Re: [PATCH v2 2/4] KVM: x86: replace kvm_apic_id with kvm_{x,x2}apic_id

David Hildenbrand
2016-12-14T16:16:37Z

> kvm_for_each_vcpu(i, vcpu, kvm)
> if (kvm_apic_present(vcpu))
> - max_id = max(max_id, kvm_apic_id(vcpu->arch.apic));
> + max_id = max(max_id, kvm_x2apic_id(vcpu->arch.apic));
>
> new = kvm_kvzalloc(sizeof(struct kvm_apic_map) +
> sizeof(struct kvm_lapic *) * ((u64)max_id + 1));
> @@ -179,16 +189,23 @@ static void recalculate_apic_map(struct kvm *kvm)
> struct kvm_lapic *apic = vcpu->arch.apic;
> struct kvm_lapic **cluster;
> u16 mask;
> - u32 ldr, aid;
> + u32 ldr;
> + u8 xapic_id;
> + u32 x2apic_id;
>
> if (!kvm_apic_present(vcpu))
> continue;
>
> - aid = kvm_apic_id(apic);

think I'd even prefer here a simple

aid = kvm_xapic_id(apic);
if (apic_x2apic_mode(apic))
aid = kvm_x2apic_id(apic);

that would keep changes minimal and I don't really see any benefit in
the code when splitting handling up.

Patch 4 then simply can fixup setting code

if (aid <= new->max_apic_id && !new->phys_map[aid])
new->phys_map[aid] = apic;

(if I am not missing some important corner case here)

> - ldr = kvm_lapic_get_reg(apic, APIC_LDR);
> + xapic_id = kvm_xapic_id(apic);
> + x2apic_id = kvm_x2apic_id(apic);
>
> - if (aid <= new->max_apic_id)
> - new->phys_map[aid] = apic;
> + if (apic_x2apic_mode(apic) &&
> + x2apic_id <= new->max_apic_id)
> + new->phys_map[x2apic_id] = apic;
> + else if (!apic_x2apic_mode(apic))

This looks good to me.

--

David