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Howlett" , Oscar Salvador , Suren Baghdasaryan , Andrea Arcangeli References: <20251014231501.2301398-1-peterx@redhat.com> <20251014231501.2301398-2-peterx@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20251014231501.2301398-2-peterx@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: xEaS2mgPNT6PwNWqj0-w2LBqo1ROPAQZYmgauhFAZlQ_1760969910 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: d4audbgp9f5ymxa57jdxawrytkdrbkdr X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 9D84B1C0015 X-HE-Tag: 1760969913-856733 X-HE-Meta: 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 g/WvQuIi 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 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 15.10.25 01:14, Peter Xu wrote: > Currently, most of the userfaultfd features are implemented directly in the > core mm. It will invoke VMA specific functions whenever necessary. So far > it is fine because it almost only interacts with shmem and hugetlbfs. > > Introduce a generic userfaultfd API extension for vm_operations_struct, > so that any code that implements vm_operations_struct (including kernel > modules that can be compiled separately from the kernel core) can support > userfaults without modifying the core files. > > With this API applied, if a module wants to support userfaultfd, the > module should only need to properly define vm_uffd_ops and hook it to > vm_operations_struct, instead of changing anything in core mm. > > This API will not work for anonymous memory. Handling of userfault > operations for anonymous memory remains unchanged in core mm. > > Due to a security concern while reviewing older versions of this series > [1], uffd_copy() will be temprorarily removed. IOW, MISSING-capable memory > types can only be hard-coded and implemented in mm/. It would also affect > UFFDIO_COPY and UFFDIO_ZEROPAGE. Other functions should still be able to > be provided from vm_uffd_ops. > > Introduces the API only so that existing userfaultfd users can be moved > over without breaking them. > > [1] https://lore.kernel.org/all/20250627154655.2085903-1-peterx@redhat.com/ > > Signed-off-by: Peter Xu > --- Acked-by: David Hildenbrand -- Cheers David / dhildenb