On Mon, Oct 16, 2023 at 8:01 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> This patch implement the logic of bind/unbind xsk pool to sq and rq.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/net/virtio/Makefile | 2 +-
> drivers/net/virtio/main.c | 10 +-
> drivers/net/virtio/virtio_net.h | 18 ++++
> drivers/net/virtio/xsk.c | 186 ++++++++++++++++++++++++++++++++
> drivers/net/virtio/xsk.h | 7 ++
> 5 files changed, 216 insertions(+), 7 deletions(-)
> create mode 100644 drivers/net/virtio/xsk.c
> create mode 100644 drivers/net/virtio/xsk.h
>
> diff --git a/drivers/net/virtio/Makefile b/drivers/net/virtio/Makefile
> index 15ed7c97fd4f..8c2a884d2dba 100644
> --- a/drivers/net/virtio/Makefile
> +++ b/drivers/net/virtio/Makefile
> @@ -5,4 +5,4 @@
>
> obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
>
> -virtio_net-y := main.o
> +virtio_net-y := main.o xsk.o
> diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> index 02d27101fef1..38733a782f12 100644
> --- a/drivers/net/virtio/main.c
> +++ b/drivers/net/virtio/main.c
> @@ -8,7 +8,6 @@
> #include <linux/etherdevice.h>
> #include <linux/module.h>
> #include <linux/virtio.h>
> -#include <linux/virtio_net.h>
> #include <linux/bpf.h>
> #include <linux/bpf_trace.h>
> #include <linux/scatterlist.h>
> @@ -139,9 +138,6 @@ struct virtio_net_common_hdr {
> };
> };
>
> -static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
> -static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
> -
> static void *xdp_to_ptr(struct xdp_frame *ptr)
> {
> return (void *)((unsigned long)ptr | VIRTIO_XDP_FLAG);
> @@ -3664,6 +3660,8 @@ static int virtnet_xdp(struct net_device *dev, struct netdev_bpf *xdp)
> switch (xdp->command) {
> case XDP_SETUP_PROG:
> return virtnet_xdp_set(dev, xdp->prog, xdp->extack);
> + case XDP_SETUP_XSK_POOL:
> + return virtnet_xsk_pool_setup(dev, xdp);
> default:
> return -EINVAL;
> }
> @@ -3849,7 +3847,7 @@ static void free_receive_page_frags(struct virtnet_info *vi)
> }
> }
>
> -static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
> +void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
> {
> if (!virtnet_is_xdp_frame(buf))
> dev_kfree_skb(buf);
> @@ -3857,7 +3855,7 @@ static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
> xdp_return_frame(virtnet_ptr_to_xdp(buf));
> }
>
> -static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
> +void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
> {
> struct virtnet_info *vi = vq->vdev->priv;
> int i = vq2rxq(vq);
> diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> index cc742756e19a..9e69b6c5921b 100644
> --- a/drivers/net/virtio/virtio_net.h
> +++ b/drivers/net/virtio/virtio_net.h
> @@ -5,6 +5,8 @@
>
> #include <linux/ethtool.h>
> #include <linux/average.h>
> +#include <linux/virtio_net.h>
> +#include <net/xdp_sock_drv.h>
>
> #define VIRTIO_XDP_FLAG BIT(0)
> #define VIRTIO_XMIT_DATA_MASK (VIRTIO_XDP_FLAG)
> @@ -94,6 +96,11 @@ struct virtnet_sq {
> bool do_dma;
>
> struct virtnet_sq_dma_head dmainfo;
> + struct {
> + struct xsk_buff_pool __rcu *pool;
> +
> + dma_addr_t hdr_dma_address;
> + } xsk;
> };
>
> /* Internal representation of a receive virtqueue */
> @@ -134,6 +141,13 @@ struct virtnet_rq {
>
> /* Do dma by self */
> bool do_dma;
> +
> + struct {
> + struct xsk_buff_pool __rcu *pool;
> +
> + /* xdp rxq used by xsk */
> + struct xdp_rxq_info xdp_rxq;
> + } xsk;
> };
>
> struct virtnet_info {
> @@ -218,6 +232,8 @@ struct virtnet_info {
> struct failover *failover;
> };
>
> +#include "xsk.h"
> +
Any reason we don't do it with other headers?
> static inline bool virtnet_is_xdp_frame(void *ptr)
> {
> return (unsigned long)ptr & VIRTIO_XDP_FLAG;
> @@ -308,4 +324,6 @@ 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);
> void virtnet_tx_resume(struct virtnet_info *vi, struct virtnet_sq *sq);
> +void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
> +void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf);
> #endif
> diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> new file mode 100644
> index 000000000000..dddd01962a3f
> --- /dev/null
> +++ b/drivers/net/virtio/xsk.c
> @@ -0,0 +1,186 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * virtio-net xsk
> + */
> +
> +#include "virtio_net.h"
> +
> +static struct virtio_net_hdr_mrg_rxbuf xsk_hdr;
> +
> +static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *rq,
> + struct xsk_buff_pool *pool)
> +{
> + int err, qindex;
> +
> + qindex = rq - vi->rq;
> +
> + if (pool) {
> + err = xdp_rxq_info_reg(&rq->xsk.xdp_rxq, vi->dev, qindex, rq->napi.napi_id);
> + if (err < 0)
> + return err;
> +
> + err = xdp_rxq_info_reg_mem_model(&rq->xsk.xdp_rxq,
> + MEM_TYPE_XSK_BUFF_POOL, NULL);
> + if (err < 0) {
> + xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> + return err;
> + }
> +
> + xsk_pool_set_rxq_info(pool, &rq->xsk.xdp_rxq);
> + } else {
> + xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> + }
> +
> + virtnet_rx_pause(vi, rq);
> +
> + err = virtqueue_reset(rq->vq, virtnet_rq_free_unused_buf);
> + if (err)
> + netdev_err(vi->dev, "reset rx fail: rx queue index: %d err: %d\n", qindex, err);
> +
> + if (pool && err)
> + xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> + else
> + rcu_assign_pointer(rq->xsk.pool, pool);
> +
> + virtnet_rx_resume(vi, rq);
> +
> + return err;
> +}
> +
> +static int virtnet_sq_bind_xsk_pool(struct virtnet_info *vi,
> + struct virtnet_sq *sq,
> + struct xsk_buff_pool *pool)
> +{
> + int err, qindex;
> +
> + qindex = sq - vi->sq;
> +
> + virtnet_tx_pause(vi, sq);
> +
> + err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf);
> + if (err)
> + netdev_err(vi->dev, "reset tx fail: tx queue index: %d err: %d\n", qindex, err);
> +
> + if (pool) {
> + if (!err)
> + rcu_assign_pointer(sq->xsk.pool, pool);
> + } else {
> + rcu_assign_pointer(sq->xsk.pool, NULL);
> + }
> +
> + virtnet_tx_resume(vi, sq);
> +
> + return err;
> +}
> +
> +static int virtnet_xsk_pool_enable(struct net_device *dev,
> + struct xsk_buff_pool *pool,
> + u16 qid)
> +{
> + struct virtnet_info *vi = netdev_priv(dev);
> + struct virtnet_rq *rq;
> + struct virtnet_sq *sq;
> + struct device *dma_dev;
> + dma_addr_t hdr_dma;
> + int err;
> +
> + /* In big_packets mode, xdp cannot work, so there is no need to
> + * initialize xsk of rq.
> + */
> + if (vi->big_packets && !vi->mergeable_rx_bufs)
> + return -ENOENT;
> +
> + if (qid >= vi->curr_queue_pairs)
> + return -EINVAL;
> +
> + sq = &vi->sq[qid];
> + rq = &vi->rq[qid];
> +
> + /* xsk tx zerocopy depend on the tx napi.
> + *
> + * All xsk packets are actually consumed and sent out from the xsk tx
> + * queue under the tx napi mechanism.
> + */
> + if (!sq->napi.weight)
> + return -EPERM;
> +
> + if (!rq->do_dma || !sq->do_dma)
> + return -EPERM;
> +
> + if (virtqueue_dma_dev(rq->vq) != virtqueue_dma_dev(sq->vq))
> + return -EPERM;
Any reason we need this check? Is there any code that has this
assumption? E.g dma sync in XDP_TX?
> +
> + dma_dev = virtqueue_dma_dev(rq->vq);
> + if (!dma_dev)
> + return -EPERM;
> +
> + hdr_dma = dma_map_single(dma_dev, &xsk_hdr, vi->hdr_len, DMA_TO_DEVICE);
> + if (dma_mapping_error(dma_dev, hdr_dma))
> + return -ENOMEM;
> +
> + err = xsk_pool_dma_map(pool, dma_dev, 0);
> + if (err)
> + goto err_xsk_map;
> +
> + err = virtnet_rq_bind_xsk_pool(vi, rq, pool);
> + if (err)
> + goto err_rq;
> +
> + err = virtnet_sq_bind_xsk_pool(vi, sq, pool);
> + if (err)
> + goto err_sq;
> +
> + sq->xsk.hdr_dma_address = hdr_dma;
I think we probably need some comments to explain why a single hdr can
work. Like it means we use the same hdr for all XSK packets?
> +
> + return 0;
> +
> +err_sq:
> + virtnet_rq_bind_xsk_pool(vi, rq, NULL);
> +err_rq:
> + xsk_pool_dma_unmap(pool, 0);
> +err_xsk_map:
> + dma_unmap_single(dma_dev, hdr_dma, vi->hdr_len, DMA_TO_DEVICE);
> + return err;
> +}
> +
> +static int virtnet_xsk_pool_disable(struct net_device *dev, u16 qid)
> +{
> + struct virtnet_info *vi = netdev_priv(dev);
> + struct xsk_buff_pool *pool;
> + struct device *dma_dev;
> + struct virtnet_rq *rq;
> + struct virtnet_sq *sq;
> + int err1, err2;
> +
> + if (qid >= vi->curr_queue_pairs)
> + return -EINVAL;
> +
> + sq = &vi->sq[qid];
> + rq = &vi->rq[qid];
> +
> + dma_dev = virtqueue_dma_dev(rq->vq);
> +
> + /* Sync with the XSK wakeup and NAPI. */
> + synchronize_net();
Any reason we couldn't do bind_xsk_pool(NULL) here? It seems easier.
Thanks
> +
> + dma_unmap_single(dma_dev, sq->xsk.hdr_dma_address, vi->hdr_len, DMA_TO_DEVICE);
> +
> + rcu_read_lock();
> + pool = rcu_dereference(sq->xsk.pool);
> + xsk_pool_dma_unmap(pool, 0);
> + rcu_read_unlock();
> +
> + err1 = virtnet_sq_bind_xsk_pool(vi, sq, NULL);
> + err2 = virtnet_rq_bind_xsk_pool(vi, rq, NULL);
> +
> + return err1 | err2;
> +}
> +
> +int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp)
> +{
> + if (xdp->xsk.pool)
> + return virtnet_xsk_pool_enable(dev, xdp->xsk.pool,
> + xdp->xsk.queue_id);
> + else
> + return virtnet_xsk_pool_disable(dev, xdp->xsk.queue_id);
> +}
> diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h
> new file mode 100644
> index 000000000000..1918285c310c
> --- /dev/null
> +++ b/drivers/net/virtio/xsk.h
> @@ -0,0 +1,7 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +#ifndef __XSK_H__
> +#define __XSK_H__
> +
> +int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp);
> +#endif
> --
> 2.32.0.3.g01195cf9f
>
