[PATCH 10/10] iommufd: Allow iommufd to supply /dev/vfio/vfio

[Jason Gunthorpe]

On Wed, Oct 26, 2022 at 03:31:33PM -0600, Alex Williamson wrote:
> On Tue, 25 Oct 2022 15:50:45 -0300
> Jason Gunthorpe <jgg at nvidia.com> wrote:
> 
> > If the VFIO container is compiled out, give a kconfig option for iommufd
> > to provide the miscdev node with the same name and permissions as vfio
> > uses.
> > 
> > The compatibility node supports the same ioctls as VFIO and automatically
> > enables the VFIO compatible pinned page accounting mode.
> 
> I think I'd like to see some sort of breadcrumb when /dev/vfio/vfio is
> provided by something other than the vfio container code.  If we intend
> to include this before P2P is resolved, that breadcrumb 

I don't belive I can get P2P done soon enough. I plan to do it after
this is merged. Right now these two series are taking all my time.

> (dmesg I'm guessing) might also list any known limitations of the
> compatibility to save time with debugging.  Thanks,

Yes, that makes sense.

Do you want a dmesg at module load time, on every open, or a sysfs
something? What seems like it would make it into a bug report?

Thanks,
Jason