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Why has it taken until now for this to be >>> reported? :) commit 8ac268436e6d ("mm/gup: disallow FOLL_LONGTERM GUP-nonfast >>> writing to file-backed mappings") is from May 2023 :) >> The break didn't come from your changes, it came from commit 7e066cb9b71a ("KVM: >> SEV: Use long-term pin when registering encrypted memory regions"). I suggested >> falling back to a non-longterm pin, but David didn't like that idea :-) > Yes, a longterm pin is a longterm pin. > > If we don't write to the memory, why do we need a write pin? To make sure that > what we pin was actually unshared? > > Well, FOLL_LONGTERM does that nowadays. > > > ... so is maybe dropping the FOLL_WRITE sufficient? Yes, All that is correct. Sent a v2. Thank you! Pankaj