1. A computer program product for facilitating memory access, the computer program product comprising: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: based on executing, by a processor, a Modify PCI Function Controls (MPFC) instruction that specifies a handle for locating an adapter and a format field for explicitly indicating a selected translation format of a plurality of available translation formats to translate input/output addresses provided by the adapter to direct memory access (DMA) addresses usable in accessing system memory, setting a translation format, associated by way of the handle with the adapter, to the selected translation format indicated in the format field of the MPFC instruction, the selected translation format being pre-registered for the adapter, and wherein the plurality of available translation formats includes one or more of the following formats: a selected central processing unit dynamic address translation (CPU DAT) compatible format, a chosen input/output (I/O) extended address translation format which uses one or more extended address translation tables, a bypass format in which address translation is bypassed, or a no fetch format in which no address translation tables are fetched; based on receiving a request from the adapter, obtaining at runtime an indication of the selected translation format to be used in providing a direct memory access address usable in accessing system memory, said selected translation format being set based on execution of the MPFC instruction, the request having an initial address to be used in providing the direct memory access address usable in accessing system memory; determining the direct memory access address usable in accessing system memory based on the obtained translation format and the initial address, the initial address generated by the adapter; and storing or fetching adapter data at the DMA address.