Abstract: A computer system includes a shared I/O device including functions providing access to device local memory space, and a plurality of roots coupled to the shared I/O device via a switch fabric. A first root assigns a first address in a first root memory space to a first function. A second root assigns a second address in a second root memory space to a second function. The switch fabric maps the first root memory space to a first portion of device local memory space and the second root memory space to a second portion of device local memory space. Subsequently, the switch receives a data transaction request from the first root targeted to the first address, translates the first address to a corresponding location in the first portion of the device local memory space based on the mapping, and routes the data transaction request to the I/O device.