On Thu, Jun 24, 2021 at 02:37:31PM +1000, David Gibson wrote: > On Thu, Jun 17, 2021 at 08:04:38PM -0300, Jason Gunthorpe wrote: > > On Thu, Jun 17, 2021 at 03:02:33PM +1000, David Gibson wrote: > > > > > In other words, do we really have use cases where we need to identify > > > different devices IDs, even though we know they're not isolated. > > > > I think when PASID is added in and all the complexity that brings, it > > does become more important, yes. > > > > At the minimum we should scope the complexity. > > > > I'm not convinced it is so complicated, really it is just a single bit > > of information toward userspace: 'all devices in this group must use > > the same IOASID' > > Um.. no? You could have devA and devB sharing a RID, but then also > sharing a group but not a RID with devC because of different isolation > issues. So you now have (at least) two levels of group structure to > expose somehow. Why? I don't need to micro optimize for broken systems. a/b/c can be in the same group and the group can have the bit set. It is no worse than what we have today. Jason
