On Mon, Oct 16, 2023 at 8:01 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> Implementing the logic of xsk rx. If this packet is not for XSK
> determined in XDP, then we need to copy once to generate a SKB.
> If it is for XSK, it is a zerocopy receive packet process.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/net/virtio/main.c | 14 ++--
> drivers/net/virtio/virtio_net.h | 4 ++
> drivers/net/virtio/xsk.c | 120 ++++++++++++++++++++++++++++++++
> drivers/net/virtio/xsk.h | 4 ++
> 4 files changed, 137 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> index 0e740447b142..003dd67ab707 100644
> --- a/drivers/net/virtio/main.c
> +++ b/drivers/net/virtio/main.c
> @@ -822,10 +822,10 @@ static void put_xdp_frags(struct xdp_buff *xdp)
> }
> }
>
> -static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> - struct net_device *dev,
> - unsigned int *xdp_xmit,
> - struct virtnet_rq_stats *stats)
> +int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> + struct net_device *dev,
> + unsigned int *xdp_xmit,
> + struct virtnet_rq_stats *stats)
> {
> struct xdp_frame *xdpf;
> int err;
> @@ -1589,13 +1589,17 @@ static void receive_buf(struct virtnet_info *vi, struct virtnet_rq *rq,
> return;
> }
>
> - if (vi->mergeable_rx_bufs)
> + rcu_read_lock();
> + if (rcu_dereference(rq->xsk.pool))
> + skb = virtnet_receive_xsk(dev, vi, rq, buf, len, xdp_xmit, stats);
> + else if (vi->mergeable_rx_bufs)
> skb = receive_mergeable(dev, vi, rq, buf, ctx, len, xdp_xmit,
> stats);
> else if (vi->big_packets)
> skb = receive_big(dev, vi, rq, buf, len, stats);
> else
> skb = receive_small(dev, vi, rq, buf, ctx, len, xdp_xmit, stats);
> + rcu_read_unlock();
>
> if (unlikely(!skb))
> return;
> diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> index 6e71622fca45..fd7f34703c9b 100644
> --- a/drivers/net/virtio/virtio_net.h
> +++ b/drivers/net/virtio/virtio_net.h
> @@ -346,6 +346,10 @@ static inline bool virtnet_is_xdp_raw_buffer_queue(struct virtnet_info *vi, int
> return false;
> }
>
> +int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
> + struct net_device *dev,
> + unsigned int *xdp_xmit,
> + struct virtnet_rq_stats *stats);
> void virtnet_rx_pause(struct virtnet_info *vi, struct virtnet_rq *rq);
> void virtnet_rx_resume(struct virtnet_info *vi, struct virtnet_rq *rq);
> void virtnet_tx_pause(struct virtnet_info *vi, struct virtnet_sq *sq);
> diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> index 841fb078882a..f1c64414fac9 100644
> --- a/drivers/net/virtio/xsk.c
> +++ b/drivers/net/virtio/xsk.c
> @@ -13,6 +13,18 @@ static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
> sg->length = len;
> }
>
> +static unsigned int virtnet_receive_buf_num(struct virtnet_info *vi, char *buf)
> +{
> + struct virtio_net_hdr_mrg_rxbuf *hdr;
> +
> + if (vi->mergeable_rx_bufs) {
> + hdr = (struct virtio_net_hdr_mrg_rxbuf *)buf;
> + return virtio16_to_cpu(vi->vdev, hdr->num_buffers);
> + }
> +
> + return 1;
> +}
> +
> static void virtnet_xsk_check_queue(struct virtnet_sq *sq)
> {
> struct virtnet_info *vi = sq->vq->vdev->priv;
> @@ -37,6 +49,114 @@ static void virtnet_xsk_check_queue(struct virtnet_sq *sq)
> netif_stop_subqueue(dev, qnum);
> }
>
> +static void merge_drop_follow_xdp(struct net_device *dev,
> + struct virtnet_rq *rq,
> + u32 num_buf,
> + struct virtnet_rq_stats *stats)
> +{
> + struct xdp_buff *xdp;
> + u32 len;
> +
> + while (num_buf-- > 1) {
> + xdp = virtqueue_get_buf(rq->vq, &len);
> + if (unlikely(!xdp)) {
> + pr_debug("%s: rx error: %d buffers missing\n",
> + dev->name, num_buf);
> + dev->stats.rx_length_errors++;
> + break;
> + }
> + stats->bytes += len;
> + xsk_buff_free(xdp);
> + }
> +}
> +
> +static struct sk_buff *construct_skb(struct virtnet_rq *rq,
> + struct xdp_buff *xdp)
> +{
> + unsigned int metasize = xdp->data - xdp->data_meta;
> + struct sk_buff *skb;
> + unsigned int size;
> +
> + size = xdp->data_end - xdp->data_hard_start;
> + skb = napi_alloc_skb(&rq->napi, size);
> + if (unlikely(!skb))
> + return NULL;
> +
> + skb_reserve(skb, xdp->data_meta - xdp->data_hard_start);
> +
> + size = xdp->data_end - xdp->data_meta;
> + memcpy(__skb_put(skb, size), xdp->data_meta, size);
> +
> + if (metasize) {
> + __skb_pull(skb, metasize);
> + skb_metadata_set(skb, metasize);
> + }
> +
> + return skb;
> +}
> +
> +struct sk_buff *virtnet_receive_xsk(struct net_device *dev, struct virtnet_info *vi,
> + struct virtnet_rq *rq, void *buf,
> + unsigned int len, unsigned int *xdp_xmit,
> + struct virtnet_rq_stats *stats)
> +{
I wonder if anything blocks us from reusing the existing XDP logic?
Are there some subtle differences?
Thanks
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