Unable to start KVM in ubuntu_kvm_smoke_test with 5.15 and newer kernels on openstack

This issue pops up after adding openstack support.

The ubuntu_kvm_smoke_test on openstack AMD64 instance works with:
  * X-hwe-4.15
  * B-4.15
  * B-5.4
  * F-5.4

It looks like the nested KVM does not work since F-5.15.

With a manual test on J-5.15. From virsh console it looks like the KVM was not started successfully:

[ 10.681762] raid6: using algorithm avx2x2 gen() 16463 MB/s
[ 10.687858] raid6: .... xor() 10100 MB/s, rmw enabled
[ 10.693645] raid6: using avx2x2 recovery algorithm
[ 10.719239] xor: automatically using best checksumming function avx
[ 10.751765] async_tx: api initialized (async)
done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
Begin: Running /scripts/local-premount ... [ 11.087664] Btrfs loaded, crc32c=crc32c-intel, zoned=yes, fsverity=yes
Scanning for Btrfs filesystems
done.
Warning: fsck not present, so skipping root file system
[ 11.165607] EXT4-fs (vda1): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
done.
Begin: Running /scripts/local-bottom ... done.
Begin: Running /scripts/init-bottom ... done.
(Stopped here)

Please find the attachment for the complete virsh console output.