Description of problem:
Start VM with disk setting dedicatedIOThread:true, hotplug disk and make persistent, restart VM failed with "LibvirtError:'unsupported configuration: IOThreads not available for bus scsi target sda')"

Version-Release number of selected component (if applicable):
CNV 4.14

How reproducible:
100%

Steps to Reproduce:
1. Create VM with dedicatedIOThread in yaml file: asb-vm-dv-nfs-rhel.yaml,
Login to VM console, check there is one disk:/dev/vda

1. oc create -f asb-pv-dv-nfs-rhel.yaml
   persistentvolume/asb-pv-dv-nfs-rhel created
2. oc create -f asb-vm-dv-nfs-rhel.yaml
   virtualmachine.kubevirt.io/asb-vm-dv-nfs-rhel created
3. oc get vm
   NAME AGE STATUS READY
   asb-vm-dv-nfs-rhel 74s Running True

2. Create PV and PVC

1. oc create -f asb-hotplug-pv-disk.yaml
   persistentvolume/asb-hotplug-pv-disk created
2. oc create -f asb-hotplug-pvc-disk.yaml
   persistentvolumeclaim/asb-hotplug-pvc-disk created

1. oc get pv|grep asb
   asb-hotplug-pv-disk 4Gi RWX Retain Bound default/asb-hotplug-pvc-disk nfs 4m25s
   asb-pv-dv-nfs-rhel 12Gi RWX Retain Bound default/asb-dv-nfs-rhel nfs 4m35s
2. oc get pvc|grep asb
   asb-dv-nfs-rhel Bound asb-pv-dv-nfs-rhel 12Gi RWX nfs 4m19s
   asb-hotplug-pvc-disk Bound asb-hotplug-pv-disk 4Gi RWX nfs 4m24s

3. Hotplug PVC: asb-hotplug-pvc-disk to VM: asb-vm-dv-nfs-rhel in webconsole:
VirtualMachines -> Configuration -> Disks -> Add disk:
Name: hotplug-disk Source: Use an existing PVC PVC project: default
PVC name: asb-hotplug-pvc-disk Type: Disk Interface: SCSI
Click Save. Check the Events, there is no error, check in VM Console: there are two disks: /dev/vda, /dev/sda.

4. VirtualMachines -> Configuration -> Disks -> Name: hotplug-disk: Make persistent, click Save. Check the disk xml, the hotpluged scsi disk with io='threads'

1. oc get vm
   NAME AGE STATUS READY
   asb-vm-dv-nfs-rhel 6m34s Running True

1. oc get pod|grep virt-launcher
   virt-launcher-asb-vm-dv-nfs-rhel-6d8jx 1/1 Running 0 5m41s

1. oc rsh virt-launcher-asb-vm-dv-nfs-rhel-6d8jx
   sh-5.1$ virsh list --all
   Id Name State
   --------------------------------------------
   1 default_asb-vm-dv-nfs-rhel running

sh-5.1$ virsh dumpxml default_asb-vm-dv-nfs-rhel| grep disk -A 15
<disk type='file' device='disk' model='virtio-non-transitional'>
<driver name='qemu' type='raw' cache='none' error_policy='stop' discard='unmap' iothread='1' queues='2'/>
<source file='/var/run/kubevirt-private/vmi-disks/rootdisk/disk.img' index='1'/>
<backingStore/>
<target dev='vda' bus='virtio'/>
<boot order='1'/>
<alias name='ua-rootdisk'/>
<address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
</disk>
<disk type='file' device='disk'>
<driver name='qemu' type='raw' cache='none' error_policy='stop' io='threads' discard='unmap'/>
<source file='/var/run/kubevirt/hotplug-disks/hotplug-disk.img' index='2'/>
<backingStore/>
<target dev='sda' bus='scsi'/>
<alias name='ua-hotplug-disk'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>

5. Restart the VM by click Actions: Restart, VM failed to start with error message:
"LibvirtError(Code=67, Domain=10, Message='unsupported configuration: IOThreads not available for bus scsi target sda')"

1. oc get vm
   NAME AGE STATUS READY
   asb-vm-dv-nfs-rhel 90m Starting False

1. oc get vm
   NAME AGE STATUS READY
   asb-vm-dv-nfs-rhel 37m CrashLoopBackOff False

6. Collect the VM yaml file and virt-launcher pod logs

1. oc describe vm asb-vm-dv-nfs-rhel > describe-vm-asb-vm-dv-nfs-rhel
2. oc get vm asb-vm-dv-nfs-rhel -o yaml > get-vm-asb-vm-dv-nfs-rhel-yaml
3. oc get pod|grep virt-launcher
   virt-launcher-asb-vm-dv-nfs-rhel-v56kb 1/1 Running 0 100s
4. oc logs virt-launcher-asb-vm-dv-nfs-rhel-v56kb > virt-launcher-asb-vm-dv-nfs-rhel-v56kb.log

Actual results:
In step 4, the hotpluged scsi disk xml with io='threads', in step 5, VM failed to start

Expected results:
After hotplug scsi disk In step 4, In step5, Restart VM successfully.

Additional info:

• Attached files:
• VM, PV yaml files: asb-pv-dv-nfs-rhel.yaml, asb-vm-dv-nfs-rhel.yaml, asb-hotplug-pvc-disk.yaml, asb-hotplug-pv-disk.yaml
• VM, Pod logs: describe-vm-asb-vm-dv-nfs-rhel, get-vm-asb-vm-dv-nfs-rhel-yaml, virt-launcher-asb-vm-dv-nfs-rhel-v56kb.log