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Mon, 1 Jun 2026 10:04:00 +0000 Message-ID: <072c6d92-0481-4f77-b878-e94a9786d16a@amd.com> Date: Mon, 1 Jun 2026 12:03:53 +0200 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 0/4] vfio/dma-buf: add TPH support for peer-to-peer access To: Keith Busch Cc: Zhiping Zhang , Jason Gunthorpe , 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, Yochai Cohen , Yishai Hadas , Linus Torvalds 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> Content-Language: en-US From: =?UTF-8?Q?Christian_K=C3=B6nig?= In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: FR2P281CA0142.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:98::8) To PH7PR12MB5685.namprd12.prod.outlook.com (2603:10b6:510:13c::22) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5685:EE_|SA0PR12MB7462:EE_ X-MS-Office365-Filtering-Correlation-Id: fe418be1-7ee4-46cc-d799-08debfc51a55 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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I see you had concerns about even that, but still Acked > under the same model that's propsed in this series: > > https://lore.kernel.org/linux-pci/57b8876f-1399-4e4d-a44b-1177787aa17d@amd.com/ Well that wasn't driver to driver API but just some helpers which we didn't know where else to but. This here is an addition to the inter driver API which as far as I can see is currently not beneficial to anybody else. > So with vfio-pci and mlx5 both in-tree dmabuf users, implementing and > consuming the callback, does this not satisfy the requirement? The > userspace-driven semantics are inherent to VFIO's design. I don't see > what additional value open sourcing the user-side provides for the > kernel-side review process. Well upstreaming something into Linus tree only makes sense if others can use it. And as far as I can see without all components available this is not the case. Regards, Christian.