> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Tuesday, October 22, 2024 9:16 PM > > On Tue, Oct 22, 2024 at 04:59:07PM +0800, Baolu Lu wrote: > > > Is it feasible to make vIOMMU object more generic, rather than strictly > > tying it to nested translation? For example, a normal paging domain that > > translates gPAs to hPAs could also have a vIOMMU object associated with > > it. > > > > While we can only support vIOMMU object allocation uAPI for S2 paging > > domains in the context of this series, we could consider leaving the > > option open to associate a vIOMMU object with other normal paging > > domains that are not a nested parent? > > Why? The nested parent flavour of the domain is basically free to > create, what reason would be to not do that? > > If the HW doesn't support it, then does the HW really need/support a > VIOMMU? > Now it's agreed to build trusted I/O on top of this new vIOMMU object. format-wise probably it's free to assume that nested parent is supported on any new platform which will support trusted I/O. But I'm not sure all the conditions around allowing nested are same as for trusted I/O, e.g. for ARM nesting is allowed only for CANWBS/S2FWB. Are they always guaranteed in trusted I/O configuration? Baolu did raise a good open to confirm given it will be used beyond nesting. 😊
