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[47.54.130.67]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9153244de53sm312617585a.8.2026.05.29.13.11.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 May 2026 13:11:31 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wT3YI-00000000q8h-45Mx; Fri, 29 May 2026 17:11:30 -0300 Date: Fri, 29 May 2026 17:11:30 -0300 From: Jason Gunthorpe To: Christian =?utf-8?B?S8O2bmln?= Cc: Zhiping Zhang , Alex Williamson , Leon Romanovsky , Sumit Semwal , Bjorn Helgaas , kvm@vger.kernel.org, linux-rdma@vger.kernel.org, linux-pci@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Keith Busch , Yochai Cohen , Yishai Hadas , Linus Torvalds Subject: Re: [PATCH v5 0/4] vfio/dma-buf: add TPH support for peer-to-peer access Message-ID: <20260529201130.GU2487554@ziepe.ca> References: <20260526144401.1485788-1-zhipingz@meta.com> <20260527121438.GJ2487554@ziepe.ca> <20260527123634.GK2487554@ziepe.ca> <71302a7a-6b9f-40da-af81-b1862dbd637a@amd.com> <8d9bb0b7-182d-4930-b683-d5d24da6b2ab@amd.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8d9bb0b7-182d-4930-b683-d5d24da6b2ab@amd.com> On Fri, May 29, 2026 at 09:36:00AM +0200, Christian König wrote: > On 5/29/26 08:34, Zhiping Zhang wrote: > ... > > There's no in-tree vendor PF driver > > Well I have to admit it's a bit on the edge but this sentence is a > show stopper. I think he means the device is not SRIOV. vfio-pci is the in-kernel PF driver. > DMA-buf is an in kernel interface for buffer sharing between drivers > and any change to it needs an in kernel driver as justification for > the added complexity. vfio is the in-kernel driver, this series fully shows the in-kernel API using vfio as the exporter and mlx5 as the importer. It certainly meets the standard required to show in-tree users. > When you have a complete open source driver stack which utilizes > VFIO passthrough as the interface to communicate with the kernel > drivers then we can eventually talk about that. That decision is not up to dmabuf - what VFIO subsystem requires to accept a new UAPI is up to the VFIO maintainers. DRM and VFIO have very different views on what is required to merge a new uAPI. Jason