Re: Plan for /dev/ioasid RFC v2

Jason Gunthorpe
2021-06-24T11:56:40Z

On Thu, Jun 24, 2021 at 02:29:29PM +1000, David Gibson wrote:

> But as I keep saying, some forms of grouping (and DMA aliasing as Alex
> mentioned) mean that changing the domain of one device can change the
> domain of another device, unavoidably. It may be rare with modern
> hardware, but we still can't ignore the case.
>
> Which means you can't DMA block until everything in the group is
> managed by a vfio-like driver.

We just need the same restriction as today, the group fd will attach a
domain under quite a wide range of conditions, and we can copy that.

IIRC is not a requirement today that every device in the group have a
vfio driver bound to it?

Jason