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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On 9/22/26 01:23, James Houghton wrote: >> James, how are you feeling about an early morning PUCK in the near future? > No problems here; the 23rd is fine. The only day I can't do in the > near-ish future is Oct 14. Thanks! Great. To sum up what I would like to understand, this is it: 1) the overlap between memory protection attributes and kvm-userfault. It seems to me that they are almost the same, but I may be wrong. In particular, they are almost the same in that they are both stop-and-retry interfaces, unlike userfaultfd which hides the stop-and-retry behind a page fault and a stopped thread. 2) what strategy you have implemented, or you have in mind, to handle stop-and-retry for code that does many consecutive memory accesses. The main one is nested vmentry/vmexit. I have here some mostly untested code that splits them into prepare/commit/cancel phases, but I haven't dared posting it. (Secondarily, we have a TDX-sized dependency between planes, memory attributes, VBS, and kvm-userfault. That is probably something worth discussing too, sooner or later). Paolo