On Wed, Jun 17, 2020 at 5:19 AM Jason Wang [off-list ref] wrote:

On 2020/6/11 下午7:34, Michael S. Tsirkin wrote:

quoted

  static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
  {
      kfree(vq->descs);

@@ -394,6 +400,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
      for (i = 0; i < dev->nvqs; ++i) {
              vq = dev->vqs[i];
              vq->max_descs = dev->iov_limit;
+             if (vhost_vq_num_batch_descs(vq) < 0) {
+                     return -EINVAL;
+             }

This check breaks vdpa which set iov_limit to zero. Consider iov_limit
is meaningless to vDPA, I wonder we can skip the test when device
doesn't use worker.

I tested as

if (dev->use_worker && vhost_vq_num_batch_descs(vq) < 0)

In v9. Please let me know if that is ok for you.

Thanks!

Thanks