A virtio descriptor constraints with C representative.
Taken from Virtio spec:
https://docs.oasis-open.org/virtio/virtio/v1.1/csprd01/virtio-v1.1-csprd01.html#x1-430008
2.6.5 The Virtqueue Descriptor Table
Error type indicating the guest configured a virtio queue such that the avail_idx field would
indicate there are more descriptors to process than the queue actually has space for.
A virtio used element in the used ring.
Taken from Virtio spec:
https://docs.oasis-open.org/virtio/virtio/v1.1/csprd01/virtio-v1.1-csprd01.html#x1-430008
2.6.8 The Virtqueue Used Ring