When using VMIO 4.8 to migrate a RHV VM with USB enabled, the migration hangs. This is due to the validation rule #24 [1]: if VM.usb.enabled == true, then the migration is blocked. But when a migration is blocked, it hangs until the blocking condition is fixed, i.e. USB is disabled.

Kubevirt supports attaching USB devices to virtual machines, so the fact that USB is enabled shouldn't be a problem. The difficulty comes when a USB device is attached to the VM, as we possible have no way to migrate the USB device to Kubevirt.

The action plan would then be:

1. Identify whether a USB device is attached to the VM.
2. Implement a pre-migration rule in the controller to fail if that is the case.
3. List the USB device type that could be migrated.
4. Implement a USB device migration action for the listed USB devices.

[1] https://github.com/kubevirt/vm-import-operator/blob/master/docs/rules.md