RE: [RFC] /dev/ioasid uAPI proposal

[Tian, Kevin]

> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Thursday, June 3, 2021 8:46 PM
> 
> On Thu, Jun 03, 2021 at 04:26:08PM +1000, David Gibson wrote:
> 
> > > There are global properties in the /dev/iommu FD, like what devices
> > > are part of it, that are important for group security operations. This
> > > becomes confused if it is split to many FDs.
> >
> > I'm still not seeing those.  I'm really not seeing any well-defined
> > meaning to devices being attached to the fd, but not to a particular
> > IOAS.
> 
> Kevin can you add a section on how group security would have to work
> to the RFC? This is the idea you can't attach a device to an IOASID
> unless all devices in the IOMMU group are joined to the /dev/iommu FD.
> 
> The basic statement is that userspace must present the entire group
> membership to /dev/iommu to prove that it has the security right to
> manipulate their DMA translation.
> 
> It is the device centric analog to what the group FD is doing for
> security.
> 

Yes, will do.

Thanks
Kevin