virtio_net: add ethtool support for set and get of settings

This patch allows the user to set and retrieve speed and duplex of the
virtio_net device via ethtool. Having this functionality is very helpful
for simulating different environments and also enables the virtio_net
device to participate in operations where proper speed and duplex are
required (e.g. currently bonding lacp mode requires full duplex). Custom
speed and duplex are not allowed, the user-supplied settings are validated
before applying.

Example:
$ ethtool eth1
Settings for eth1:
...
	Speed: Unknown!
	Duplex: Unknown! (255)
$ ethtool -s eth1 speed 1000 duplex full
$ ethtool eth1
Settings for eth1:
...
	Speed: 1000Mb/s
	Duplex: Full

Based on a patch by Roopa Prabhu.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 767ab11a6e9f67ce774d086101daeb1eb91838ce..c9fd52a8e6ec5f05d3459ba26994a449df764ec6 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -146,6 +146,10 @@ struct virtnet_info {
        virtio_net_ctrl_ack ctrl_status;
        u8 ctrl_promisc;
        u8 ctrl_allmulti;
+
+       /* Ethtool settings */
+       u8 duplex;
+       u32 speed;
 };
 
 struct padded_vnet_hdr {
@@ -1376,6 +1380,58 @@ static void virtnet_get_channels(struct net_device *dev,
        channels->other_count = 0;
 }
 
+/* Check if the user is trying to change anything besides speed/duplex */
+static bool virtnet_validate_ethtool_cmd(const struct ethtool_cmd *cmd)
+{
+       struct ethtool_cmd diff1 = *cmd;
+       struct ethtool_cmd diff2 = {};
+
+       /* advertising and cmd are usually set, ignore port because we set it */
+       ethtool_cmd_speed_set(&diff1, 0);
+       diff1.advertising = 0;
+       diff1.duplex = 0;
+       diff1.port = 0;
+       diff1.cmd = 0;
+
+       return !memcmp(&diff1, &diff2, sizeof(diff1));
+}
+
+static int virtnet_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+       struct virtnet_info *vi = netdev_priv(dev);
+       u32 speed;
+
+       speed = ethtool_cmd_speed(cmd);
+       /* don't allow custom speed and duplex */
+       if (!ethtool_validate_speed(speed) ||
+           !ethtool_validate_duplex(cmd->duplex) ||
+           !virtnet_validate_ethtool_cmd(cmd))
+               return -EINVAL;
+       vi->speed = speed;
+       vi->duplex = cmd->duplex;
+
+       return 0;
+}
+
+static int virtnet_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+       struct virtnet_info *vi = netdev_priv(dev);
+
+       ethtool_cmd_speed_set(cmd, vi->speed);
+       cmd->duplex = vi->duplex;
+       cmd->port = PORT_OTHER;
+
+       return 0;
+}
+
+static void virtnet_init_settings(struct net_device *dev)
+{
+       struct virtnet_info *vi = netdev_priv(dev);
+
+       vi->speed = SPEED_UNKNOWN;
+       vi->duplex = DUPLEX_UNKNOWN;
+}
+
 static const struct ethtool_ops virtnet_ethtool_ops = {
        .get_drvinfo = virtnet_get_drvinfo,
        .get_link = ethtool_op_get_link,
@@ -1383,6 +1439,8 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
        .set_channels = virtnet_set_channels,
        .get_channels = virtnet_get_channels,
        .get_ts_info = ethtool_op_get_ts_info,
+       .get_settings = virtnet_get_settings,
+       .set_settings = virtnet_set_settings,
 };
 
 #define MIN_MTU 68
@@ -1855,6 +1913,8 @@ static int virtnet_probe(struct virtio_device *vdev)
        netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
        netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
 
+       virtnet_init_settings(dev);
+
        err = register_netdev(dev);
        if (err) {
                pr_debug("virtio_net: registering device failed\n");