This patch implement the logic of bind/unbind xsk pool to rq.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---

v7:
    1. remove a container struct for xsk
    2. update comments
    3. add check between hdr_len and xsk headroom

 drivers/net/virtio_net.c | 134 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 3c828cdd438b..cd87b39600d4 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -25,6 +25,7 @@
 #include <net/net_failover.h>
 #include <net/netdev_rx_queue.h>
 #include <net/netdev_queues.h>
+#include <net/xdp_sock_drv.h>

 static int napi_weight = NAPI_POLL_WEIGHT;
 module_param(napi_weight, int, 0444);

@@ -348,6 +349,11 @@ struct receive_queue {

        /* Record the last dma info to free after new pages is allocated. */
        struct virtnet_rq_dma *last_dma;
+
+       struct xsk_buff_pool *xsk_pool;
+
+       /* xdp rxq used by xsk */
+       struct xdp_rxq_info xsk_rxq_info;
 };

 /* This structure can contain rss message with maximum settings for indirection table and keysize

@@ -5026,6 +5032,132 @@ static int virtnet_restore_guest_offloads(struct virtnet_info *vi)
        return virtnet_set_guest_offloads(vi, offloads);
 }

+static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct receive_queue *rq,
+                                   struct xsk_buff_pool *pool)
+{
+       int err, qindex;
+
+       qindex = rq - vi->rq;
+
+       if (pool) {
+               err = xdp_rxq_info_reg(&rq->xsk_rxq_info, vi->dev, qindex, rq->napi.napi_id);
+               if (err < 0)
+                       return err;
+
+               err = xdp_rxq_info_reg_mem_model(&rq->xsk_rxq_info,
+                                                MEM_TYPE_XSK_BUFF_POOL, NULL);
+               if (err < 0)
+                       goto unreg;
+
+               xsk_pool_set_rxq_info(pool, &rq->xsk_rxq_info);
+       }
+
+       virtnet_rx_pause(vi, rq);
+
+       err = virtqueue_reset(rq->vq, virtnet_rq_unmap_free_buf);
+       if (err) {
+               netdev_err(vi->dev, "reset rx fail: rx queue index: %d err: %d\n", qindex, err);
+
+               pool = NULL;
+       }
+
+       rq->xsk_pool = pool;
+
+       virtnet_rx_resume(vi, rq);
+
+       if (pool)
+               return 0;
+
+unreg:
+       xdp_rxq_info_unreg(&rq->xsk_rxq_info);
+       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 receive_queue *rq;
+       struct device *dma_dev;
+       struct send_queue *sq;
+       int err;
+
+       if (vi->hdr_len > xsk_pool_get_headroom(pool))
+               return -EINVAL;
+
+       /* 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 assumes that tx and rx must have the same dma device. The af-xdp
+        * may use one buffer to receive from the rx and reuse this buffer to
+        * send by the tx. So the dma dev of sq and rq must be the same one.
+        *
+        * 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.
+        */
+       if (virtqueue_dma_dev(rq->vq) != virtqueue_dma_dev(sq->vq))
+               return -EPERM;