virtio_net: setup xdp_rxq_info

The virtio_net driver doesn't dynamically change the RX-ring queue
layout and backing pages, but instead reject XDP setup if all the
conditions for XDP is not meet.  Thus, the xdp_rxq_info also remains
fairly static.  This allow us to simply add the reg/unreg to
net_device open/close functions.

Driver hook points for xdp_rxq_info:
 * reg  : virtnet_open
 * unreg: virtnet_close

V3:
 - bugfix, also setup xdp.rxq in receive_mergeable()
 - Tested bpf-sample prog inside guest on a virtio_net device

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 6fb7b658a6cc7b67a7f719e3f48e36cc1cb64bde..ed8299343728bb2826d70375d3d0c9741b3e3c72 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -31,6 +31,7 @@
 #include <linux/average.h>
 #include <linux/filter.h>
 #include <net/route.h>
+#include <net/xdp.h>
 
 static int napi_weight = NAPI_POLL_WEIGHT;
 module_param(napi_weight, int, 0444);
@@ -115,6 +116,8 @@ struct receive_queue {
 
        /* Name of this receive queue: input.$index */
        char name[40];
+
+       struct xdp_rxq_info xdp_rxq;
 };
 
 struct virtnet_info {
@@ -559,6 +562,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
                xdp.data = xdp.data_hard_start + xdp_headroom;
                xdp_set_data_meta_invalid(&xdp);
                xdp.data_end = xdp.data + len;
+               xdp.rxq = &rq->xdp_rxq;
                orig_data = xdp.data;
                act = bpf_prog_run_xdp(xdp_prog, &xdp);
 
@@ -692,6 +696,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                xdp.data = data + vi->hdr_len;
                xdp_set_data_meta_invalid(&xdp);
                xdp.data_end = xdp.data + (len - vi->hdr_len);
+               xdp.rxq = &rq->xdp_rxq;
+
                act = bpf_prog_run_xdp(xdp_prog, &xdp);
 
                if (act != XDP_PASS)
@@ -1225,13 +1231,18 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
 static int virtnet_open(struct net_device *dev)
 {
        struct virtnet_info *vi = netdev_priv(dev);
-       int i;
+       int i, err;
 
        for (i = 0; i < vi->max_queue_pairs; i++) {
                if (i < vi->curr_queue_pairs)
                        /* Make sure we have some buffers: if oom use wq. */
                        if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
                                schedule_delayed_work(&vi->refill, 0);
+
+               err = xdp_rxq_info_reg(&vi->rq[i].xdp_rxq, dev, i);
+               if (err < 0)
+                       return err;
+
                virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
                virtnet_napi_tx_enable(vi, vi->sq[i].vq, &vi->sq[i].napi);
        }
@@ -1560,6 +1571,7 @@ static int virtnet_close(struct net_device *dev)
        cancel_delayed_work_sync(&vi->refill);
 
        for (i = 0; i < vi->max_queue_pairs; i++) {
+               xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
                napi_disable(&vi->rq[i].napi);
                virtnet_napi_tx_disable(&vi->sq[i].napi);
        }