* Юрий Котов (yury-ko...@yandex-team.ru) wrote: > Ping Is this fixed by Catherine Ho's patch series?
Dave > 21.03.2019, 19:27, "Yury Kotov" <yury-ko...@yandex-team.ru>: > > Hi, > > > > 19.03.2019, 14:52, "Dr. David Alan Gilbert" <dgilb...@redhat.com>: > >> * Peter Maydell (peter.mayd...@linaro.org) wrote: > >>> On Tue, 19 Mar 2019 at 11:03, Dr. David Alan Gilbert > >>> <dgilb...@redhat.com> wrote: > >>> > > >>> > * Peter Maydell (peter.mayd...@linaro.org) wrote: > >>> > > I didn't think migration distinguished between "main memory" > >>> > > and any other kind of RAMBlock-backed memory ? > >>> > > >>> > In Yury's case there's a distinction between RAMBlock's that are > >>> mapped > >>> > with RAM_SHARED (which normally ends up as MAP_SHARED) and all others. > >>> > You can set that for main memory by using -numa to specify a memdev > >>> > that's backed by a file and has the share=on property. > >>> > > >>> > On x86 the ROMs end up as separate RAMBlock's that aren't affected > >>> > by that -numa/share=on - so they don't fight Yury's trick. > >>> > >>> You can use the generic loader on x86 to load an ELF file > >>> into RAM if you want, which would I think also trigger this. > >> > >> OK, although that doesn't worry me too much - since in the majority > >> of cases Yury's trick still works well. > >> > >> I wonder if there's a way to make Yury's code to detect these cases > >> and not allow the feature; the best thing for the moment would seem to > >> be to skip the aarch test that uses elf loading. > > > > Currently, I've no idea how to detect such cases, but there is an ability to > > detect memory corruption. I want to update the RFC patch to let user to map > > some > > memory regions as readonly until incoming migration start. > > > > E.g. > > 1) If x-ignore-shared is enabled in command line or memory region is marked > > (something like ',readonly=on'), > > 2) Memory region is shared (,share=on), > > 3) And qemu is started with '-incoming' option > > > > Then map such regions as readonly until incoming migration finished. > > Thus, the patch will be able to detect memory corruption and will not affect > > normal cases. > > > > How do you think, is it needed? > > > > I already have a cleaner version of the RFC patch, but I'm not sure about > > 1). > > Which way is better: enable capability in command line, add a new option for > > memory-backend or something else. > > > >> Dave > >> > >>> thanks > >>> -- PMM > >> -- > >> Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > > > > Regards, > > Yury -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
