LAPIC_XEN_VECTOR
idt_allocmap[LAPIC_XEN_VECTOR] = 1;
idt_vec_set(LAPIC_XEN_VECTOR, Xintr_xen_upcall);
xhp.value = HVM_CALLBACK_VECTOR(LAPIC_XEN_VECTOR);
DPRINTF(", idtvec %d", LAPIC_XEN_VECTOR);
sc->sc_irq = LAPIC_XEN_VECTOR;