On Fri, 20 Oct 2023 14:51:15 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> 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?
Because xsk.h will reference the struct virtnet_sq..., if we put xsk.h
at the start of virtio_net.h, the gcc will not happy.
But the virtio-net.h references the api(virtnet_ptr_to_xsk) of the xsk.h.
>
> > 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 @@
[...]
> > +
> > + 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?
For the xsk, the tx and rx should have the same dev.
But vq->dma_dev allows every vq has the respective dma dev.
So I check the dma dev of vq and sq is the same dev.
>
> > +
> > + 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?
Will fix.
>
> > +
> > + 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.
Do you mean rcu_assign_pointer() is enough?
Let me check it.
Thanks
>
> 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
> >
>
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