Let’s continue with our virtualization school for beginners. In my previous post, I have explained Type 2 virtualization. In this post, I’ll give you simple schema and description of Hybrid virtualization. In this virtualizaton type, both host OS and Virtual Machine Manager (VMM) run directly on the hardware, but with different levels of access to hardware components.
But, in real life, VMM still must go through host OS to access hardware. The host OS and VMM are both running in kernel mode and so they are essentially playing tug o’war with the CPU. The host gets CPU cycles when it need them in the host context and then passes cycles back to the VMM and the VMM services then provide cycles to the guest OSs. The reason why the Hybrid model is faster is that VMM is running in kernel mode as opposed to the Type2 model where the VMM generally runs in User mode.
I’m sure that you have already seen (and perhaps used) this type of virtualization. Have you ever tried Microsoft Virtual PC 2007 or Microsoft Virtual Server 2005 R2, or maybe WMWare Player? If yes, that means that you have user hybrid virtualization to virtualize some of your operating systems.
It’s is used widely because it’s performance is very good, but not as good as having separate physical machines.