On Tue, Nov 03, 2020 at 03:03:18PM +0100, joro@xxxxxxxxxx wrote: > On Tue, Nov 03, 2020 at 09:23:35AM -0400, Jason Gunthorpe wrote: > > Userspace needs fine grained control over the composition of the page > > table behind the PASID, 1:1 with the mm_struct is only one use case. > > VFIO already offers an interface for that. It shouldn't be too > complicated to expand that for PASID-bound page-tables. > > > Userspace needs to be able to handle IOMMU faults, apparently > > Could be implemented by a fault-fd handed out by VFIO. The point is that other places beyond VFIO need this > I really don't think that user-space should have to deal with details > like PASIDs or other IOMMU internals, unless absolutly necessary. This > is an OS we work on, and the idea behind an OS is to abstract the > hardware away. Sure, but sometimes it is necessary, and in those cases the answer can't be "rewrite a SVA driver to use vfio" Jason
