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See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam05 X-Stat-Signature: heajppn95otx8ow78y9k4cbjxsw74cj4 X-Rspam-User: X-Rspamd-Queue-Id: 20024180006 X-HE-Tag: 1761117040-450763 X-HE-Meta: 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 ziIGN4cz TixgLdzSaCipHWQOvd9Bmh706Fbpuz7RgqTGNBxFGKFfGPEFry3TPGrIGg189SptlsRGCYolHErehpI+ER6UCkRly2wrRTWMJeMggienGoU1N57za1gZ/LFm15kqRxem/PhSejYvXRxXpUdBcLHNcv+sVC7xXYJnJzFyvTvYw6mOu9YpUzy2AerSSpRhbjLDHC6DkqpU6s2fmY9h0lDcL6Xpw3RMBSzRdtZTf7Bejij60StkAdxohTtlmsgEjZ8LPhq15yPo2ZNCF+/HcXRoKkgtINZzBs0tjLGxyNRHMt84eaoAYSzYwsTna4hAGAokhCSM640HbMtv1tDDGDYF6WeFdKO0wNMwx/t4XbedLUPY2hGyY+fJ4rBFVzZ9MyRC8Zq79X0WWma6x30nwJQ81T2/TRXE5kstdqMDjzClBzuv+B0w97kiz1h63jccxBNGoKGC5qo1wmpzKTinFaiehJuR+19Bs8nq95Zfq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Oct 20, 2025 at 09:58:54AM -0300, Jason Gunthorpe wrote: > I explained it in detail in the message you are repling to. If > something is not clear can you please be more specific?? > > Is it the mmap in VFIO perhaps that is causing these questions? > > VFIO uses a PFNMAP VMA, so you can't pin_user_page() it. It uses > unmap_mapping_range() during its remove() path to get rid of the VMA > PTEs. This all needs to g• into the explanation. > Instead the DMABUF FD is used to pass the MMIO pages between VFIO and > another driver. DMABUF has a built in invalidation mechanism that VFIO > triggers before remove(). The invalidation removes access from the > other driver. > > This is different than NVMe which has no invalidation. NVMe does > unmap_mapping_range() on the VMA and waits for all the short lived > pgmap references to clear. We don't need anything like that because > DMABUF invalidation is synchronous. Please add documentation for this model to the source tree.