Though I don't have deep understanding in in Virtualization but learned few basic terms of virtualization. As per understanding if a hyper visor run directly on hardware is considered as type 1 hyper visor while few other hyper-visors are available which run on top of host operating system. I am not 100% sure but I think QEMU lies under the hyper-visor type 1 category and Oracle Virtual Box comes under the type-2. Please correct me if I am wrong.