On 17 July 2017 at 19:58, Dr. David Alan Gilbert <dgilb...@redhat.com> wrote: > * Edgar E. Iglesias (edgar.igles...@gmail.com) wrote: >> Is there a way we can prevent migration of the RAMBlock? > > Not yet, I think we'd have to: > a) Add a flag to the RAMBlock > b) Set it/clear it on registration > c) Have a RAMBLOCK_FOREACH_MIGRATABLE macro > d) Replace all of the RAMBLOCK_FOREACH (and the couple of hand coded > cases) with the RAMBLOCK_FOREACH_MIGRATABLE > e) Worry about the corner cases! > > I've got a few worries about what happens when the kernel tries to > do dirty yncing - I'm not sure if we have to change anything on that > interface to skip those RAMBlocks.
OK, so what should we do for 2.10 ? We could: * implement the changes you suggest above, and mark only vmstate_register_ram'd blocks as migratable (would probably need to fix some places which buggily don't call vmstate_register_ram) * implement the changes above, but special case mmio-interface so only its ramblock is marked unmigratable * postpone the changes above until 2.11, and for 2.10 register a migration-blocker in mmio-interface so that we at least give the user a useful error rather than having it fail obscurely on vmload (and release note this) (Or something else?) I do think we definitely need to fix this for 2.11 at latest. thanks -- PMM
