Public bug reported: We have several thousands of virtual machines with pc-i440fx-wily machine type. Hypervisors run on ubuntu 16.04 and ubuntu 18.04.
We have several problems when we try to migrate those machines to hypervisors with ubuntu 20.04. * linux guests migrate OK, but for some weird reason windows guests (with the same XML domain definition) do not. We have the following error: --- qemu-system-x86_64: Features 0x8000002 unsupported. Allowed features: 0x71000002 qemu-system-x86_64: Failed to load virtio-console:virtio qemu-system-x86_64: error while loading state for instance 0x0 of device '0000:00:04.0/virtio-console --- I tried to investigate this issue and discovered following things: - missing feature is VIRTIO_F_ANY_LAYOUT for some of virtio devices - on xenial and bionic VIRTIO_F_ANY_LAYOUT is enabled for pc-i440fx-wily guests, observe: --- # virsh qemu-monitor-command some-guest --hmp info qtree | grep any_layout any_layout = true any_layout = true any_layout = false any_layout = true --- - on focal it is disabled --- # virsh qemu-monitor-command some-guest2 --hmp info qtree | grep any_layout any_layout = false any_layout = true any_layout = false any_layout = false --- I tried (helplessly) to compare source code for bionic and focal branches of qemu. Looks like this block code is included for the pc-i440fx-wily in focal branch and this is where any_layout is disabled: --- GlobalProperty hw_compat_2_3[] = { { "virtio-blk-pci", "any_layout", "off" }, { "virtio-balloon-pci", "any_layout", "off" }, { "virtio-serial-pci", "any_layout", "off" }, { "virtio-9p-pci", "any_layout", "off" }, { "virtio-rng-pci", "any_layout", "off" }, { TYPE_PCI_DEVICE, "x-pcie-lnksta-dllla", "off" }, { "migration", "send-configuration", "off" }, { "migration", "send-section-footer", "off" }, { "migration", "store-global-state", "off" }, }; --- * also we have another problem that *might* be linked to broken definition of pc-i440fx-wily. I am not sure so I'll just mention it (maybe it will be obvious for someone familiar with source code that this problem is also due to broken definition of pc-i440fx-wily in focal and hence part of the same issue) So even if migration bionic → focal succeeds, it's impossible to migrate guest back (focal → bionic). The problem is: --- operation failed: guest CPU doesn't match specification: extra features: arat --- ** Affects: libvirt (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/1902654 Title: failure to migrate virtual machines with pc-i440fx-wily type to ubuntu 20.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1902654/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs