Spdk/test/external_code/hello_world/bdev.conf

{
  "subsystems": [
    {
      "subsystem": "bdev",
      "config": [
        {
          "params": {
            "name": "Malloc0",
            "block_size": 4096,
            "num_blocks": 32
          },
          "method": "construct_malloc_bdev"
        }
      ]
    }
  ]
}