Messages in this thread | | | Date | Fri, 10 Dec 2021 08:31:09 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 1/4] ioasid: Reserve a global PASID for in-kernel DMA |
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On Fri, Dec 10, 2021 at 09:06:24AM +0000, Jean-Philippe Brucker wrote: > On Thu, Dec 09, 2021 at 10:14:04AM -0800, Jacob Pan wrote: > > > This looks like we're just one step away from device drivers needing > > > multiple PASIDs for kernel DMA so I'm trying to figure out how to evolve > > > the API towards that. It's probably as simple as keeping a kernel IOASID > > > set at first, but then we'll probably want to optimize by having multiple > > > overlapping sets for each device driver (all separate from the SVA set). > > Sounds reasonable to start with a kernel set for in-kernel DMA once we need > > multiple ones. But I am not sure what *overlapping* sets mean here, could > > you explain? > > Given that each device uses a separate PASID table, we could allocate the > same set of PASID values for different device drivers. We just need to > make sure that those values are different from PASIDs allocated for user > SVA.
Why does user SVA need global values anyhow?
Jason
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