On Mon, Nov 21, 2016 at 01:08:56PM +1100, Balbir Singh wrote: > > > On 19/11/16 05:18, Jérôme Glisse wrote: > > It does not need much, just skip populating kernel linear mapping > > for range of un-addressable device memory (it is pick so that there > > is no physical memory resource overlapping it). All the logic is in > > share mm code. > > > > Only support x86-64 as this feature doesn't make much sense with > > constrained virtual address space of 32bits architecture. > > > > Is there a reason this would not work on powerpc64 for example? > Could you document the limitations -- testing/APIs/missing features? It should be straight forward for powerpc64, i haven't done it but i certainly can try to get access to some powerpc64 and add support for it. The only thing to do is to avoid creating kernel linear mapping for the un-addressable memory (just for safety reasons we do not want any read/ write to invalid physical address). Cheers, Jérôme -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>