On Fri, Jun 24, 2022 at 03:28:33PM -0300, Jason Gunthorpe wrote: > On Thu, Jun 23, 2022 at 01:00:27PM -0700, Nicolin Chen wrote: > > The domain->ops validation was added, as a precaution, for mixed-driver > > systems. > > > > Per Robin's remarks, > > * While bus_set_iommu() still exists, the core code prevents multiple > > drivers from registering, so we can't really run into a situation of > > having a mixed-driver system: > > https://lore.kernel.org/kvm/6e1280c5-4b22-ebb3-3912-6c72bc169982@xxxxxxx/ > > > > * And there's plenty more significant problems than this to fix; in future > > when many can be permitted, we will rely on the IOMMU core code to check > > the domain->ops: > > https://lore.kernel.org/kvm/6575de6d-94ba-c427-5b1e-967750ddff23@xxxxxxx/ > > > > So remove the check in VFIO for simplicity. > > As discussed we can't remove this check, multiple iommus on different > busses are allowed today and VFIO does not restrict its attempts to > attach a pre-existing domain to a single group or bus. > > Please go back to the original version with the ops check in the core > code. Robin convinced me, so never mind :) Jason
