On Fri, 20 Oct 2023 14:56:51 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> On Mon, Oct 16, 2023 at 8:01 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
> >
> > Implement the logic of filling vq with XSK buffer.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > ---
> > drivers/net/virtio/main.c | 13 +++++++
> > drivers/net/virtio/virtio_net.h | 5 +++
> > drivers/net/virtio/xsk.c | 66 ++++++++++++++++++++++++++++++++-
> > drivers/net/virtio/xsk.h | 2 +
> > 4 files changed, 85 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> > index 58bb38f9b453..0e740447b142 100644
> > --- a/drivers/net/virtio/main.c
> > +++ b/drivers/net/virtio/main.c
> > @@ -1787,9 +1787,20 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
> > static bool try_fill_recv(struct virtnet_info *vi, struct virtnet_rq *rq,
> > gfp_t gfp)
> > {
> > + struct xsk_buff_pool *pool;
> > int err;
> > bool oom;
> >
> > + rcu_read_lock();
>
> A question here: should we sync with refill work during rx_pause?
>
> > + pool = rcu_dereference(rq->xsk.pool);
> > + if (pool) {
> > + err = virtnet_add_recvbuf_xsk(vi, rq, pool, gfp);
> > + oom = err == -ENOMEM;
> > + rcu_read_unlock();
> > + goto kick;
> > + }
> > + rcu_read_unlock();
>
> And if we synchronize with that there's probably no need for the rcu
> and we can merge the logic with the following ones?
YES. we synchronize the rx_pause and this.
But for the rcu object, I think we should use rcu_xxx() API.
Thanks.
>
> Thanks
>
>
> > +
> > do {
> > if (vi->mergeable_rx_bufs)
> > err = add_recvbuf_mergeable(vi, rq, gfp);
> > @@ -1802,6 +1813,8 @@ static bool try_fill_recv(struct virtnet_info *vi, struct virtnet_rq *rq,
> > if (err)
> > break;
> > } while (rq->vq->num_free);
> > +
> > +kick:
> > if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
> > unsigned long flags;
> >
> > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> > index d4e620a084f4..6e71622fca45 100644
> > --- a/drivers/net/virtio/virtio_net.h
> > +++ b/drivers/net/virtio/virtio_net.h
> > @@ -156,6 +156,11 @@ struct virtnet_rq {
> >
> > /* xdp rxq used by xsk */
> > struct xdp_rxq_info xdp_rxq;
> > +
> > + struct xdp_buff **xsk_buffs;
> > + u32 nxt_idx;
> > + u32 num;
> > + u32 size;
> > } xsk;
> > };
> >
> > diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> > index 973e783260c3..841fb078882a 100644
> > --- a/drivers/net/virtio/xsk.c
> > +++ b/drivers/net/virtio/xsk.c
> > @@ -37,6 +37,58 @@ static void virtnet_xsk_check_queue(struct virtnet_sq *sq)
> > netif_stop_subqueue(dev, qnum);
> > }
> >
> > +static int virtnet_add_recvbuf_batch(struct virtnet_info *vi, struct virtnet_rq *rq,
> > + struct xsk_buff_pool *pool, gfp_t gfp)
> > +{
> > + struct xdp_buff **xsk_buffs;
> > + dma_addr_t addr;
> > + u32 len, i;
> > + int err = 0;
> > +
> > + xsk_buffs = rq->xsk.xsk_buffs;
> > +
> > + if (rq->xsk.nxt_idx >= rq->xsk.num) {
> > + rq->xsk.num = xsk_buff_alloc_batch(pool, xsk_buffs, rq->xsk.size);
> > + if (!rq->xsk.num)
> > + return -ENOMEM;
> > + rq->xsk.nxt_idx = 0;
> > + }
> > +
> > + while (rq->xsk.nxt_idx < rq->xsk.num) {
> > + i = rq->xsk.nxt_idx;
> > +
> > + /* use the part of XDP_PACKET_HEADROOM as the virtnet hdr space */
> > + addr = xsk_buff_xdp_get_dma(xsk_buffs[i]) - vi->hdr_len;
> > + len = xsk_pool_get_rx_frame_size(pool) + vi->hdr_len;
> > +
> > + sg_init_table(rq->sg, 1);
> > + sg_fill_dma(rq->sg, addr, len);
> > +
> > + err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, xsk_buffs[i], gfp);
> > + if (err)
> > + return err;
> > +
> > + rq->xsk.nxt_idx++;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct virtnet_rq *rq,
> > + struct xsk_buff_pool *pool, gfp_t gfp)
> > +{
> > + int err;
> > +
> > + do {
> > + err = virtnet_add_recvbuf_batch(vi, rq, pool, gfp);
> > + if (err)
> > + return err;
> > +
> > + } while (rq->vq->num_free);
> > +
> > + return 0;
> > +}
> > +
> > static int virtnet_xsk_xmit_one(struct virtnet_sq *sq,
> > struct xsk_buff_pool *pool,
> > struct xdp_desc *desc)
> > @@ -244,7 +296,7 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
> > struct virtnet_sq *sq;
> > struct device *dma_dev;
> > dma_addr_t hdr_dma;
> > - int err;
> > + int err, size;
> >
> > /* In big_packets mode, xdp cannot work, so there is no need to
> > * initialize xsk of rq.
> > @@ -276,6 +328,16 @@ static int virtnet_xsk_pool_enable(struct net_device *dev,
> > if (!dma_dev)
> > return -EPERM;
> >
> > + size = virtqueue_get_vring_size(rq->vq);
> > +
> > + rq->xsk.xsk_buffs = kcalloc(size, sizeof(*rq->xsk.xsk_buffs), GFP_KERNEL);
> > + if (!rq->xsk.xsk_buffs)
> > + return -ENOMEM;
> > +
> > + rq->xsk.size = size;
> > + rq->xsk.nxt_idx = 0;
> > + rq->xsk.num = 0;
> > +
> > 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;
> > @@ -338,6 +400,8 @@ static int virtnet_xsk_pool_disable(struct net_device *dev, u16 qid)
> > err1 = virtnet_sq_bind_xsk_pool(vi, sq, NULL);
> > err2 = virtnet_rq_bind_xsk_pool(vi, rq, NULL);
> >
> > + kfree(rq->xsk.xsk_buffs);
> > +
> > return err1 | err2;
> > }
> >
> > diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h
> > index 7ebc9bda7aee..bef41a3f954e 100644
> > --- a/drivers/net/virtio/xsk.h
> > +++ b/drivers/net/virtio/xsk.h
> > @@ -23,4 +23,6 @@ int virtnet_xsk_pool_setup(struct net_device *dev, struct netdev_bpf *xdp);
> > bool virtnet_xsk_xmit(struct virtnet_sq *sq, struct xsk_buff_pool *pool,
> > int budget);
> > 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);
> > #endif
> > --
> > 2.32.0.3.g01195cf9f
> >
>
