Re: [RFC] /dev/ioasid uAPI proposal

[Jason Gunthorpe]

On Tue, Jun 01, 2021 at 02:07:05PM +0800, Jason Wang wrote:

> For the case of 1M, I would like to know what's the use case for a single
> process to handle 1M+ address spaces?

For some scenarios every guest PASID will require a IOASID ID # so
there is a large enough demand that FDs alone are not a good fit.

Further there are global container wide properties that are hard to
carry over to a multi-FD model, like the attachment of devices to the
container at the startup.

> > So this RFC treats fd as a container of address spaces which is each
> > tagged by an IOASID.
> 
> If the container and address space is 1:1 then the container seems useless.

The examples at the bottom of the document show multiple IOASIDs in
the container for a parent/child type relationship

Jason