Abstract: An apparatus and method are provided that enable I/O devices to be shared among multiple operating system domains. The apparatus has a first plurality of I/O ports, a second I/O port, and core logic. The first plurality of I/O ports is coupled to a plurality of operating system domains (OSDs) through a load-store fabric, each routing transactions between the plurality of OSDs and the switching apparatus. The second I/O port is coupled to a first shared input/output endpoint. The first shared input/output endpoint requests/completes the transactions for each of the plurality of OSDs. The core logic is coupled to the first plurality of I/O ports and the second I/O port. The core logic routes the transactions between the first plurality of I/O ports and the second I/O port. The core logic designates a corresponding one of the plurality of OSDs according to a variant of a protocol, where the protocol provides for routing of the transactions only for a single OSD.