Public bug reported: Further testing has found more s390x migration issues. Migration from a former release to the new stack (works) and back (fails). Lets pick the closest release Eoan as an example.
A guest started on Eoan (libvirt 5.4 qemu 4.0) migrates to Focal (libvirt 6.0 / qemu 4.2) fine. But on the way back it breaks with: error: internal error: qemu unexpectedly closed the monitor: 2020-01-29T10:41:04.977115Z qemu-system-s390x: can't apply global z13-base-s390x-cpu.apqi=on: Property '.apqi' not found As you know this is a typical scenario on upgrades in case you want to e.g. roll back this issue would break your case. apqi was added in 4.1 - so that all fits together. But my expectation from recent years on x86 would have been that on the forward migration the attribute isn't added and then due to that it could properly migrate backward again. To be clear, all this is part of the cpu modelling. It only triggers if that guest is started with some host-model set. If I start with host-passthrough then (as expected) no checks are in palce and it migrates both ways. Please let me know if for you (=for IBM) this is a "oh crap that needs to be fixed" or a "well that is what it is" severity bug? ** Affects: libvirt (Ubuntu) Importance: Undecided Status: New ** Affects: qemu (Ubuntu) Importance: Undecided Status: New ** Also affects: qemu (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1861299 Title: s390x: migration to 4.2 makes it unable to migrate back to 4.0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1861299/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs