/* * DOMID_IO is used to restrict page-table updates to mapping I/O memory. * Although no Foreign Domain need be specified to map I/O pages, DOMID_IO * is useful to ensure that no mappings to the OS's own heap are accidentally * installed. (e.g., in Linux this could cause havoc as reference counts * aren't adjusted on the I/O-mapping code path). * This only makes sense in MMUEXT_SET_FOREIGNDOM, but in that context can * be specified by any calling domain. */