Leaf 0xb is reserved by AMD, and uniformly hidden from guests by the toolstack
logic and hypervisor PV logic. The previous dynamic logic filled in the
x2APIC ID for all HVM guests.
In practice, leaf 0xb is tightly linked with x2APIC, and x2APIC is offered to
guests on AMD hardware, as Xen's APIC
>>> On 10.03.17 at 17:44, wrote:
> @@ -938,6 +927,21 @@ void guest_cpuid(const struct vcpu *v, uint32_t leaf,
> }
> break;
>
> +case 0xb:
> +/*
> + * In principle, this leaf is Intel-only. In practice, it is tightly
> + * coupled with x2apic, and we
