The virtnet_xdp_handler() is re-used. But 1. We need to copy data to create skb for XDP_PASS. 2. We need to call xsk_buff_free() to release the buffer. 3. The handle for xdp_buff is difference.
If we pushed this logic into existing receive handle(merge and small), we would have to maintain code scattered inside merge and small (and big). So I think it is a good choice for us to put the xsk code into an independent function. Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com> --- drivers/net/virtio/main.c | 40 ++++-- drivers/net/virtio/virtio_net.h | 4 + drivers/net/virtio/xsk.c | 216 ++++++++++++++++++++++++++++++++ drivers/net/virtio/xsk.h | 4 + 4 files changed, 251 insertions(+), 13 deletions(-) diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c index fb8dbce11e53..35f0daaea7e5 100644 --- a/drivers/net/virtio/main.c +++ b/drivers/net/virtio/main.c @@ -801,10 +801,10 @@ 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; @@ -1897,23 +1897,37 @@ static int virtnet_receive(struct virtnet_rq *rq, int budget, { struct virtnet_info *vi = rq->vq->vdev->priv; struct virtnet_rq_stats stats = {}; + void *buf, *ctx, *pctx = NULL; unsigned int len; int packets = 0; - void *buf; int i; - if (!vi->big_packets || vi->mergeable_rx_bufs) { - void *ctx; + if (rq->xsk.pool) { + struct sk_buff *skb; + + while (packets < budget) { + buf = virtqueue_get_buf(rq->vq, &len); + if (!buf) + break; + + skb = virtnet_receive_xsk_buf(vi, rq, buf, len, xdp_xmit, &stats); + if (skb) + virtnet_receive_done(vi, rq, skb); - while (packets < budget && - (buf = virtnet_rq_get_buf(rq, &len, &ctx))) { - receive_buf(vi, rq, buf, len, ctx, xdp_xmit, &stats); packets++; } } else { - while (packets < budget && - (buf = virtnet_rq_get_buf(rq, &len, NULL)) != NULL) { - receive_buf(vi, rq, buf, len, NULL, xdp_xmit, &stats); + if (!vi->big_packets || vi->mergeable_rx_bufs) + pctx = &ctx; + else + ctx = NULL; + + while (packets < budget) { + buf = virtnet_rq_get_buf(rq, &len, pctx); + if (!buf) + break; + + receive_buf(vi, rq, buf, len, ctx, xdp_xmit, &stats); packets++; } } diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h index c07a1e58bf0f..98dcf1825448 100644 --- a/drivers/net/virtio/virtio_net.h +++ b/drivers/net/virtio/virtio_net.h @@ -345,4 +345,8 @@ 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); +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); #endif diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c index c54cd08e9c77..6f4fa32b1184 100644 --- a/drivers/net/virtio/xsk.c +++ b/drivers/net/virtio/xsk.c @@ -14,6 +14,222 @@ static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len) sg->length = len; } +static void xsk_drop_follow_bufs(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_INC(dev, rx_length_errors); + break; + } + u64_stats_add(&stats->bytes, len); + xsk_buff_free(xdp); + } +} + +static struct xdp_buff *buf_to_xdp(struct virtnet_info *vi, + struct virtnet_rq *rq, void *buf, u32 len) +{ + struct xdp_buff *xdp; + u32 bufsize; + + xdp = (struct xdp_buff *)buf; + + bufsize = xsk_pool_get_rx_frame_size(rq->xsk.pool) + vi->hdr_len; + + if (unlikely(len > bufsize)) { + pr_debug("%s: rx error: len %u exceeds truesize %u\n", + vi->dev->name, len, bufsize); + DEV_STATS_INC(vi->dev, rx_length_errors); + xsk_buff_free(xdp); + return NULL; + } + + xsk_buff_set_size(xdp, len); + xsk_buff_dma_sync_for_cpu(xdp, rq->xsk.pool); + + return xdp; +} + +static int xsk_append_merge_buffer(struct virtnet_info *vi, + struct virtnet_rq *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 *xdp_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)) { + xsk_buff_free(xdp); + 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); + } + + xsk_buff_free(xdp); + + return skb; +} + +static struct sk_buff *virtnet_receive_xsk_merge(struct net_device *dev, struct virtnet_info *vi, + struct virtnet_rq *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 = xdp_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; +} + +struct sk_buff *virtnet_receive_xsk_buf(struct virtnet_info *vi, struct virtnet_rq *rq, + void *buf, u32 len, + unsigned int *xdp_xmit, + struct virtnet_rq_stats *stats) +{ + struct net_device *dev = vi->dev; + struct sk_buff *skb = NULL; + struct xdp_buff *xdp; + + len -= vi->hdr_len; + + u64_stats_add(&stats->bytes, len); + + xdp = buf_to_xdp(vi, rq, buf, len); + if (!xdp) + return NULL; + + if (unlikely(len < ETH_HLEN)) { + pr_debug("%s: short packet %i\n", dev->name, len); + DEV_STATS_INC(dev, rx_length_errors); + xsk_buff_free(xdp); + return NULL; + } + + if (vi->mergeable_rx_bufs) + skb = virtnet_receive_xsk_merge(dev, vi, rq, xdp, xdp_xmit, stats); + + return skb; +} + int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct virtnet_rq *rq, struct xsk_buff_pool *pool, gfp_t gfp) { diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h index bef41a3f954e..e78fcd0a4946 100644 --- a/drivers/net/virtio/xsk.h +++ b/drivers/net/virtio/xsk.h @@ -25,4 +25,8 @@ bool virtnet_xsk_xmit(struct virtnet_sq *sq, struct xsk_buff_pool *pool, int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag); int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct virtnet_rq *rq, struct xsk_buff_pool *pool, gfp_t gfp); +struct sk_buff *virtnet_receive_xsk_buf(struct virtnet_info *vi, struct virtnet_rq *rq, + void *buf, u32 len, + unsigned int *xdp_xmit, + struct virtnet_rq_stats *stats); #endif -- 2.32.0.3.g01195cf9f