[PATCH linux-next 2/9] vdpa: Introduce query of device config layout

[Parav Pandit <parav@nvidia.com>]

Introduce a command to query a device config layout.

An example query of network vdpa device:

$ vdpa dev add name bar mgmtdev vdpasim_net

$ vdpa dev config show
bar: mac 00:35:09:19:48:05 link up link_announce false mtu 1500 speed 0 duplex 0

$ vdpa dev config show -jp
{
    "config": {
        "bar": {
            "mac": "00:35:09:19:48:05",
            "link ": "up",
            "link_announce ": false,
            "mtu": 1500,
            "speed": 0,
            "duplex": 0
        }
    }
}

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
---
changelog:
v1->v2:
 - read whole net config layout instead of individual fields
 - added error extack for unmanaged vdpa device
---
 drivers/vdpa/vdpa.c       | 181 ++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/vdpa.h |  11 +++
 2 files changed, 192 insertions(+)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 3d997b389345..cebbba500638 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -14,6 +14,8 @@
 #include <uapi/linux/vdpa.h>
 #include <net/genetlink.h>
 #include <linux/mod_devicetable.h>
+#include <linux/virtio_net.h>
+#include <linux/virtio_ids.h>
 
 static LIST_HEAD(mdev_head);
 /* A global mutex that protects vdpa management device and device level operations. */
@@ -603,6 +605,179 @@ static int vdpa_nl_cmd_dev_get_dumpit(struct sk_buff *msg, struct netlink_callba
 	return msg->len;
 }
 
+static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev,
+				       struct sk_buff *msg,
+				       const struct virtio_net_config *config)
+{
+	u32 hash_types;
+	u16 rss_field;
+	u64 features;
+
+	features = vdev->config->get_features(vdev);
+	if ((features & (1ULL << VIRTIO_NET_F_MQ)) == 0)
+		return 0;
+
+	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP,
+			config->max_virtqueue_pairs))
+		return -EMSGSIZE;
+	if (nla_put_u8(msg, VDPA_ATTR_DEV_NET_CFG_RSS_MAX_KEY_LEN,
+		       config->rss_max_key_size))
+		return -EMSGSIZE;
+
+	rss_field = le16_to_cpu(config->rss_max_key_size);
+	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_RSS_MAX_IT_LEN, rss_field))
+		return -EMSGSIZE;
+
+	hash_types = le32_to_cpu(config->supported_hash_types);
+	if (nla_put_u32(msg, VDPA_ATTR_DEV_NET_CFG_RSS_HASH_TYPES,
+			config->supported_hash_types))
+		return -EMSGSIZE;
+	return 0;
+}
+
+static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
+{
+	struct virtio_net_config config = {};
+
+	vdev->config->get_config(vdev, 0, &config, sizeof(config));
+	if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac), config.mac))
+		return -EMSGSIZE;
+	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, config.status))
+		return -EMSGSIZE;
+	if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, config.mtu))
+		return -EMSGSIZE;
+	if (nla_put_u32(msg, VDPA_ATTR_DEV_NET_CFG_SPEED, config.speed))
+		return -EMSGSIZE;
+	if (nla_put_u8(msg, VDPA_ATTR_DEV_NET_CFG_DUPLEX, config.duplex))
+		return -EMSGSIZE;
+
+	return vdpa_dev_net_mq_config_fill(vdev, msg, &config);
+}
+
+static int
+vdpa_dev_config_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq,
+		     int flags, struct netlink_ext_ack *extack)
+{
+	u32 device_id;
+	void *hdr;
+	int err;
+
+	hdr = genlmsg_put(msg, portid, seq, &vdpa_nl_family, flags,
+			  VDPA_CMD_DEV_CONFIG_GET);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (nla_put_string(msg, VDPA_ATTR_DEV_NAME, dev_name(&vdev->dev))) {
+		err = -EMSGSIZE;
+		goto msg_err;
+	}
+
+	device_id = vdev->config->get_device_id(vdev);
+	if (nla_put_u32(msg, VDPA_ATTR_DEV_ID, device_id)) {
+		err = -EMSGSIZE;
+		goto msg_err;
+	}
+
+	switch (device_id) {
+	case VIRTIO_ID_NET:
+		err = vdpa_dev_net_config_fill(vdev, msg);
+		break;
+	default:
+		err = -EOPNOTSUPP;
+		break;
+	}
+	if (err)
+		goto msg_err;
+
+	genlmsg_end(msg, hdr);
+	return 0;
+
+msg_err:
+	genlmsg_cancel(msg, hdr);
+	return err;
+}
+
+static int vdpa_nl_cmd_dev_config_get_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct vdpa_device *vdev;
+	struct sk_buff *msg;
+	const char *devname;
+	struct device *dev;
+	int err;
+
+	if (!info->attrs[VDPA_ATTR_DEV_NAME])
+		return -EINVAL;
+	devname = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	mutex_lock(&vdpa_dev_mutex);
+	dev = bus_find_device(&vdpa_bus, NULL, devname, 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;
+	}
+	err = vdpa_dev_config_fill(vdev, msg, info->snd_portid, info->snd_seq,
+				   0, info->extack);
+	if (!err)
+		err = genlmsg_reply(msg, info);
+
+mdev_err:
+	put_device(dev);
+dev_err:
+	mutex_unlock(&vdpa_dev_mutex);
+	if (err)
+		nlmsg_free(msg);
+	return err;
+}
+
+static int vdpa_dev_config_dump(struct device *dev, void *data)
+{
+	struct vdpa_device *vdev = container_of(dev, struct vdpa_device, dev);
+	struct vdpa_dev_dump_info *info = data;
+	int err;
+
+	if (!vdev->mdev)
+		return 0;
+	if (info->idx < info->start_idx) {
+		info->idx++;
+		return 0;
+	}
+	err = vdpa_dev_config_fill(vdev, info->msg, NETLINK_CB(info->cb->skb).portid,
+				   info->cb->nlh->nlmsg_seq, NLM_F_MULTI,
+				   info->cb->extack);
+	if (err)
+		return err;
+
+	info->idx++;
+	return 0;
+}
+
+static int
+vdpa_nl_cmd_dev_config_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
+{
+	struct vdpa_dev_dump_info info;
+
+	info.msg = msg;
+	info.cb = cb;
+	info.start_idx = cb->args[0];
+	info.idx = 0;
+
+	mutex_lock(&vdpa_dev_mutex);
+	bus_for_each_dev(&vdpa_bus, NULL, &info, vdpa_dev_config_dump);
+	mutex_unlock(&vdpa_dev_mutex);
+	cb->args[0] = info.idx;
+	return msg->len;
+}
+
 static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
 	[VDPA_ATTR_MGMTDEV_BUS_NAME] = { .type = NLA_NUL_STRING },
 	[VDPA_ATTR_MGMTDEV_DEV_NAME] = { .type = NLA_STRING },
@@ -634,6 +809,12 @@ static const struct genl_ops vdpa_nl_ops[] = {
 		.doit = vdpa_nl_cmd_dev_get_doit,
 		.dumpit = vdpa_nl_cmd_dev_get_dumpit,
 	},
+	{
+		.cmd = VDPA_CMD_DEV_CONFIG_GET,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit = vdpa_nl_cmd_dev_config_get_doit,
+		.dumpit = vdpa_nl_cmd_dev_config_get_dumpit,
+	},
 };
 
 static struct genl_family vdpa_nl_family __ro_after_init = {
diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index 66a41e4ec163..5c31ecc3b956 100644
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h
@@ -17,6 +17,7 @@ enum vdpa_command {
 	VDPA_CMD_DEV_NEW,
 	VDPA_CMD_DEV_DEL,
 	VDPA_CMD_DEV_GET,		/* can dump */
+	VDPA_CMD_DEV_CONFIG_GET,	/* can dump */
 };
 
 enum vdpa_attr {
@@ -33,6 +34,16 @@ enum vdpa_attr {
 	VDPA_ATTR_DEV_MAX_VQS,			/* u32 */
 	VDPA_ATTR_DEV_MAX_VQ_SIZE,		/* u16 */
 
+	VDPA_ATTR_DEV_NET_CFG_MACADDR,		/* binary */
+	VDPA_ATTR_DEV_NET_STATUS,		/* u8 */
+	VDPA_ATTR_DEV_NET_CFG_MAX_VQP,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_MTU,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_SPEED,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_DUPLEX,		/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_RSS_MAX_KEY_LEN,	/* u8 */
+	VDPA_ATTR_DEV_NET_CFG_RSS_MAX_IT_LEN,	/* u16 */
+	VDPA_ATTR_DEV_NET_CFG_RSS_HASH_TYPES,	/* u32 */
+
 	/* new attributes must be added above here */
 	VDPA_ATTR_MAX,
 };
-- 
2.26.2

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