On Mon, Apr 06, 2026 at 07:05:21PM -0300, Jason Gunthorpe wrote: > On Mon, Apr 06, 2026 at 05:22:06PM -0400, Gregory Price wrote: > > On Sat, Apr 04, 2026 at 12:36:53PM -0700, Dan Williams wrote: > > > Jason Gunthorpe wrote: > > I would expect this to happen via the request_resource mechanism, if > MM is using the CXL range it should be locked in the resource tree and > vfio should request it and then fail during the initial startup > phases. > > > I need to read up a little bit on this area, but i don't see the "needs > > to be mmap'able in a cache coherent way" to be an argument for one > > particular method or another (hotplug, private node, memremap, etc). > > It is speaking to what VFIO has to do. It is the exclusive owner of > the physical range, it does not have struct pages, it must be cachable > for VFIO and KVM to work - not alot of choices here. Turn the > phys_addr_t's into large cachable special PTEs inside a VMA. >
Right - the observation here is essentially "if you need struct page and need to get fancy with them...". But if you just need to plonk a region into one set of page tables and move on - then this is fine and arguable preferable. ~Gregory
