vdpa/mlx5: Enable user to add/delete vdpa device

Allow to control vdpa device creation and destruction using the vdpa
management tool.

Examples:
1. List the management devices
$ vdpa mgmtdev show
pci/0000:3b:00.1:
  supported_classes net

2. Create vdpa instance
$ vdpa dev add mgmtdev pci/0000:3b:00.1 name vdpa0

3. Show vdpa devices
$ vdpa dev show
vdpa0: type network mgmtdev pci/0000:3b:00.1 vendor_id 5555 max_vqs 16 \
max_vq_size 256

Signed-off-by: Eli Cohen <elic@nvidia.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210408091320.4600-1-elic@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1974,23 +1974,32 @@ static void init_mvqs(struct mlx5_vdpa_net *ndev)
 	}
 }
 
-static int mlx5v_probe(struct auxiliary_device *adev,
+struct mlx5_vdpa_mgmtdev {
-		       const struct auxiliary_device_id *id)
+	struct vdpa_mgmt_dev mgtdev;
+	struct mlx5_adev *madev;
+	struct mlx5_vdpa_net *ndev;
+};
+
+static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name)
 {
-	struct mlx5_adev *madev = container_of(adev, struct mlx5_adev, adev);
+	struct mlx5_vdpa_mgmtdev *mgtdev = container_of(v_mdev, struct mlx5_vdpa_mgmtdev, mgtdev);
-	struct mlx5_core_dev *mdev = madev->mdev;
 	struct virtio_net_config *config;
 	struct mlx5_vdpa_dev *mvdev;
 	struct mlx5_vdpa_net *ndev;
+	struct mlx5_core_dev *mdev;
 	u32 max_vqs;
 	int err;
 
+	if (mgtdev->ndev)
+		return -ENOSPC;
+
+	mdev = mgtdev->madev->mdev;
 	/* we save one virtqueue for control virtqueue should we require it */
 	max_vqs = MLX5_CAP_DEV_VDPA_EMULATION(mdev, max_num_virtio_queues);
 	max_vqs = min_t(u32, max_vqs, MLX5_MAX_SUPPORTED_VQS);
 
 	ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mlx5_vdpa_ops,
-				 NULL);
+				 name);
 	if (IS_ERR(ndev))
 		return PTR_ERR(ndev);
 
@@ -2017,11 +2026,12 @@ static int mlx5v_probe(struct auxiliary_device *adev,
 	if (err)
 		goto err_res;
 
-	err = vdpa_register_device(&mvdev->vdev, 2 * mlx5_vdpa_max_qps(max_vqs));
+	mvdev->vdev.mdev = &mgtdev->mgtdev;
+	err = _vdpa_register_device(&mvdev->vdev, 2 * mlx5_vdpa_max_qps(max_vqs));
 	if (err)
 		goto err_reg;
 
-	dev_set_drvdata(&adev->dev, ndev);
+	mgtdev->ndev = ndev;
 	return 0;
 
 err_reg:
@@ -2034,11 +2044,62 @@ static int mlx5v_probe(struct auxiliary_device *adev,
 	return err;
 }
 
+static void mlx5_vdpa_dev_del(struct vdpa_mgmt_dev *v_mdev, struct vdpa_device *dev)
+{
+	struct mlx5_vdpa_mgmtdev *mgtdev = container_of(v_mdev, struct mlx5_vdpa_mgmtdev, mgtdev);
+
+	_vdpa_unregister_device(dev);
+	mgtdev->ndev = NULL;
+}
+
+static const struct vdpa_mgmtdev_ops mdev_ops = {
+	.dev_add = mlx5_vdpa_dev_add,
+	.dev_del = mlx5_vdpa_dev_del,
+};
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static int mlx5v_probe(struct auxiliary_device *adev,
+		       const struct auxiliary_device_id *id)
+
+{
+	struct mlx5_adev *madev = container_of(adev, struct mlx5_adev, adev);
+	struct mlx5_core_dev *mdev = madev->mdev;
+	struct mlx5_vdpa_mgmtdev *mgtdev;
+	int err;
+
+	mgtdev = kzalloc(sizeof(*mgtdev), GFP_KERNEL);
+	if (!mgtdev)
+		return -ENOMEM;
+
+	mgtdev->mgtdev.ops = &mdev_ops;
+	mgtdev->mgtdev.device = mdev->device;
+	mgtdev->mgtdev.id_table = id_table;
+	mgtdev->madev = madev;
+
+	err = vdpa_mgmtdev_register(&mgtdev->mgtdev);
+	if (err)
+		goto reg_err;
+
+	dev_set_drvdata(&adev->dev, mgtdev);
+
+	return 0;
+
+reg_err:
+	kfree(mgtdev);
+	return err;
+}
+
 static void mlx5v_remove(struct auxiliary_device *adev)
 {
-	struct mlx5_vdpa_dev *mvdev = dev_get_drvdata(&adev->dev);
+	struct mlx5_vdpa_mgmtdev *mgtdev;
 
-	vdpa_unregister_device(&mvdev->vdev);
+	mgtdev = dev_get_drvdata(&adev->dev);
+	vdpa_mgmtdev_unregister(&mgtdev->mgtdev);
+	kfree(mgtdev);
 }
 
 static const struct auxiliary_device_id mlx5v_id_table[] = {