On 2021/6/2 1:33, Jason Gunthorpe wrote: > On Tue, Jun 01, 2021 at 08:30:35PM +0800, Lu Baolu wrote: > >> The drivers register per page table fault handlers to /dev/ioasid which >> will then register itself to iommu core to listen and route the per- >> device I/O page faults. > > I'm still confused why drivers need fault handlers at all? Essentially it is the userspace that needs the fault handlers, one case is to deliver the faults to the vIOMMU, and another case is to enable IOPF on the GPA address space for on-demand paging, it seems that both could be specified in/through the IOASID_ALLOC ioctl? Thanks, Shenming
