EXT_IRQ_SERVICE_SIG
vcpu->arch.sie_block->eic = EXT_IRQ_SERVICE_SIG;
rc = put_guest_lc(vcpu, EXT_IRQ_SERVICE_SIG, (u16 *)__LC_EXT_INT_CODE);
rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
} while (get_lowcore()->ext_int_code != EXT_IRQ_SERVICE_SIG);