vhost: fix unsafe vring addresses modifications

This patch adds missing protection around vring_invalidate
and translate_ring_addresses calls in vhost_user_iotlb_msg.

Fixes: eefac95 ("vhost: postpone device creation until rings are mapped")
Cc: stable@dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>

lib/vhost/vhost_user.c

@@ -2564,8 +2564,11 @@ vhost_user_iotlb_msg(struct virtio_net **pdev,
 			vhost_user_iotlb_cache_insert(dev, vq, imsg->iova, vva,
 					len, imsg->perm);
 
-			if (is_vring_iotlb(dev, vq, imsg))
+			if (is_vring_iotlb(dev, vq, imsg)) {
+				rte_spinlock_lock(&vq->access_lock);
 				*pdev = dev = translate_ring_addresses(dev, i);
+				rte_spinlock_unlock(&vq->access_lock);
+			}
 		}
 		break;
 	case VHOST_IOTLB_INVALIDATE:
@@ -2578,8 +2581,11 @@ vhost_user_iotlb_msg(struct virtio_net **pdev,
 			vhost_user_iotlb_cache_remove(vq, imsg->iova,
 					imsg->size);
 
-			if (is_vring_iotlb(dev, vq, imsg))
+			if (is_vring_iotlb(dev, vq, imsg)) {
+				rte_spinlock_lock(&vq->access_lock);
 				vring_invalidate(dev, vq);
+				rte_spinlock_unlock(&vq->access_lock);
+			}
 		}
 		break;
 	default: