A system that includes a switched fabric hierarchy (e.g., a PCIe hierarchy) may realize efficient utilization of a shared I/O device (e.g., a network or storage switch) across multiple physically separate processing nodes (endpoints). For example, each processing node (endpoint) in a distributed processing system may be allocated a portion of the address map of a shared I/O device and may host a device driver for one of multiple virtual functions implemented on the shared device. Following enumeration and initialization of the hierarchy by the root complex, the endpoints may access the virtual functions directly (without intervention by the root complex). Data and interrupt traffic between endpoints and virtual functions may take place over peer-to-peer connections. Interrupt reception logic in each endpoint may receive and handle interrupts generated by the virtual functions. The root complex may host a device driver for a physical function on the shared device.