---
upgrade:
  - |
    On AArch64 architecture ``cpu_mode`` for libvirt is set to ``host-passthrough``
    by default.

    AArch64 currently lacks ``host-model`` support because neither libvirt nor
    QEMU are able to tell what the host CPU model exactly is and there is no
    CPU description code for ARM(64) at this point.

    .. warning:: ``host-passthrough`` mode will completely break live
       migration, *unless* all the Compute nodes (running libvirtd) have
       *identical* CPUs.