On Tue, Oct 15, 2024 at 04:37:25PM +0100, Robin Murphy wrote: > On 2024-10-15 4:31 pm, Jason Gunthorpe wrote: > > On Tue, Oct 15, 2024 at 04:13:13PM +0100, Robin Murphy wrote: > > > On 2024-10-15 1:47 pm, Jason Gunthorpe wrote: > > > > On Tue, Oct 15, 2024 at 08:13:28AM +0000, Pranjal Shrivastava wrote: > > > > > > > > > Umm.. this was specific for rmr not a generic thing. I'd suggest to > > > > > avoid meddling with the STEs directly for acheiving bypass. Playing > > > > > with the iommu domain type could be neater. Perhaps, modify the > > > > > ops->def_domain_type to return an appropriate domain? > > > > > > > > Yeah, that is the expected way, to force the def_domain_type to > > > > IDENTITY and refuse to attach a PAGING/BLOCKED domain. > > > > > > There is no domain, this is bypassing an arbitrary StreamID not associated > > > with any device. > > > > If the stream ID is going to flow traffic shouldn't it have a DT node > > for it? Something must be driving the DMA on this SID, and the kernel > > does need to know what that is in some way, even for basic security > > things like making sure VFIO doesn't get a hold of it :\ > > Exactly, hence this RFC is definitely not the right approach. Agreed. I assumed the bypass was needed for a registered SID. > > Thanks, > Robin. Thanks, Pranjal
