On Mon, Oct 18, 2021 at 02:50:54PM +1100, David Gibson wrote: > Hrm... which makes me think... if we allow this for the common > kernel-managed case, do we even need to have capcity in the high-level > interface for reporting IO holes? If the kernel can choose a non-zero > base, it could just choose on x86 to place it's advertised window > above the IO hole. If the high level interface is like dma_map() then, no it doesn't need the ability to report holes. Kernel would find and return the IOVA from dma_map not accept it in. Since dma_map is a well proven model I'm inclined to model the simplied interface after it.. That said, if we have some ioctl 'query iova ranges' I would expect it to work on an IOAS created by the simplified interface too. Jason
