Commit 99c861b4 authored by Xuan Zhuo's avatar Xuan Zhuo Committed by Jakub Kicinski
Browse files

virtio_net: xsk: rx: support recv merge mode 



Support AF-XDP for merge mode.

Signed-off-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20240708112537.96291-11-xuanzhuo@linux.alibaba.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a4e7ba70

drivers/net/virtio_net.c

+144 −0
Original line number Diff line number Diff line
@@ -504,6 +504,10 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp, 
			       struct virtnet_rq_stats *stats);

static void virtnet_receive_done(struct virtnet_info *vi, struct receive_queue *rq,

				 struct sk_buff *skb, u8 flags);

static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,

					       struct sk_buff *curr_skb,

					       struct page *page, void *buf,

					       int len, int truesize);



static bool is_xdp_frame(void *ptr)

{
@@ -984,6 +988,11 @@ static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf) 


	rq = &vi->rq[i];



	if (rq->xsk_pool) {

		xsk_buff_free((struct xdp_buff *)buf);

		return;

	}



	if (!vi->big_packets || vi->mergeable_rx_bufs)

		virtnet_rq_unmap(rq, buf, 0);
@@ -1152,6 +1161,139 @@ static struct sk_buff *virtnet_receive_xsk_small(struct net_device *dev, struct 
	}

}



static void xsk_drop_follow_bufs(struct net_device *dev,

				 struct receive_queue *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_INC(dev, rx_length_errors);

			break;

		}

		u64_stats_add(&stats->bytes, len);

		xsk_buff_free(xdp);

	}

}



static int xsk_append_merge_buffer(struct virtnet_info *vi,

				   struct receive_queue *rq,

				   struct sk_buff *head_skb,

				   u32 num_buf,

				   struct virtio_net_hdr_mrg_rxbuf *hdr,

				   struct virtnet_rq_stats *stats)

{

	struct sk_buff *curr_skb;

	struct xdp_buff *xdp;

	u32 len, truesize;

	struct page *page;

	void *buf;



	curr_skb = head_skb;



	while (--num_buf) {

		buf = virtqueue_get_buf(rq->vq, &len);

		if (unlikely(!buf)) {

			pr_debug("%s: rx error: %d buffers out of %d missing\n",

				 vi->dev->name, num_buf,

				 virtio16_to_cpu(vi->vdev,

						 hdr->num_buffers));

			DEV_STATS_INC(vi->dev, rx_length_errors);

			return -EINVAL;

		}



		u64_stats_add(&stats->bytes, len);



		xdp = buf_to_xdp(vi, rq, buf, len);

		if (!xdp)

			goto err;



		buf = napi_alloc_frag(len);

		if (!buf) {

			xsk_buff_free(xdp);

			goto err;

		}



		memcpy(buf, xdp->data - vi->hdr_len, len);



		xsk_buff_free(xdp);



		page = virt_to_page(buf);



		truesize = len;



		curr_skb  = virtnet_skb_append_frag(head_skb, curr_skb, page,

						    buf, len, truesize);

		if (!curr_skb) {

			put_page(page);

			goto err;

		}

	}



	return 0;



err:

	xsk_drop_follow_bufs(vi->dev, rq, num_buf, stats);

	return -EINVAL;

}



static struct sk_buff *virtnet_receive_xsk_merge(struct net_device *dev, struct virtnet_info *vi,

						 struct receive_queue *rq, struct xdp_buff *xdp,

						 unsigned int *xdp_xmit,

						 struct virtnet_rq_stats *stats)

{

	struct virtio_net_hdr_mrg_rxbuf *hdr;

	struct bpf_prog *prog;

	struct sk_buff *skb;

	u32 ret, num_buf;



	hdr = xdp->data - vi->hdr_len;

	num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);



	ret = XDP_PASS;

	rcu_read_lock();

	prog = rcu_dereference(rq->xdp_prog);

	/* TODO: support multi buffer. */

	if (prog && num_buf == 1)

		ret = virtnet_xdp_handler(prog, xdp, dev, xdp_xmit, stats);

	rcu_read_unlock();



	switch (ret) {

	case XDP_PASS:

		skb = xsk_construct_skb(rq, xdp);

		if (!skb)

			goto drop_bufs;



		if (xsk_append_merge_buffer(vi, rq, skb, num_buf, hdr, stats)) {

			dev_kfree_skb(skb);

			goto drop;

		}



		return skb;



	case XDP_TX:

	case XDP_REDIRECT:

		return NULL;



	default:

		/* drop packet */

		xsk_buff_free(xdp);

	}



drop_bufs:

	xsk_drop_follow_bufs(dev, rq, num_buf, stats);



drop:

	u64_stats_inc(&stats->drops);

	return NULL;

}



static void virtnet_receive_xsk_buf(struct virtnet_info *vi, struct receive_queue *rq,

				    void *buf, u32 len,

				    unsigned int *xdp_xmit,
@@ -1181,6 +1323,8 @@ static void virtnet_receive_xsk_buf(struct virtnet_info *vi, struct receive_queu 


	if (!vi->mergeable_rx_bufs)

		skb = virtnet_receive_xsk_small(dev, vi, rq, xdp, xdp_xmit, stats);

	else

		skb = virtnet_receive_xsk_merge(dev, vi, rq, xdp, xdp_xmit, stats);



	if (skb)

		virtnet_receive_done(vi, rq, skb, flags);