From: Nikolay Aleksandrov <niko...@cumulusnetworks.com>

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. Only full and unknown duplex are allowed to be set.

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.

CC: Roopa Prabhu <ro...@cumulusnetworks.com>
CC: Michael S. Tsirkin <m...@redhat.com>
CC: virtualizat...@lists.linux-foundation.org
Signed-off-by: Nikolay Aleksandrov <niko...@cumulusnetworks.com>
---
Allowed to set unknown speed/duplex if the user wants to reset them, though
the user-space ethtool tool currently doesn't allow setting them.

 drivers/net/virtio_net.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 767ab11a6e9f..722ade567ee5 100644
--- 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 +1380,72 @@ static void virtnet_get_channels(struct net_device *dev,
        channels->other_count = 0;
 }
 
+static bool virtnet_validate_speed(u32 speed)
+{
+       switch (speed) {
+       case SPEED_10:
+       case SPEED_100:
+       case SPEED_1000:
+       case SPEED_2500:
+       case SPEED_5000:
+       case SPEED_10000:
+       case SPEED_20000:
+       case SPEED_25000:
+       case SPEED_40000:
+       case SPEED_50000:
+       case SPEED_56000:
+       case SPEED_100000:
+       case SPEED_UNKNOWN:
+               return true;
+       }
+
+       return false;
+}
+
+static bool virtnet_validate_duplex(u8 duplex)
+{
+       switch (duplex) {
+       case DUPLEX_FULL:
+       case DUPLEX_UNKNOWN:
+               return true;
+       }
+
+       return false;
+}
+
+static int virtnet_set_settings(struct net_device *dev, struct ethtool_cmd 
*cmd)
+{
+       struct virtnet_info *vi = netdev_priv(dev);
+       u32 speed = ethtool_cmd_speed(cmd);
+
+       /* don't allow custom speed and duplex */
+       if (!virtnet_validate_speed(speed) ||
+           !virtnet_validate_duplex(cmd->duplex))
+               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;
+
+       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 +1453,8 @@ 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 +1927,8 @@ 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");
-- 
2.4.3

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