On Wed, Feb 12, 2025 at 02:16:54PM +0000, Robin Murphy wrote: > On 2025-02-12 2:03 pm, Jason Gunthorpe wrote: > > On Wed, Feb 12, 2025 at 01:56:55PM +0000, Robin Murphy wrote: > > > On 2025-02-07 2:46 pm, Jason Gunthorpe wrote: > > > > virtio-iommu has a mode where the IDENTITY domain is actually a paging > > > > domain with an identity mapping covering some of the system address > > > > space manually created. > > > > > > > > To support this add a new domain_alloc_identity() op that accepts > > > > the struct device so that virtio can allocate and fully finalize a > > > > paging domain to return. > > > > > > Oh, I'd already managed to forget this idea - this could be convenient for > > > DART to implement per-instance identity domain support as well. > > > > If we are going to broaden this someday then I suggest the core code should > > implement it entirely buy asking the driver for a paging domain and > > then mapping all of system memory into it. There is nothing special > > here that needs to be in driver code. > > Sorry, that was just in terms of having a domain_alloc_identity() op that's > allowed to fail, being potentially neater than otherwise having to register > distinct per-instance ops with and without the static > identity_domain. Oh, I see, yes, that would be much better that the tricks drivers do with the default domain too. Jason
