Subject: Re: [PATCH 1/2] vdpa: support set mac address from vdpa tool

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 12 Jun 2024 03:12:47 -0400

On Tue, Jun 11, 2024 at 01:32:32PM +0800, Cindy Lu wrote:
> Add new UAPI to support the mac address from vdpa tool

The patch does not do what commit log says.
Instead there's an internal API to set mac and
a UAPI to write into config space.

> Function vdpa_nl_cmd_dev_config_set_doit() will get the
> 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 sample:
> 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 <[email-masked]>
> ---
>  drivers/vdpa/vdpa.c       | 71 +++++++++++++++++++++++++++++++++++++++
>  include/linux/vdpa.h      |  2 ++
>  include/uapi/linux/vdpa.h |  1 +
>  3 files changed, 74 insertions(+)
> 
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index a7612e0783b3..347ae6e7749d 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -1149,6 +1149,72 @@ static int vdpa_nl_cmd_dev_config_get_doit(struct sk_buff *skb, struct genl_info
>  	return err;
>  }
>  
> +static int vdpa_nl_cmd_dev_config_set_doit(struct sk_buff *skb,
> +					   struct genl_info *info)
> +{
> +	struct vdpa_dev_set_config set_config = {};
> +	struct nlattr **nl_attrs = info->attrs;
> +	struct vdpa_mgmt_dev *mdev;
> +	const u8 *macaddr;
> +	const char *name;
> +	int err = 0;
> +	struct device *dev;
> +	struct vdpa_device *vdev;
> +
> +	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,
> +			"Fail to find the specified management device");
> +		err = -EINVAL;
> +		goto mdev_err;
> +	}
> +	mdev = vdev->mdev;
> +	if (nl_attrs[VDPA_ATTR_DEV_NET_CFG_MACADDR]) {
> +		if (!(mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MAC))) {

Seems to poke at a device without even making sure it's a network
device.

> +			NL_SET_ERR_MSG_FMT_MOD(
> +				info->extack,
> +				"Missing features 0x%llx for provided attributes",
> +				BIT_ULL(VIRTIO_NET_F_MAC));
> +			err = -EINVAL;
> +			goto mdev_err;
> +		}
> +		macaddr = nla_data(nl_attrs[VDPA_ATTR_DEV_NET_CFG_MACADDR]);
> +		memcpy(set_config.net.mac, macaddr, ETH_ALEN);
> +		set_config.mask |= BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MACADDR);
> +		if (mdev->ops->set_mac) {
> +			err = mdev->ops->set_mac(mdev, vdev, &set_config);
> +		} else {
> +			NL_SET_ERR_MSG_FMT_MOD(
> +				info->extack,
> +				"%s device not support set mac address ", name);
> +		}
> +
> +	} else {
> +		NL_SET_ERR_MSG_FMT_MOD(info->extack,
> +				       "%s device not support this config ",
> +				       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);
> @@ -1285,6 +1351,11 @@ static const struct genl_ops vdpa_nl_ops[] = {
>  		.doit = vdpa_nl_cmd_dev_stats_get_doit,
>  		.flags = GENL_ADMIN_PERM,
>  	},
> +	{
> +		.cmd = VDPA_CMD_DEV_CONFIG_SET,
> +		.doit = vdpa_nl_cmd_dev_config_set_doit,
> +		.flags = GENL_ADMIN_PERM,
> +	},
>  };
>  
>  static struct genl_family vdpa_nl_family __ro_after_init = {
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index db15ac07f8a6..c97f4f1da753 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -581,6 +581,8 @@ 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 (*set_mac)(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev,
> +		       const struct vdpa_dev_set_config *config);

Well, now vdpa_mgmtdev_ops which was completely generic is growing
a net specific interface. Which begs a question - how is this
going to work with other device types?

>  };
>  
>  /**
> diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
> index 54b649ab0f22..53f249fb26bc 100644
> --- a/include/uapi/linux/vdpa.h
> +++ b/include/uapi/linux/vdpa.h
> @@ -19,6 +19,7 @@ enum vdpa_command {
>  	VDPA_CMD_DEV_GET,		/* can dump */
>  	VDPA_CMD_DEV_CONFIG_GET,	/* can dump */
>  	VDPA_CMD_DEV_VSTATS_GET,
> +	VDPA_CMD_DEV_CONFIG_SET,
>  };
>  
>  enum vdpa_attr {
> -- 
> 2.45.0