Live migration of VM fails due to missing /dev/hwrng after FFU from RHOSP13 to 16.2

Issue

• After upgrading RHOSP 13 to 16.2 there is a problem with migrating VMs. Initially, the live migration failed and the VM was in a FAILED state. Now, live migration is working, but cold migration, which is used with the Telco servers, is not. During the cold migration, the server is shutdown, resize is confirmed, brought up on the other node. However, the server crashes during the boot with the non-volatile memory driver step.

• Live-Migrate a VM failed and the ACTIVE server is now in FAILED state:

  ERROR MESSAGE:  libvirtError(\'virDomainCreateWithFlags()    failed\')\nlibvirt.libvirtError: internal error: process exited while connecting to monitor:    2023-04-05T18:18:59.297330Z qemu-kvm: -object rng-random,id=objrng0,filename=/dev/hwrng: Could not open \'/dev/hwrng\': Permission denied\n'}

• After changing permissions of /dev/hwrng, VMs will not boot and crash with the following error message in the qemu.log:

ERROR:../backends/rng-random.c:48:entropy_available: assertion failed: (len != -1)
2023-04-07 19:45:25.984+0000: shutting down, reason=crashed