On Fri, Jun 14, 2024 at 2:40 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> The driver's tx napi is very important for XSK. It is responsible for
> obtaining data from the XSK queue and sending it out.
>
> At the beginning, we need to trigger tx napi.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/net/virtio_net.c | 121 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 119 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 2767338dc060..7e811f392768 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -535,10 +535,13 @@ enum virtnet_xmit_type {
> VIRTNET_XMIT_TYPE_SKB,
> VIRTNET_XMIT_TYPE_XDP,
> VIRTNET_XMIT_TYPE_DMA,
> + VIRTNET_XMIT_TYPE_XSK,
> };
>
> #define VIRTNET_XMIT_TYPE_MASK (VIRTNET_XMIT_TYPE_SKB | VIRTNET_XMIT_TYPE_XDP \
> - | VIRTNET_XMIT_TYPE_DMA)
> + | VIRTNET_XMIT_TYPE_DMA | VIRTNET_XMIT_TYPE_XSK)
> +
> +#define VIRTIO_XSK_FLAG_OFFSET 4
>
> static enum virtnet_xmit_type virtnet_xmit_ptr_strip(void **ptr)
> {
> @@ -768,6 +771,10 @@ static void __free_old_xmit(struct send_queue *sq, bool in_napi,
> * func again.
> */
> goto retry;
> +
> + case VIRTNET_XMIT_TYPE_XSK:
> + /* Make gcc happy. DONE in subsequent commit */
This is probably a hint that the next patch should be squashed here.
> + break;
> }
> }
> }
> @@ -1265,6 +1272,102 @@ static void check_sq_full_and_disable(struct virtnet_info *vi,
> }
> }
>
> +static void *virtnet_xsk_to_ptr(u32 len)
> +{
> + unsigned long p;
> +
> + p = len << VIRTIO_XSK_FLAG_OFFSET;
> +
> + return virtnet_xmit_ptr_mix((void *)p, VIRTNET_XMIT_TYPE_XSK);
> +}
> +
> +static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
> +{
> + sg->dma_address = addr;
> + sg->length = len;
> +}
> +
> +static int virtnet_xsk_xmit_one(struct send_queue *sq,
> + struct xsk_buff_pool *pool,
> + struct xdp_desc *desc)
> +{
> + struct virtnet_info *vi;
> + dma_addr_t addr;
> +
> + vi = sq->vq->vdev->priv;
> +
> + addr = xsk_buff_raw_get_dma(pool, desc->addr);
> + xsk_buff_raw_dma_sync_for_device(pool, addr, desc->len);
> +
> + sg_init_table(sq->sg, 2);
> +
> + sg_fill_dma(sq->sg, sq->xsk.hdr_dma_address, vi->hdr_len);
> + sg_fill_dma(sq->sg + 1, addr, desc->len);
> +
> + return virtqueue_add_outbuf(sq->vq, sq->sg, 2,
> + virtnet_xsk_to_ptr(desc->len), GFP_ATOMIC);
> +}
> +
> +static int virtnet_xsk_xmit_batch(struct send_queue *sq,
> + struct xsk_buff_pool *pool,
> + unsigned int budget,
> + u64 *kicks)
> +{
> + struct xdp_desc *descs = pool->tx_descs;
> + bool kick = false;
> + u32 nb_pkts, i;
> + int err;
> +
> + budget = min_t(u32, budget, sq->vq->num_free);
> +
> + nb_pkts = xsk_tx_peek_release_desc_batch(pool, budget);
> + if (!nb_pkts)
> + return 0;
> +
> + for (i = 0; i < nb_pkts; i++) {
> + err = virtnet_xsk_xmit_one(sq, pool, &descs[i]);
> + if (unlikely(err)) {
> + xsk_tx_completed(sq->xsk.pool, nb_pkts - i);
> + break;
Any reason we don't need a kick here?
> + }
> +
> + kick = true;
> + }
> +
> + if (kick && virtqueue_kick_prepare(sq->vq) && virtqueue_notify(sq->vq))
> + (*kicks)++;
> +
> + return i;
> +}
> +
> +static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool,
> + int budget)
> +{
> + struct virtnet_info *vi = sq->vq->vdev->priv;
> + struct virtnet_sq_free_stats stats = {};
> + u64 kicks = 0;
> + int sent;
> +
> + __free_old_xmit(sq, true, &stats);
> +
> + sent = virtnet_xsk_xmit_batch(sq, pool, budget, &kicks);
> +
> + if (!is_xdp_raw_buffer_queue(vi, sq - vi->sq))
> + check_sq_full_and_disable(vi, vi->dev, sq);
> +
> + u64_stats_update_begin(&sq->stats.syncp);
> + u64_stats_add(&sq->stats.packets, stats.packets);
> + u64_stats_add(&sq->stats.bytes, stats.bytes);
> + u64_stats_add(&sq->stats.kicks, kicks);
> + u64_stats_add(&sq->stats.xdp_tx, sent);
> + u64_stats_update_end(&sq->stats.syncp);
> +
> + if (xsk_uses_need_wakeup(pool))
> + xsk_set_tx_need_wakeup(pool);
> +
> + return sent == budget;
> +}
> +
> static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
> struct send_queue *sq,
> struct xdp_frame *xdpf)
> @@ -2707,6 +2810,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
> struct virtnet_info *vi = sq->vq->vdev->priv;
> unsigned int index = vq2txq(sq->vq);
> struct netdev_queue *txq;
> + bool xsk_busy = false;
> int opaque;
> bool done;
>
> @@ -2719,7 +2823,11 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
> txq = netdev_get_tx_queue(vi->dev, index);
> __netif_tx_lock(txq, raw_smp_processor_id());
> virtqueue_disable_cb(sq->vq);
> - free_old_xmit(sq, true);
> +
> + if (sq->xsk.pool)
> + xsk_busy = virtnet_xsk_xmit(sq, sq->xsk.pool, budget);
How about rename this to "xsk_sent"?
> + else
> + free_old_xmit(sq, true);
>
> if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
> if (netif_tx_queue_stopped(txq)) {
> @@ -2730,6 +2838,11 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
> netif_tx_wake_queue(txq);
> }
>
> + if (xsk_busy) {
> + __netif_tx_unlock(txq);
> + return budget;
> + }
> +
> opaque = virtqueue_enable_cb_prepare(sq->vq);
>
> done = napi_complete_done(napi, 0);
> @@ -5715,6 +5828,10 @@ static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
> case VIRTNET_XMIT_TYPE_DMA:
> virtnet_sq_unmap(sq, &buf);
> goto retry;
> +
> + case VIRTNET_XMIT_TYPE_XSK:
> + /* Make gcc happy. DONE in subsequent commit */
> + break;
> }
> }
>
> --
> 2.32.0.3.g01195cf9f
>
Thanks
