virtio-net: introduce a new control to set macaddr

Currently we write MAC address to pci config space byte by byte,
this means that we have an intermediate step where mac is wrong.
This patch introduced a new control command to set MAC address,
it's atomic.

VIRTIO_NET_F_CTRL_MAC_ADDR is a new feature bit for compatibility.

Signed-off-by: Amos Kong <akong@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 3 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 395ab4ff3e64..701408a1ded6 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -802,14 +802,28 @@ static int virtnet_set_mac_address(struct net_device *dev, void *p)
         struct virtnet_info *vi = netdev_priv(dev);
         struct virtio_device *vdev = vi->vdev;
         int ret;
+        struct sockaddr *addr = p;
+        struct scatterlist sg;
 
-        ret = eth_mac_addr(dev, p);
+        ret = eth_prepare_mac_addr_change(dev, p);
         if (ret)
                 return ret;
 
-        if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
+        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
+                sg_init_one(&sg, addr->sa_data, dev->addr_len);
+                if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
+                                          VIRTIO_NET_CTRL_MAC_ADDR_SET,
+                                          &sg, 1, 0)) {
+                        dev_warn(&vdev->dev,
+                                 "Failed to set mac address by vq command.\n");
+                        return -EINVAL;
+                }
+        } else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
                 vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
-                                  dev->dev_addr, dev->addr_len);
+                                  addr->sa_data, dev->addr_len);
+        }
+
+        eth_commit_mac_addr_change(dev, p);
 
         return 0;
 }
@@ -1627,6 +1641,7 @@ static unsigned int features[] = {
         VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
         VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
         VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
+        VIRTIO_NET_F_CTRL_MAC_ADDR,
 };
 
 static struct virtio_driver virtio_net_driver = {