* Igor Mammedov (imamm...@redhat.com) wrote: > On Tue, 30 Jul 2019 15:34:54 +0200 > Paolo Bonzini <pbonz...@redhat.com> wrote: > > > On 30/07/19 15:25, Igor Mammedov wrote: > > > I'd guess you've meant RAMBlocks instead of memory regions, if that's it > > > then yes, every alias pointing to RAM backed memory region will have > > > RAMBlock that's points to aliased part of aliased memory region. > > > > The question is just, does it break migration from old QEMU to new QEMU > > on x86 (which has plenty of RAM-backed aliases)? If not, explain that > > in the commit message or in a code comment. > > pc/q35 old<->new new<->old ping pong tests worked fine (qemu with default > devices). > > My understanding was that one needs to call vmstate_register_ram() > to make memory region migratable, which marks specific RAMBlock > as migratable. So just assigning new RAMBlock to mr->ram_block shouldn't > affect migration, unless vmstate_register_ram() is called on alias.
You're right; that's actually relatively new and I forget about it. From Cedric's b895de50271 in 3.0, before that we migrated every RAMBlock. So yes, I think you should be OK. Dave > I'll add it to commit message. > > > > > Paolo > > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
