# Re: \[PATCH v8 09/10\] vduse: Introduce VDUSE - vDPA Device in Userspace

- From: Jason Wang \<hidden\>
- Date: 2021-06-28 04:40:34 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/06/208814
- Thread: https://ratatoskr.run/netdev/2021/06/207854/t.md

```text

在 2021/6/25 下午12:19, Yongji Xie 写道:
>> 2b) for set_status(): simply relay the message to userspace, reply is no
>> needed. Userspace will use a command to update the status when the
>> datapath is stop. The the status could be fetched via get_stats().
>>
>> 2b looks more spec complaint.
>>
> Looks good to me. And I think we can use the reply of the message to
> update the status instead of introducing a new command.
>

Just notice this part in virtio_finalize_features():

        virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
        status = dev->config->get_status(dev);
        if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {

So we no reply doesn't work for FEATURES_OK.

So my understanding is:

1) We must not use noreply for set_status()
2) We can use noreply for get_status(), but it requires a new ioctl to update the status.

So it looks to me we need synchronize for both get_status() and set_status().

Thanks


```