On Mon, Dec 09, 2019 at 12:13:40PM -0700, Logan Gunthorpe wrote: > This changes is pretty routine for most of the arches: x86_64, s390, arm64 > and powerpc simply need to thread the pgprot through to where the page tables > are setup. x86_32 unfortunately sets up the page tables at boot so > must use _set_memory_prot() to change their caching mode. ia64 and sh > don't appear to have an easy way to change the page tables so, for now > at least, we just return -EINVAL on such mappings and thus they will > not support P2PDMA memory until the work for this is done. ia64 and sh don't support ZONE_DEVICE mappings anyway as far as I know. This generally looks fine to me.