vdpa: support set mac address from vdpa tool

Add new UAPI to support the mac address from vdpa tool
Function vdpa_nl_cmd_dev_attr_set_doit() will get the
new MAC address from the vdpa tool and then set it to the device.

The usage is: vdpa dev set name vdpa_name mac **:**:**:**:**:**

Here is example:
root@L1# vdpa -jp dev config show vdpa0
{
"config": {
"vdpa0": {
"mac": "82:4d:e9:5d:d7:e6",
"link ": "up",
"link_announce ": false,
"mtu": 1500
}
}
}

root@L1# vdpa dev set name vdpa0 mac 00:11:22:33:44:55

root@L1# vdpa -jp dev config show vdpa0
{
"config": {
"vdpa0": {
"mac": "00:11:22:33:44:55",
"link ": "up",
"link_announce ": false,
"mtu": 1500
}
}
}

Signed-off-by: Cindy Lu <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>
Acked-by: Jason Wang <[e-mail]>

drivers/vdpa/vdpa.c

···
 	return err;
 }
 
+static int vdpa_dev_net_device_attr_set(struct vdpa_device *vdev,
+					struct genl_info *info)
+{
+	struct vdpa_dev_set_config set_config = {};
+	struct vdpa_mgmt_dev *mdev = vdev->mdev;
+	struct nlattr **nl_attrs = info->attrs;
+	const u8 *macaddr;
+	int err = -EOPNOTSUPP;
+
+	down_write(&vdev->cf_lock);
+	if (nl_attrs[VDPA_ATTR_DEV_NET_CFG_MACADDR]) {
+		set_config.mask |= BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MACADDR);
+		macaddr = nla_data(nl_attrs[VDPA_ATTR_DEV_NET_CFG_MACADDR]);
+
+		if (is_valid_ether_addr(macaddr)) {
+			ether_addr_copy(set_config.net.mac, macaddr);
+			if (mdev->ops->dev_set_attr) {
+				err = mdev->ops->dev_set_attr(mdev, vdev,
+							      &set_config);
+			} else {
+				NL_SET_ERR_MSG_FMT_MOD(info->extack,
+						       "Operation not supported by the device.");
+			}
+		} else {
+			NL_SET_ERR_MSG_FMT_MOD(info->extack,
+					       "Invalid MAC address");
+		}
+	}
+	up_write(&vdev->cf_lock);
+	return err;
+}
+
+static int vdpa_nl_cmd_dev_attr_set_doit(struct sk_buff *skb,
+					 struct genl_info *info)
+{
+	struct vdpa_device *vdev;
+	struct device *dev;
+	const char *name;
+	u64 classes;
+	int err = 0;
+
+	if (!info->attrs[VDPA_ATTR_DEV_NAME])
+		return -EINVAL;
+
+	name = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);
+
+	down_write(&vdpa_dev_lock);
+	dev = bus_find_device(&vdpa_bus, NULL, name, vdpa_name_match);
+	if (!dev) {
+		NL_SET_ERR_MSG_MOD(info->extack, "device not found");
+		err = -ENODEV;
+		goto dev_err;
+	}
+	vdev = container_of(dev, struct vdpa_device, dev);
+	if (!vdev->mdev) {
+		NL_SET_ERR_MSG_MOD(info->extack, "unmanaged vdpa device");
+		err = -EINVAL;
+		goto mdev_err;
+	}
+	classes = vdpa_mgmtdev_get_classes(vdev->mdev, NULL);
+	if (classes & BIT_ULL(VIRTIO_ID_NET)) {
+		err = vdpa_dev_net_device_attr_set(vdev, info);
+	} else {
+		NL_SET_ERR_MSG_FMT_MOD(info->extack, "%s device not supported",
+				       name);
+	}
+
+mdev_err:
+	put_device(dev);
+dev_err:
+	up_write(&vdpa_dev_lock);
+	return err;
+}
+
 static int vdpa_dev_config_dump(struct device *dev, void *data)
 {
 	struct vdpa_device *vdev = container_of(dev, struct vdpa_device, dev);
···
 	{
 		.cmd = VDPA_CMD_DEV_VSTATS_GET,
 		.doit = vdpa_nl_cmd_dev_stats_get_doit,
+		.flags = GENL_ADMIN_PERM,
+	},
+	{
+		.cmd = VDPA_CMD_DEV_ATTR_SET,
+		.doit = vdpa_nl_cmd_dev_attr_set_doit,
 		.flags = GENL_ADMIN_PERM,
 	},
 };

include/linux/vdpa.h

···
  *	     @dev: vdpa device to remove
  *	     Driver need to remove the specified device by calling
  *	     _vdpa_unregister_device().
+ * @dev_set_attr: change a vdpa device's attr after it was create
+ *	     @mdev: parent device to use for device
+ *	     @dev: vdpa device structure
+ *	     @config:Attributes to be set for the device.
+ *	     The driver needs to check the mask of the structure and then set
+ *	     the related information to the vdpa device. The driver must return 0
+ *	     if set successfully.
  */
 struct vdpa_mgmtdev_ops {
 	int (*dev_add)(struct vdpa_mgmt_dev *mdev, const char *name,
 		       const struct vdpa_dev_set_config *config);
 	void (*dev_del)(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev);
+	int (*dev_set_attr)(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev,
+			    const struct vdpa_dev_set_config *config);
 };
 
 /**

include/uapi/linux/vdpa.h

···
 	VDPA_CMD_DEV_GET,		/* can dump */
 	VDPA_CMD_DEV_CONFIG_GET,	/* can dump */
 	VDPA_CMD_DEV_VSTATS_GET,
+	VDPA_CMD_DEV_ATTR_SET,
 };
 
 enum vdpa_attr {