Re: [PATCH v3 11/15] vhost-net: vhost-kernel: introduce vhost_net_virtqueue_restart()

[Kangjie Xu <kangjie.xu@linux.alibaba.com>]

在 2022/9/5 16:24, Jason Wang 写道:
>
> 在 2022/8/25 16:08, Kangjie Xu 写道:
>> Introduce vhost_net_virtqueue_restart(), which can restart the
>> specific virtqueue when the vhost net started running before.
>> If it fails to restart the virtqueue, the device will be stopped.
>>
>> Here we do not reuse vhost_net_start_one() or vhost_dev_start()
>> because they work at queue pair level. The mem table and features
>> do not change, so we can call the vhost_virtqueue_start() to
>> restart a specific queue.
>>
>> This patch only considers the case of vhost-kernel, when
>> NetClientDriver is NET_CLIENT_DRIVER_TAP.
>>
>> Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
>> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
>> ---
>>   hw/net/vhost_net.c      | 52 +++++++++++++++++++++++++++++++++++++++++
>>   include/net/vhost_net.h |  2 ++
>>   2 files changed, 54 insertions(+)
>>
>> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
>> index be51be98b3..0716f6cd96 100644
>> --- a/hw/net/vhost_net.c
>> +++ b/hw/net/vhost_net.c
>> @@ -536,3 +536,55 @@ void vhost_net_virtqueue_reset(VirtIODevice 
>> *vdev, NetClientState *nc,
>>         vhost_virtqueue_unmap(&net->dev, vdev, net->dev.vqs + idx, idx);
>>   }
>> +
>> +int vhost_net_virtqueue_restart(VirtIODevice *vdev, NetClientState *nc,
>> +                                int vq_index)
>> +{
>> +    VHostNetState *net = get_vhost_net(nc->peer);
>> +    const VhostOps *vhost_ops = net->dev.vhost_ops;
>> +    struct vhost_vring_file file = { };
>> +    int idx, r;
>> +
>> +    if (!net->dev.started) {
>> +        return 0;
>> +    }
>
>
> Should we return error in this case?
>
> Thanks

Yes, I think so. Will fix.

Thanks.

>
>> +
>> +    /* should only be called after backend is connected */
>> +    assert(vhost_ops);
>> +
>> +    idx = vhost_ops->vhost_get_vq_index(&net->dev, vq_index);
>> +
>> +    r = vhost_virtqueue_start(&net->dev,
>> +                              vdev,
>> +                              net->dev.vqs + idx,
>> +                              net->dev.vq_index + idx);
>> +    if (r < 0) {
>> +        goto err_start;
>> +    }
>> +
>> +    if (net->nc->info->type == NET_CLIENT_DRIVER_TAP) {
>> +        file.index = idx;
>> +        file.fd = net->backend;
>> +        r = vhost_net_set_backend(&net->dev, &file);
>> +        if (r < 0) {
>> +            r = -errno;
>> +            goto err_start;
>> +        }
>> +    }
>> +
>> +    return 0;
>> +
>> +err_start:
>> +    error_report("Error when restarting the queue.");
>> +
>> +    if (net->nc->info->type == NET_CLIENT_DRIVER_TAP) {
>> +        file.fd = -1;
>> +        file.index = idx;
>> +        int r = vhost_net_set_backend(&net->dev, &file);
>> +        assert(r >= 0);
>> +    }
>> +
>> +    vhost_dev_stop(&net->dev, vdev);
>> +
>> +    return r;
>> +}
>> diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
>> index 85d85a4957..40b9a40074 100644
>> --- a/include/net/vhost_net.h
>> +++ b/include/net/vhost_net.h
>> @@ -50,4 +50,6 @@ int vhost_net_set_mtu(struct vhost_net *net, 
>> uint16_t mtu);
>>     void vhost_net_virtqueue_reset(VirtIODevice *vdev, NetClientState 
>> *nc,
>>                                  int vq_index);
>> +int vhost_net_virtqueue_restart(VirtIODevice *vdev, NetClientState *nc,
>> +                                int vq_index);
>>   #endif