I was just reviewing this stuff this morning on the laptop while on the train. I checked my RSS feeds and I saw that Kurt Roggen was doing some blogging recently (and doing a nice job too).
Understanding things like VMBus, VSC’s and VSP’s is recommended when working with Hyper-V. This post will teach you some of this.
What I’ll add to this is that your VM’s (child partitions) have a 1-1 connection to the parent partition. This secure channel, the VMBus, is at Ring 0 and is protected by Data Execution Protection (DEP). This is why turning this on in the BIOS is a requirement for installing Hyper-V.
Credit: Kurt Roggen.