VM migration fails due "Spice-CRITICAL" errors in qemu and libvirtd logs

Issue

• VM migration fails.

• No obvious errors in VDSM logs on either host.

• libvirtd logs on the destination host contain;

id 0, group 0, virt start 0, virt end ffffffffffffffff, generation 0, delta 0
id 1, group 1, virt start 7fe84f200000, virt end 7fe8571fe000, generation 0, delta 7fe84f200000
id 2, group 1, virt start 7fe84d000000, virt end 7fe84f000000, generation 0, delta 7fe84d000000
((null):20582): Spice-CRITICAL **: red_memslots.c:123:get_virt: slot_id 128 too big, addr=800000000f000000

• The qemu log for the VM on the destination host also contains;

id 0, group 0, virt start 0, virt end ffffffffffffffff, generation 0, delta 0
id 1, group 1, virt start 7f180ba00000, virt end 7f18139fe000, generation 0, delta 7f180ba00000
id 2, group 1, virt start 7f1809800000, virt end 7f180b800000, generation 0, delta 7f1809800000
((null):55282): Spice-CRITICAL **: red_memslots.c:123:get_virt: slot_id 80 too big, addr=5000000000000000

• Migration is successful if the VM was restarted.

• It would then fail to migrate only after opening a Spice console sesssion.