[net-next RFC V5 5/5] virtio_net: support negotiating the number of queues through ctrl vq

@@ -88,6 +88,7 @@ struct receive_queue {
 
 struct virtnet_info {
 	u16 num_queue_pairs;		/* # of RX/TX vq pairs */
+	u16 total_queue_pairs;
 
 	struct send_queue *sq[MAX_QUEUES] ____cacheline_aligned_in_smp;
 	struct receive_queue *rq[MAX_QUEUES] ____cacheline_aligned_in_smp;

@@ -137,6 +138,8 @@ struct padded_vnet_hdr {
 	char padding[6];
 };
 
+static const struct ethtool_ops virtnet_ethtool_ops;
+
 static inline int txq_get_qnum(struct virtnet_info *vi, struct virtqueue *vq)
 {
 	int ret = virtqueue_get_queue_index(vq);

@@ -802,22 +805,6 @@ static void virtnet_netpoll(struct net_device *dev)
 }
 #endif
 
-static int virtnet_open(struct net_device *dev)
-{
-	struct virtnet_info *vi = netdev_priv(dev);
-	int i;
-
-	for (i = 0; i < vi->num_queue_pairs; i++) {
-		/* Make sure we have some buffers: if oom use wq. */
-		if (!try_fill_recv(vi->rq[i], GFP_KERNEL))
-			queue_delayed_work(system_nrt_wq,
-					   &vi->rq[i]->refill, 0);
-		virtnet_napi_enable(vi->rq[i]);
-	}
-
-	return 0;
-}
-
 /*
  * Send command via the control virtqueue and check status.  Commands
  * supported by the hypervisor, as indicated by feature bits, should

@@ -873,6 +860,43 @@ static void virtnet_ack_link_announce(struct virtnet_info *vi)
 	rtnl_unlock();
 }
 
+static int virtnet_set_queues(struct virtnet_info *vi)
+{
+	struct scatterlist sg;
+	struct net_device *dev = vi->dev;
+	sg_init_one(&sg, &vi->num_queue_pairs, sizeof(vi->num_queue_pairs));
+
+	if (!vi->has_cvq)
+		return -EINVAL;
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MULTIQUEUE,
+				  VIRTIO_NET_CTRL_MULTIQUEUE_QNUM, &sg, 1, 0)){
+		dev_warn(&dev->dev, "Fail to set the number of queue pairs to"
+			 " %d\n", vi->num_queue_pairs);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int virtnet_open(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int i;
+
+	for (i = 0; i < vi->num_queue_pairs; i++) {
+		/* Make sure we have some buffers: if oom use wq. */
+		if (!try_fill_recv(vi->rq[i], GFP_KERNEL))
+			queue_delayed_work(system_nrt_wq,
+					   &vi->rq[i]->refill, 0);
+		virtnet_napi_enable(vi->rq[i]);
+	}
+
+	virtnet_set_queues(vi);
+
+	return 0;
+}
+
 static int virtnet_close(struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);

@@ -1013,12 +1037,6 @@ static void virtnet_get_drvinfo(struct net_device *dev,
 
 }
 
-static const struct ethtool_ops virtnet_ethtool_ops = {
-	.get_drvinfo = virtnet_get_drvinfo,
-	.get_link = ethtool_op_get_link,
-	.get_ringparam = virtnet_get_ringparam,
-};
-
 #define MIN_MTU 68
 #define MAX_MTU 65535
 

@@ -1235,7 +1253,7 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
 
 err:
 	if (ret && names)
-		for (i = 0; i < vi->num_queue_pairs * 2; i++)
+		for (i = 0; i < total_vqs * 2; i++)
 			kfree(names[i]);
 
 	kfree(names);

@@ -1373,7 +1391,6 @@ static int virtnet_probe(struct virtio_device *vdev)
 	mutex_init(&vi->config_lock);
 	vi->config_enable = true;
 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
-	vi->num_queue_pairs = num_queue_pairs;
 
 	/* If we can receive ANY GSO packets, we must allocate large ones. */
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||

@@ -1387,6 +1404,10 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
 		vi->has_cvq = true;
 
+	/* Use single tx/rx queue pair as default */
+	vi->num_queue_pairs = 1;
+	vi->total_queue_pairs = num_queue_pairs;
+
 	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
 	err = virtnet_setup_vqs(vi);
 	if (err)

@@ -1396,6 +1417,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 	    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
 		dev->features |= NETIF_F_HW_VLAN_FILTER;
 
+	netif_set_real_num_tx_queues(dev, 1);
+	netif_set_real_num_rx_queues(dev, 1);
+
 	err = register_netdev(dev);
 	if (err) {
 		pr_debug("virtio_net: registering device failed\n");

@@ -1403,7 +1427,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 	}
 
 	/* Last of all, set up some receive buffers. */
-	for (i = 0; i < num_queue_pairs; i++) {
+	for (i = 0; i < vi->num_queue_pairs; i++) {
 		try_fill_recv(vi->rq[i], GFP_KERNEL);
 
 		/* If we didn't even get one input buffer, we're useless. */

@@ -1474,10 +1498,8 @@ static void __devexit virtnet_remove(struct virtio_device *vdev)
 	free_netdev(vi->dev);
 }
 
-#ifdef CONFIG_PM
-static int virtnet_freeze(struct virtio_device *vdev)
+static void virtnet_stop(struct virtnet_info *vi)
 {
-	struct virtnet_info *vi = vdev->priv;
 	int i;
 
 	/* Prevent config work handler from accessing the device */

@@ -1493,17 +1515,10 @@ static int virtnet_freeze(struct virtio_device *vdev)
 		for (i = 0; i < vi->num_queue_pairs; i++)
 			napi_disable(&vi->rq[i]->napi);
 
-
-	remove_vq_common(vi);
-
-	flush_work(&vi->config_work);
-
-	return 0;
 }
 
-static int virtnet_restore(struct virtio_device *vdev)
+static int virtnet_start(struct virtnet_info *vi)
 {
-	struct virtnet_info *vi = vdev->priv;
 	int err, i;
 
 	err = virtnet_setup_vqs(vi);

@@ -1527,6 +1542,29 @@ static int virtnet_restore(struct virtio_device *vdev)
 
 	return 0;
 }
+
+#ifdef CONFIG_PM
+static int virtnet_freeze(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+
+	virtnet_stop(vi);
+
+	remove_vq_common(vi);
+
+	flush_work(&vi->config_work);
+
+	return 0;
+}
+
+static int virtnet_restore(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+
+	virtnet_start(vi);
+
+	return 0;
+}
 #endif
 
 static struct virtio_device_id id_table[] = {

@@ -1560,6 +1598,67 @@ static struct virtio_driver virtio_net_driver = {
 #endif
 };
 
+static int virtnet_set_channels(struct net_device *dev,
+				struct ethtool_channels *channels)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	u16 queues = channels->rx_count;
+	unsigned status = VIRTIO_CONFIG_S_ACKNOWLEDGE | VIRTIO_CONFIG_S_DRIVER;
+
+	if (channels->rx_count != channels->tx_count)
+		return -EINVAL;
+	/* Only two modes were support currently */
+	if (queues != vi->total_queue_pairs && queues != 1)
+		return -EINVAL;
+	if (!vi->has_cvq)
+		return -EINVAL;
+
+	virtnet_stop(vi);
+
+	netif_set_real_num_tx_queues(dev, queues);
+	netif_set_real_num_rx_queues(dev, queues);
+
+	remove_vq_common(vi);
+	flush_work(&vi->config_work);
+
+	vi->num_queue_pairs = queues;
+	virtnet_start(vi);
+
+	vi->vdev->config->finalize_features(vi->vdev);
+
+	if (virtnet_set_queues(vi))
+		status |= VIRTIO_CONFIG_S_FAILED;
+	else
+		status |= VIRTIO_CONFIG_S_DRIVER_OK;
+
+	vi->vdev->config->set_status(vi->vdev, status);
+
+	return 0;
+}
+
+static void virtnet_get_channels(struct net_device *dev,
+				 struct ethtool_channels *channels)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+
+	channels->max_rx = vi->total_queue_pairs;
+	channels->max_tx = vi->total_queue_pairs;
+	channels->max_other = 0;
+	channels->max_combined = 0;
+	channels->rx_count = vi->num_queue_pairs;
+	channels->tx_count = vi->num_queue_pairs;
+	channels->other_count = 0;
+	channels->combined_count = 0;
+}
+
+static const struct ethtool_ops virtnet_ethtool_ops = {
+	.get_drvinfo = virtnet_get_drvinfo,
+	.get_link = ethtool_op_get_link,
+	.get_ringparam = virtnet_get_ringparam,
+	.set_channels = virtnet_set_channels,
+	.get_channels = virtnet_get_channels,
+};
+
 static int __init init(void)
 {
 	return register_virtio_driver(&virtio_net_driver);

@@ -169,4 +169,11 @@ struct virtio_net_ctrl_mac {
 #define VIRTIO_NET_CTRL_ANNOUNCE       3
  #define VIRTIO_NET_CTRL_ANNOUNCE_ACK         0
 
+/*
+ * Control multiqueue
+ *
+ */
+#define VIRTIO_NET_CTRL_MULTIQUEUE       4
+ #define VIRTIO_NET_CTRL_MULTIQUEUE_QNUM         0
+
 #endif /* _LINUX_VIRTIO_NET_H */