@@ -114,6 +114,9 @@ struct virtnet_info {
/* # of queue pairs currently used by the driver */
u16 curr_queue_pairs;
+ /* # of XDP queue pairs currently used by the driver */
+ u16 xdp_queue_pairs;
+
/* I like... big packets and I cannot lie! */
bool big_packets;
@@ -1533,7 +1536,8 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
{
struct virtnet_info *vi = netdev_priv(dev);
struct bpf_prog *old_prog;
- int i;
+ u16 xdp_qp = 0, curr_qp;
+ int err, i;
if ((dev->features & NETIF_F_LRO) && prog) {
netdev_warn(dev, "can't set XDP while LRO is on, disable LRO first\n");
@@ -1550,12 +1554,34 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
return -EINVAL;
}
+ curr_qp = vi->curr_queue_pairs - vi->xdp_queue_pairs;
+ if (prog)
+ xdp_qp = nr_cpu_ids;
+
+ /* XDP requires extra queues for XDP_TX */
+ if (curr_qp + xdp_qp > vi->max_queue_pairs) {
+ netdev_warn(dev, "request %i queues but max is %i\n",
+ curr_qp + xdp_qp, vi->max_queue_pairs);
+ return -ENOMEM;
+ }
+
+ err = virtnet_set_queues(vi, curr_qp + xdp_qp);
+ if (err) {
+ dev_warn(&dev->dev, "XDP Device queue allocation failure.\n");
+ return err;
+ }
+
if (prog) {
prog = bpf_prog_add(prog, vi->max_queue_pairs - 1);
- if (IS_ERR(prog))
+ if (IS_ERR(prog)) {
+ virtnet_set_queues(vi, curr_qp);
return PTR_ERR(prog);
+ }
}
+ vi->xdp_queue_pairs = xdp_qp;
+ netif_set_real_num_rx_queues(dev, curr_qp + xdp_qp);
+
for (i = 0; i < vi->max_queue_pairs; i++) {
old_prog = rtnl_dereference(vi->rq[i].xdp_prog);
rcu_assign_pointer(vi->rq[i].xdp_prog, prog);
XDP requires using isolated transmit queues to avoid interference with normal networking stack (BQL, NETDEV_TX_BUSY, etc). This patch adds a XDP queue per cpu when a XDP program is loaded and does not expose the queues to the OS via the normal API call to netif_set_real_num_tx_queues(). This way the stack will never push an skb to these queues. However virtio/vhost/qemu implementation only allows for creating TX/RX queue pairs at this time so creating only TX queues was not possible. And because the associated RX queues are being created I went ahead and exposed these to the stack and let the backend use them. This creates more RX queues visible to the network stack than TX queues which is worth mentioning but does not cause any issues as far as I can tell. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> --- drivers/net/virtio_net.c | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-)