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>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 395ab4ff3e64f1721fa335ff7649f01c2a4f67b5..701408a1ded6b50aae333b1cd709d9da7bfc35f8 100644 (file)
--- 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 = {

diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 848e3584d7c8063759548eb4f440e7b2bf262126..a5a8c88753b9579e8bcc9caed170a6f859a163b1 100644 (file)
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -53,6 +53,7 @@
                                         * network */
 #define VIRTIO_NET_F_MQ        22      /* Device supports Receive Flow
                                         * Steering */
+#define VIRTIO_NET_F_CTRL_MAC_ADDR 23  /* Set MAC address */
 
 #define VIRTIO_NET_S_LINK_UP   1       /* Link is up */
 #define VIRTIO_NET_S_ANNOUNCE  2       /* Announcement is needed */
@@ -127,7 +128,7 @@ typedef __u8 virtio_net_ctrl_ack;
  #define VIRTIO_NET_CTRL_RX_NOBCAST      5
 
 /*
- * Control the MAC filter table.
+ * Control the MAC
  *
  * The MAC filter table is managed by the hypervisor, the guest should
  * assume the size is infinite.  Filtering should be considered
@@ -140,6 +141,10 @@ typedef __u8 virtio_net_ctrl_ack;
  * first sg list contains unicast addresses, the second is for multicast.
  * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
  * is available.
+ *
+ * The ADDR_SET command requests one out scatterlist, it contains a
+ * 6 bytes MAC address. This functionality is present if the
+ * VIRTIO_NET_F_CTRL_MAC_ADDR feature is available.
  */
 struct virtio_net_ctrl_mac {
        __u32 entries;
@@ -148,6 +153,7 @@ struct virtio_net_ctrl_mac {
 
 #define VIRTIO_NET_CTRL_MAC    1
  #define VIRTIO_NET_CTRL_MAC_TABLE_SET        0
+ #define VIRTIO_NET_CTRL_MAC_ADDR_SET         1
 
 /*
  * Control VLAN filtering