---
changelog:
v3->v4:
 - removed config space fields reporting which are not used by mlx5
   and sim drivers
---
 drivers/vdpa/vdpa.c       | 176 ++++++++++++++++++++++++++++++++++++++
 include/linux/vdpa.h      |   2 +
 include/uapi/linux/vdpa.h |   6 ++
 3 files changed, 184 insertions(+)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index d42697699366..973c56fb60b9 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. */

@@ -66,6 +68,7 @@ static void vdpa_release_dev(struct device *d)
                ops->free(vdev);

        ida_simple_remove(&vdpa_index_ida, vdev->index);
+       mutex_destroy(&vdev->cf_mutex);
        kfree(vdev);
 }

@@ -127,6 +130,7 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
        if (err)
                goto err_name;

+       mutex_init(&vdev->cf_mutex);
        device_initialize(&vdev->dev);

        return vdev;

@@ -309,6 +313,7 @@ void vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
 {
        const struct vdpa_config_ops *ops = vdev->config;

+       mutex_lock(&vdev->cf_mutex);
        /*
         * Config accesses aren't supposed to trigger before features are set.
         * If it does happen we assume a legacy guest.

@@ -316,6 +321,7 @@ void vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
        if (!vdev->features_valid)
                vdpa_set_features(vdev, 0);
        ops->get_config(vdev, offset, buf, len);
+       mutex_unlock(&vdev->cf_mutex);
 }
 EXPORT_SYMBOL_GPL(vdpa_get_config);

@@ -329,7 +335,9 @@ EXPORT_SYMBOL_GPL(vdpa_get_config);
 void vdpa_set_config(struct vdpa_device *vdev, unsigned int offset,
                     const void *buf, unsigned int length)
 {
+       mutex_lock(&vdev->cf_mutex);
        vdev->config->set_config(vdev, offset, buf, length);
+       mutex_unlock(&vdev->cf_mutex);
 }
 EXPORT_SYMBOL_GPL(vdpa_set_config);

@@ -661,6 +669,168 @@ 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, u64 features,
+                                      const struct virtio_net_config *config)
+{
+       u16 val_u16;
+
+       if ((features & (1ULL << VIRTIO_NET_F_MQ)) == 0)
+               return 0;
+
+       val_u16 = le16_to_cpu(config->max_virtqueue_pairs);
+       return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, val_u16);
+}
+
+static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
+{
+       struct virtio_net_config config = {};
+       u64 features;
+       u16 val_u16;
+
+       vdpa_get_config(vdev, 0, &config, sizeof(config));
+
+       if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac),
+                   config.mac))
+               return -EMSGSIZE;
+
+       val_u16 = le16_to_cpu(config.status);
+       if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16))
+               return -EMSGSIZE;
+
+       val_u16 = le16_to_cpu(config.mtu);
+       if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
+               return -EMSGSIZE;
+
+       features = vdev->config->get_features(vdev);
+
+       return vdpa_dev_net_mq_config_fill(vdev, msg, features, &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 },

@@ -692,6 +862,12 @@ 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/linux/vdpa.h b/include/linux/vdpa.h
index 267236aab34c..5cc5e501397f 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h

@@ -63,6 +63,7 @@ struct vdpa_mgmt_dev;
  * @dev: underlying device
  * @dma_dev: the actual device that is performing DMA
  * @config: the configuration ops for this device.
+ * @cf_mutex: Protects get and set access to configuration layout.
  * @index: device index
  * @features_valid: were features initialized? for legacy guests
  * @use_va: indicate whether virtual address must be used by this device

@@ -74,6 +75,7 @@ struct vdpa_device {
        struct device dev;
        struct device *dma_dev;
        const struct vdpa_config_ops *config;
+       struct mutex cf_mutex; /* Protects get/set config */
        unsigned int index;
        bool features_valid;
        bool use_va;

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index e3b87879514c..a252f06f9dfd 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 {

@@ -34,6 +35,11 @@ enum vdpa_attr {
        VDPA_ATTR_DEV_MAX_VQ_SIZE,              /* u16 */
        VDPA_ATTR_DEV_MIN_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 */
+
        /* new attributes must be added above here */
        VDPA_ATTR_MAX,
 };
--

2.25.4