Unable to live migrate VMs on AMD hardware

If you are running XenServer on any AMD Family 15h or 16h CPU (including Opteron 42xx, 43xx, 62xx, 63xx and 63xxP processors), attempts to live migrate a VM to a host that has an updated microcode (version 0x600063e) can fail with a VM_INCOMPATIBLE_WITH_THIS_HOST error. This is due to a CPU feature incompatibility issue.

The affected processors with microcode 0x600063e (or later) do not have the Light-Weight Profiling (LWP) feature which was present in previous microcode versions. Therefore, if you live migrate a VM running on a host that has the LWP feature to a host that does not have this feature, migration fails with a VM_INCOMPATIBLE_WITH_THIS_HOST error.

Environment

This issue occurs on AMD processors noted above with an updated microcode (version 0x600063e). The microcode version can change when you update your BIOS, install a XenServer update, or upgrade your XenServer host to a newer version.

Note that the following XenServer updates contain affected AMD microcode versions:

Releases of XenServer up to XenServer 7.5 do not include the affected AMD microcode until you apply one of the updates listed above.

To check the CPU microcode version:

  1. On a XenServer host, open a local shell and log on as ‘root’.
  2. Run the following command:
# cat /proc/cpuinfo | grep microcode

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