A method for processing an instruction by a processor operationally connected to one or more buses comprises determining the instruction is to access an address of an address space that maps a memory and comprises a range of MMIO addresses. The method determines the address being accessed is within the range of MMIO addresses and generates, based on the determination, a first translation of the address being accessed to a bus identifier identifying one of the buses and a bus address of a bus address space. The bus address resulting from the translation is assigned to a device accessible via the identified bus. The method generates an entry in a translation lookaside buffer. A request directed to the device is sent via the identified bus to the bus address resulting from the translation.