vdpa: Block vq property changes in DRIVER_OK

The virtio standard doesn't allow for virtqueue address and state
changes when the device is in DRIVER_OK. Return an error in such cases
unless the device is suspended.

The suspended device exception is needed because some devices support
virtqueue changes when the device is suspended.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Suggested-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20231225134210.151540-3-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vdpa.c

@@ -703,6 +703,9 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 
 	switch (cmd) {
 	case VHOST_SET_VRING_ADDR:
+		if ((ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK) && !v->suspended)
+			return -EINVAL;
+
 		if (ops->set_vq_address(vdpa, idx,
 					(u64)(uintptr_t)vq->desc,
 					(u64)(uintptr_t)vq->avail,
@@ -711,6 +714,9 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 		break;
 
 	case VHOST_SET_VRING_BASE:
+		if ((ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK) && !v->suspended)
+			return -EINVAL;
+
 		if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
 			vq_state.packed.last_avail_idx = vq->last_avail_idx & 0x7fff;
 			vq_state.packed.last_avail_counter = !!(vq->last_avail_idx & 0x8000);