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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c711d2847asm24465185a.34.2026.01.27.10.37.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jan 2026 10:37:02 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vknvx-00000009Cgi-2fGw; Tue, 27 Jan 2026 14:37:01 -0400 Date: Tue, 27 Jan 2026 14:37:01 -0400 From: Jason Gunthorpe To: Matthew Brost Cc: intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, leonro@nvidia.com, francois.dugast@intel.com, thomas.hellstrom@linux.intel.com, himal.prasad.ghimiray@intel.com Subject: Re: [RFC PATCH v2 0/3] Use new dma-map IOVA alloc, link, and sync API in GPU SVM and DRM pagemap Message-ID: <20260127183701.GI1641016@ziepe.ca> References: <20260123215907.1643088-1-matthew.brost@intel.com> <20260123224146.GB1641016@ziepe.ca> <20260124002610.GC1641016@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Jan 27, 2026 at 08:54:22AM -0800, Matthew Brost wrote: > That will likely work for dma-buf, let me see if I can convert our > dma-buf flows to use this helper. But it won't work for things like SVM, > so it would be desirable to figure out to have an API drivers can use to > iova alloc/link/sync/unlink/free for multi-device or just agree we trust > drivers enough to use the existing API. SVM should be driven with HMM and there is a helper in hmm_dma_map_pfn() for this. Yonatan posted a series to expand it to work with ZONE_DEVICE PRIVATE pages but it needs a refresh https://lore.kernel.org/linux-rdma/20250718115112.3881129-1-ymaman@nvidia.com/ If there are other cases it would be reasonable to discuss enhancing hmm_dma_map_pfn(). Jason