mp_register_ioapic
extern int mp_register_ioapic(int id, u32 address, u32 gsi_base,
mp_register_ioapic(ioapic->id, ioapic->address, ioapic->global_irq_base,
ret = mp_register_ioapic(ioapic_id, phys_addr, gsi_base, &cfg);
mp_register_ioapic(++ioapic_id, r.start, gsi_top, &cfg);
mp_register_ioapic(0, 0xfec00000, gsi_top, &ioapic_cfg);
mp_register_ioapic(m->apicid, m->apicaddr, gsi_top, &cfg);