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Mon, 22 Sep 2025 10:51:22 -0700 (PDT) Received: from ziepe.ca ([130.41.10.202]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-77ee58e54c3sm2020597a34.2.2025.09.22.10.51.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Sep 2025 10:51:21 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1v0kh6-0000000AlpO-2Gtc; Mon, 22 Sep 2025 14:51:20 -0300 Date: Mon, 22 Sep 2025 14:51:20 -0300 From: Jason Gunthorpe To: Alex Mastro Cc: Mostafa Saleh , "Tian, Kevin" , Keith Busch , Alex Williamson , Bjorn Helgaas , David Reiss , Joerg Roedel , Leon Romanovsky , Li Zhe , Mahmoud Adam , Philipp Stanner , Robin Murphy , "Kasireddy, Vivek" , Will Deacon , Yunxiang Li , "linux-kernel@vger.kernel.org" , "iommu@lists.linux.dev" , "kvm@vger.kernel.org" Subject: Re: [TECH TOPIC] vfio, iommufd: Enabling user space drivers to vend more granular access to client processes Message-ID: <20250922175120.GA2547959@ziepe.ca> References: <20250922174630.3123741-1-amastro@fb.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250922174630.3123741-1-amastro@fb.com> On Mon, Sep 22, 2025 at 10:46:23AM -0700, Alex Mastro wrote: > Following a dma_buf_ops.mmap, I suppose that revocation would mean: I'd investigate adding some ioctl to the dmabuf fd to permanently revoke it. The zapping/etc already has to be done just to get mmap in the first place. The vending process would retain a FD on the dmabuf and when it is time to revoke it then it can call the ioctl directly on the fd to revoke. Jason