On Wed, May 09, 2018 at 04:30:32PM +0000, Stephen Bates wrote: > Hi Jerome > > > Now inside that page table you can point GPU virtual address > > to use GPU memory or use system memory. Those system memory entry can > > also be mark as ATS against a given PASID. > > Thanks. This all makes sense. > > But do you have examples of this in a kernel driver (if so can you point me too it) or is this all done via user-space? Based on my grepping of the kernel code I see zero EP drivers using in-kernel ATS functionality right now... > As it is tie to PASID this is done using IOMMU so looks for caller of amd_iommu_bind_pasid() or intel_svm_bind_mm() in GPU the existing user is the AMD GPU driver see: drivers/gpu/drm/amd/ drivers/gpu/drm/amd/amdkfd/ drivers/gpu/drm/amd/amdgpu/ Lot of codes there. The GPU code details do not really matter for this discussions thought. You do not need to do much to use PASID. Cheers, Jérôme
