func: int vhost_backend_invalidate_device_iotlb(struct vhost_dev *dev,
  
                                                   uint64_t iova, uint64_t len)
  
  {
  
      struct vhost_iotlb_msg imsg;
  
  
  
      imsg.iova = iova;
  
      imsg.size = len;
  
      imsg.type = VHOST_IOTLB_INVALIDATE;
  
  
  
      return dev->vhost_ops->vhost_send_device_iotlb_msg(dev, &imsg);
  
  }
  