An embodiment of the present invention is a technique to provide cache
support for direct memory access address translation. A cache structure
stores cached entries used in address translation of a guest physical
address to a host physical address. The guest physical address
corresponds to a guest domain identified by a guest domain identifier in
an input/output (I/O) transaction requested by an I/O device. A register
stores an invalidating domain identifier identifying an invalidating
domain and an indicator indicating invalidating an entry in the cached
entries having a tag.