AVIC_VCPU_IDX_MASK
#define AVIC_GATAG_TO_VCPUIDX(x) (x & AVIC_VCPU_IDX_MASK)
((vcpu_idx) & AVIC_VCPU_IDX_MASK))
static_assert(__AVIC_GATAG(AVIC_VM_ID_MASK, AVIC_VCPU_IDX_MASK) == -1u);