What were you trying to do that didn't work?

While trying to reproduce postcopy live migration issue RHEL-27832, libvirtd logged internal error saying:

# virsh migrate --verbose --persistent \
    --postcopy --postcopy-after-precopy \
    --timeout 3 --timeout-postcopy --live \
     $GUEST qemu+ssh://$DSTHOST/system
libvirtd[184607]: internal error: unable to execute QEMU command 'migrate-start-postcopy': Enable postcopy with migrate_set_capability before the start of migration

Please provide the package NVR for which bug is seen:

# rpm -q qemu-kvm libvirt libvirt-daemon kernel-rt

qemu-kvm-9.0.0-3.el9.x86_64
libvirt-10.4.0-1.el9.x86_64
libvirt-daemon-10.4.0-1.el9.x86_64
kernel-rt-5.14.0-463.el9.x86_64

How reproducible:

Each time - 100%

Steps to reproduce

1. Set up migration across two machines with above packages and NFS share.
2. Run postcopy migration with above command
3. libvirtd(8) logs error to be seen with $ journalctl -fu libvirtd

Expected results

• libvirtd(8) does postcopy live migration without errors.

  Actual results

libvirtd(8) logs following error:

libvirtd[184607]: internal error: unable to execute QEMU command 'migrate-start-postcopy': Enable postcopy with migrate_set_capability before the start of migration