HVM linux VM dies after storage migration to 7.6 from older XS

Hello Xenserver team.

XCP-ng's issue tracker got an interesting bug report from a user, confirmed by another one and reproduced on XenServer 7.6 by myself: https://github.com/xcp-ng/xcp/issues/111

Live migration of a VM that is on local storage seemingly succeeds, status of the VM is "running", but there's no console or network activity anymore. Rebooting the VM allows to get it back, but as they said in the bug report, this defeats the concept of live migration.

As the user said in the above bug report, here are the conditions to reproduce:

• Linux VM (multiple distributions tested, for example Centos 7.6)
• HVM (no problem with PV)
• Initially running on XS < 7.6
• Migrated to XS 7.6 (different pool, since storage motion is not possible during RPU)

Best regards