[dpdk-dev] [PATCH] net/virtio-user: send kick to tx queue to notify backend on initialization

[Maxime Coquelin]

Hi Steven,

On 08/01/2017 06:17 PM, Steven wrote:
> Acccording to the spec, https://fossies.org/linux/qemu/docs/specs/vhost-user.txt
> 
> client must start ring upon receiving a kick (that is, detecting that file
> descriptor is reachable) on the descriptor specified by
> VHOST_USER_SET_VRING_KICK.
> 
> The code sends a kick to the rx queue. It is missing sending a kick for the
> tx queue. This patch is to add the missing code to comply with the spec.
> 
> Signed-off-by: Steven <sluong at cisco.com>
> ---
>   drivers/net/virtio/virtio_ethdev.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index 00a3122..6362e14 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -1747,6 +1747,11 @@ virtio_dev_start(struct rte_eth_dev *dev)
>   		virtqueue_notify(rxvq->vq);
>   	}
>   
> +	for (i = 0; i < dev->data->nb_tx_queues; i++) {
> +		txvq = dev->data->tx_queues[i];
> +		virtqueue_notify(txvq->vq);
> +	}
> +

I'm not sure to get why we would need to send Txq notification whereas
no packet have been enqueued. That said, I don't think it hurts.

Steven, does it solve a real problem you are facing with virtio-user?

Yuanhan, what's your opinion on this?

Cheers,
Maxime