nova.exception.InvalidCPUInfo: Unacceptable CPU info: CPU doesn't have compatibility.

Issue

• We are unable to live-migrate VM's from new compute node to older compute node and back and forth as we get the following error:

2022-10-27 12:28:10.620 7 ERROR oslo_messaging.rpc.server nova.exception.InvalidCPUInfo: Unacceptable CPU info: CPU doesn't have compatibility.

• The command virsh capabilities gave me the following cpu model:

      <model>Broadwell-IBRS</model>
      <vendor>Intel</vendor>

• But this should be an Ice Lake CPU according to the OS and the specs: Intel(R) Xeon(R) Gold 6338 CPU @ 2.00GHz

[root@overcloud-novacompute-13 ~]# cat /sys/devices/cpu/caps/pmu_name
icelake