Problem Description:

The control virtqueue implementation in DPDK Vhost library wraps the avail and used indexes to the ring size whereas the driver expects to do this operation by itself.

It results in the driver to never notify the device new messages are available, and makes the device implementation to access random memory, resulting segmentation faults and other kind of unpredictable behaviors.

With the fix implemented, control queue should also be tested without VIRTIO_F_EVENT_IDX feature negotiated.