On Wed, Oct 17, 2018 at 03:21:43PM +0100, Jean-Philippe Brucker wrote: > Hi Jordan, > > On 12/10/2018 15:32, Jordan Crouse wrote: > > On Thu, Sep 20, 2018 at 06:00:46PM +0100, Jean-Philippe Brucker wrote: > >> Provide an API for allocating PASIDs and populating them manually. To ease > >> cleanup and factor allocation code, reuse the io_mm structure for private > >> PASID. Private io_mm has a NULL mm_struct pointer, and cannot be bound to > >> multiple devices. The mm_alloc() IOMMU op must now check if the mm > >> argument is NULL, in which case it should allocate io_pgtables instead of > >> binding to an mm. > >> > >> Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx> > >> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx> > >> --- > >> Sadly this probably won't be the final thing. The API in this patch is > >> used like this: > >> > >> iommu_sva_alloc_pasid(dev, &io_mm) -> PASID > >> iommu_sva_map(io_mm, ...) > >> iommu_sva_unmap(io_mm, ...) > >> iommu_sva_free_pasid(dev, io_mm) > >> > >> The proposed API for auxiliary domains is in an early stage but might > >> replace this patch and could be used like this: > >> > >> iommu_enable_aux_domain(dev) > >> d = iommu_domain_alloc() > >> iommu_attach_aux(dev, d) > >> iommu_aux_id(d) -> PASID > >> iommu_map(d, ...) > >> iommu_unmap(d, ...) > >> iommu_detach_aux(dev, d) > >> iommu_domain_free(d) > >> > >> The advantage being that the driver doesn't have to use a special > >> version of map/unmap/etc. > > > > Hi Jean-Phillippe - > > > > Have you thought about this any more? I want to send out a > > refresh for the per-context pagetables for arm-smmu so if we want to change > > the underlying assumptions this would be a great time. > > > > For my part I'm okay with either model. In fact the second one is closer > > to the original implementation that I sent out so I have a clear development > > path in mind for either option depending on what the community decides. > > We'll probably go with the second model. I'm trying to make the latest > version work with SMMUv3 > (https://lwn.net/ml/linux-kernel/20181012051632.26064-1-baolu.lu@xxxxxxxxxxxxxxx/) > and I'd like to send an RFC soon Okay. When you do, I'll try to add the v2 code and make it work with the Adreno GPU. Jordan -- The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
