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 <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 142 +++++++++++++++++++++++++++++++++++++--
1 file changed, 138 insertions(+), 4 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a780dcc4dd4f..1a4fd8e744e0 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -533,8 +533,10 @@ struct virtio_net_common_hdr {
static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
static void virtnet_xsk_completed(struct send_queue *sq, int num);
-static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct receive_queue *rq,
- struct xsk_buff_pool *pool, gfp_t gfp);
+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);
enum virtnet_xmit_type {
VIRTNET_XMIT_TYPE_SKB,
@@ -1209,6 +1211,11 @@ 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);
@@ -1299,6 +1306,120 @@ static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
sg->length = len;
}
+static struct xdp_buff *buf_to_xdp(struct virtnet_info *vi,
+ struct receive_queue *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);
+
+ return xdp;
+}
+
+static struct sk_buff *xdp_construct_skb(struct receive_queue *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_small(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 bpf_prog *prog;
+ u32 ret;
+
+ ret = XDP_PASS;
+ rcu_read_lock();
+ prog = rcu_dereference(rq->xdp_prog);
+ if (prog)
+ ret = virtnet_xdp_handler(prog, xdp, dev, xdp_xmit, stats);
+ rcu_read_unlock();
+
+ switch (ret) {
+ case XDP_PASS:
+ return xdp_construct_skb(rq, xdp);
+
+ case XDP_TX:
+ case XDP_REDIRECT:
+ return NULL;
+
+ default:
+ /* drop packet */
+ xsk_buff_free(xdp);
+ u64_stats_inc(&stats->drops);
+ return NULL;
+ }
+}
+
+static struct sk_buff *virtnet_receive_xsk_buf(struct virtnet_info *vi, struct receive_queue *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_small(dev, vi, rq, xdp, xdp_xmit, stats);
+
+ return skb;
+}
+
static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct receive_queue *rq,
struct xsk_buff_pool *pool, gfp_t gfp)
{
@@ -2704,9 +2825,22 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
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);
+
+ packets++;
+ }
+ } else if (!vi->big_packets || vi->mergeable_rx_bufs) {
+ void *ctx;
while (packets < budget &&
(buf = virtnet_rq_get_buf(rq, &len, &ctx))) {
receive_buf(vi, rq, buf, len, ctx, xdp_xmit, &stats);
--
2.32.0.3.g01195cf9f
