On Oct 3, 2022, at 4:20 PM, Nadav Amit <nadav.amit@xxxxxxxxx> wrote: > On Oct 3, 2022, at 4:17 PM, Nadav Amit <nadav.amit@xxxxxxxxx> wrote: > >> On Oct 3, 2022, at 3:28 PM, Edgecombe, Rick P <rick.p.edgecombe@xxxxxxxxx> wrote: >> >>> On Mon, 2022-10-03 at 11:11 -0700, Nadav Amit wrote: >>>> Did you have a look at ptep_set_access_flags() and friends and >>>> checked they >>>> do not need to be changed too? >>> >>> ptep_set_access_flags() doesn't actually set any additional dirty bits >>> on x86, so I think it's ok. >> >> Are you sure about that? (lost my confidence today so I am hesitant). >> >> Looking on insert_pfn(), I see: >> >> entry = maybe_mkwrite(pte_mkdirty(entry), vma); >> if (ptep_set_access_flags(vma, addr, pte, entry, 1)) ... >> >> This appears to set the dirty bit while potentially leaving the write-bit >> clear. This is the scenario you want to avoid, no? > > No. I am not paying attention. Ignore. Sorry for the spam. Just this “dirty” argument is confusing. This indeed seems like a flow that can set the dirty bit. I think.
