Re: [PATCH net-next v6 05/10] virtio_net: xsk: bind/unbind xsk for rx

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

On Fri, 28 Jun 2024 10:19:34 +0800, Jason Wang <jasowang@redhat.com> wrote:
> On Tue, Jun 18, 2024 at 3:57 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
> >
> > This patch implement the logic of bind/unbind xsk pool to rq.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> >  drivers/net/virtio_net.c | 133 +++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 133 insertions(+)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index df885cdbe658..d8cce143be26 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -25,6 +25,7 @@
> >  #include <net/net_failover.h>
> >  #include <net/netdev_rx_queue.h>
> >  #include <net/netdev_queues.h>
> > +#include <net/xdp_sock_drv.h>
> >
> >  static int napi_weight = NAPI_POLL_WEIGHT;
> >  module_param(napi_weight, int, 0444);
> > @@ -348,6 +349,13 @@ struct receive_queue {
> >
> >         /* Record the last dma info to free after new pages is allocated. */
> >         struct virtnet_rq_dma *last_dma;
> > +
> > +       struct {
> > +               struct xsk_buff_pool *pool;
> > +
> > +               /* xdp rxq used by xsk */
> > +               struct xdp_rxq_info xdp_rxq;
> > +       } xsk;
>
> I don't see a special reason for having a container struct here.


Will fix.

>
>
> >  };
> >
> >  /* This structure can contain rss message with maximum settings for indirection table and keysize
> > @@ -4970,6 +4978,129 @@ static int virtnet_restore_guest_offloads(struct virtnet_info *vi)
> >         return virtnet_set_guest_offloads(vi, offloads);
> >  }
> >
> > +static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queue *rq,
> > +                                   struct xsk_buff_pool *pool)
> > +{
> > +       int err, qindex;
> > +
> > +       qindex = rq - vi->rq;
> > +
> > +       if (pool) {
> > +               err = xdp_rxq_info_reg(&rq->xsk.xdp_rxq, vi->dev, qindex, rq->napi.napi_id);
> > +               if (err < 0)
> > +                       return err;
> > +
> > +               err = xdp_rxq_info_reg_mem_model(&rq->xsk.xdp_rxq,
> > +                                                MEM_TYPE_XSK_BUFF_POOL, NULL);
> > +               if (err < 0)
> > +                       goto unreg;
> > +
> > +               xsk_pool_set_rxq_info(pool, &rq->xsk.xdp_rxq);
> > +       }
> > +
> > +       virtnet_rx_pause(vi, rq);
> > +
> > +       err = virtqueue_reset(rq->vq, virtnet_rq_unmap_free_buf);
> > +       if (err) {
> > +               netdev_err(vi->dev, "reset rx fail: rx queue index: %d err: %d\n", qindex, err);
> > +
> > +               pool = NULL;
> > +       }
> > +
> > +       rq->xsk.pool = pool;
> > +
> > +       virtnet_rx_resume(vi, rq);
> > +
> > +       if (pool)
> > +               return 0;
> > +
> > +unreg:
> > +       xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> > +       return err;
> > +}
> > +
> > +static int virtnet_xsk_pool_enable(struct net_device *dev,
> > +                                  struct xsk_buff_pool *pool,
> > +                                  u16 qid)
> > +{
> > +       struct virtnet_info *vi = netdev_priv(dev);
> > +       struct receive_queue *rq;
> > +       struct device *dma_dev;
> > +       struct send_queue *sq;
> > +       int err;
> > +
> > +       /* In big_packets mode, xdp cannot work, so there is no need to
> > +        * initialize xsk of rq.
> > +        */
> > +       if (vi->big_packets && !vi->mergeable_rx_bufs)
> > +               return -ENOENT;
> > +
> > +       if (qid >= vi->curr_queue_pairs)
> > +               return -EINVAL;
> > +
> > +       sq = &vi->sq[qid];
> > +       rq = &vi->rq[qid];
> > +
> > +       /* For the xsk, the tx and rx should have the same device. The af-xdp
> > +        * may use one buffer to receive from the rx and reuse this buffer to
> > +        * send by the tx. So the dma dev of sq and rq should be the same one.
> > +        *
> > +        * But vq->dma_dev allows every vq has the respective dma dev. So I
> > +        * check the dma dev of vq and sq is the same dev.
>
> Not a native speaker, but it might be better to say "xsk assumes ....
> to be the same device". And it might be better to replace "should"
> with "must".

Will fix.

Thanks.


>
> Others look good.
>
> Thanks
>