On 29 July 2015 at 13:05, Igor Mammedov <imamm...@redhat.com> wrote: > Now imagine that guest was started on host with 'old' layout and then has been > migrated to a host with 'new' layout. Stability of layout matters, that's why > we support versioned machine types and compat nightmare even if basic machine > is the same, the same applies to ARM's virt machine.
Note that we don't support versioned machines or cross-version migration on ARM *yet*. We will at some point but I am putting this off for as long as I can exactly because it makes it very painful to make changes to QEMU. (Roughly, I plan to avoid cross-version migration until the point where somebody comes along and says (a) they absolutely need this and (b) they are prepared to support it in terms of the testing effort etc. I don't think we have really ironed out all the bugs in same-version migration on ARM yet...) thanks -- PMM
