
> Thanks,
> Tom

I am not sure about complains on the use of the BIT macros. However, we can just use BIT_ULL() for now
and clean up the whole file at once later if needed.

Regards,
Suravee