Messages in this thread | | | Date | Tue, 11 May 2021 13:35:21 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v4 1/2] iommu/sva: Tighten SVA bind API with explicit flags |
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On Tue, May 11, 2021 at 09:14:52AM -0700, Jacob Pan wrote:
> > Honestly, I'm not convinced we should have "kernel SVA" at all.. Why > > does IDXD use normal DMA on the RID for kernel controlled accesses? > > Using SVA simplifies the work submission, there is no need to do map/unmap. > Just bind PASID with init_mm, then submit work directly either with ENQCMDS > (supervisor version of ENQCMD) to a shared workqueue or put the supervisor > PASID in the descriptor for dedicated workqueue.
That is not OK, protable drivers in Linux have to sue dma map/unmap calls to manage cache coherence. PASID does not opt out of any of that.
I dislike this whole idea a lot. A single driver should not opt itself out of IOMMU based security "just because"
Jason
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