On Fri, Oct 25, 2024 at 04:58:33PM +1100, Alexey Kardashevskiy wrote: > > > > > Is there any real example of a .vdevice_alloc hook, besides the > > > > > selftests? It is not in iommufd_viommu_p2-v4-with-rmr, hence the > > > > > question. I am trying to sketch something with this new machinery and > > > > > less guessing would be nice. Thanks, > > > > > > > > No, I am actually dropping that one, and moving the vdevice struct > > > > to the private header, as there seems to be no use case: > > > > > > Why keep it then? > > > > We need that structure to store per-vIOMMU virtual ID. Hiding it > > in the core only means we need to provide another vIOMMU APIs for > > drivers to look up the ID, v.s. exposing it for drivers to access > > directly. > > Sorry I lost you here. If we need it, then there should be an example of > .vdevice_alloc() somewhere but you say they is not one. How do you test > this, with just selftests? :) Thanks, A vDEVICE object will be core-allocated and core-managed, while the vdevice_alloc is for driver-allocated purpose for which there is no use case (at least with this series). You can check the vdev ioctl in this version that has two pathways to allocate a vDEVICE object. A vdev_id is used to index viommu's xarray for a driver to convert the id to a dev pointer via a vIOMMU API. Dropping .vdevice_alloc just means the driver only lost its direct access. Nicolin
