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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 21ADE140011 X-Stat-Signature: 8xbb5odhnk6my7up5917gcfhzny31gif X-HE-Tag: 1751621662-951024 X-HE-Meta: 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 M8fNyPV2 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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 03.07.25 19:48, Mike Rapoport wrote: > On Wed, Jul 02, 2025 at 03:46:57PM -0400, Peter Xu wrote: >> On Wed, Jul 02, 2025 at 08:39:32PM +0300, Mike Rapoport wrote: >> >> [...] >> >>>> The main target of this change is the implementation of UFFD for >>>> KVM/guest_memfd (examples: [1], [2]) to avoid bringing KVM-specific code >>>> into the mm codebase. We usually mean KVM by the "drivers" in this context, >>>> and it is already somewhat "knowledgeable" of the mm. I don't think there >>>> are existing use cases for other drivers to implement this at the moment. >>>> >>>> Although I can't see new exports in this series, there is now a way to limit >>>> exports to particular modules [3]. Would it help if we only do it for KVM >>>> initially (if/when actually needed)? >>> >>> There were talks about pulling out guest_memfd core into mm, but I don't >>> remember patches about it. If parts of guest_memfd were already in mm/ that >>> would make easier to export uffd ops to it. >> >> Do we have a link to such discussion? I'm also curious whether that idea >> was acknowledged by KVM maintainers. > > AFAIR it was discussed at one of David's guest_memfd calls While it was discussed in the call a couple of times in different context (guest_memfd as a library / guest_memfd shim), I think we already discussed it back at LPC last year. One of the main reasons for doing that is supporting guest_memfd in other hypervisors -- the gunyah hypervisor in the kernel wants to make use of it as well. -- Cheers, David / dhildenb