US Patent 10120832 Direct access to local memory in a PCI-E device

A method includes communicating between at least first and second devices over a bus in accordance with a bus address space, including providing direct access over the bus to a local address space of the first device by mapping at least some of the addresses of the local address space to the bus address space. In response to indicating, by the first device or the second device, that the second device requires to access a local address in the local address space that is not currently mapped to the bus address space, the local address is mapped to the bus address space, and the local address is accessed directly, by the second device, using the mapping.