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b=YyRSh1AY/kLvcXE2EMoEKJ23nXytxgWZvz58cGiz5RT3NrBZHUXzJn24OjryqiwRV laegr90sLsUyToXcAMLFgdV13xazA5Ncou0kjL3VIDucIF2qqlGwPO6QsYUKE8GLas YaI8zgX/SIKLti5MMpwGGmiylScsZ/4GQYOFIj415F/v77L9Gxj5i/lxcEmpk76X7D 7TtvZ8Cunn4C9kkzpwIVBV/h5d9UEyqDz3Z303MIBDZG+1ndgTNRQfHUfeIHfoeu5p v9uj0lkcpzBVG2ZHgnWcdaGyr2/iF56Rp84Ikzxkm3wOIy0JB/kuoa8VtdfGoQ/0zc c/9iimlBG4GIA== From: Pratyush Yadav To: David Rientjes Cc: Alexander Graf , Anthony Yznaga , Dave Hansen , David Hildenbrand , Frank van der Linden , James Gowans , Jason Gunthorpe , Junaid Shahid , Matthew Wilcox , Mike Rapoport , Pankaj Gupta , Pasha Tatashin , Pratyush Yadav , Vipin Sharma , Vishal Annapurve , "Woodhouse, David" , linux-mm@kvack.org, kexec@lists.infradead.org Subject: Re: [Hypervisor Live Update] Notes from February 24, 2025 In-Reply-To: <7154b857-01cf-a8c6-ea02-51d095bafabf@google.com> References: <7154b857-01cf-a8c6-ea02-51d095bafabf@google.com> Date: Fri, 07 Mar 2025 01:09:45 +0000 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: D473080005 X-Stat-Signature: tgau3zws4cfozoedszi5ourbo69jb47k X-HE-Tag: 1741309790-947975 X-HE-Meta: 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 s8tYmOdu L6ePzgxpWftALR1Xa2sb6Fx05dqwpqvpO6PTsUYTcc92bfRZuDE6wDPJ6hTBQjCd4qe6MD8Cet8ZmxHEnD+5tL4r2vwk8Jz5cuSXEO4UZPJvq+QvLszV4c/4em4gwO1ALoR3ipuL9MMrLqrg4oXzHmRFZSu6HbuAZ0yICYhW78ZJltZJSxWLWwS2BqstkizoXACM6rgFgTaWQyEmLzQYDl/GLgbgiIzAjCz4TUX49YEY4OP18mjN9oenUtRRjzkUHaF+EHo/8B6LaxtAuFE2zrktP1qSQCj9PlH+J X-Bogosity: Ham, tests=bogofilter, spamicity=0.070309, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi all, On Sun, Mar 02 2025, David Rientjes wrote: > Hi everybody, > > Here are the notes from the last Hypervisor Live Update call that happened > on Monday, February 24. Thanks for everybody who was involved! > [...] > > Pratyush took the AI to look at implementation on memfd. Mike took the > AI to look at memory reservation. > > ----->o----- > I pivoted the discussion toward fdbox which ended up never being posted > upstream. Pratyush provided the link to the most recent code: > https://github.com/agraf/linux-2.6/blob/kvm-kho-gmem-test/drivers/misc/fdbox.c > This work likely would need to be picked up to pursue upstream because > the current code has several TODO's. (A struct miscdevice was called out > as curious.) > > It was noted that it would be difficult to support memfd without > something like fdbox, so whether the fdbox code itself were upstreamed or > it becomes more generic from the work on memfd, the base support would > need to be provided somehow. > > Mike and Jason suggested designing fdbox and then starting to use it for > memfd. This would need to be aligned by stakeholders, including the UAPI > for fdbox. Pratyush will be looking into fdbox or inventing something > similar while working on memfd. > > We need to propose the fdbox design and UAPI. As promised, I have taken the last couple weeks in coming up with a basic FDBox design, along with having memfd use it (currently via shmem, since I am more familiar with that than with hugetlbfs). The patches can be found at [0]. I am travelling next week so I am not sure if I will be able to attend the next session. If I do, I would like to talk more about the patches and FDBox if time permits. Anyway, looking forward to getting some feedback on the patches :-) [0] https://lore.kernel.org/linux-mm/20250307005830.65293-1-ptyadav@amazon.de/T/#u [...] -- Regards, Pratyush Yadav