xen_intr_describe
xen_intr_describe(DPCPU_ID_GET(i, xendebug_handler), "d%d", i);
xen_intr_describe(pcpu->irq_handle, "c%d", i);
xen_intr_describe(ipi_handle[idx], "%s", ipi->description);
xen_intr_describe(xen_intr_handle_t port_handle, const char *fmt, ...)