Being that there is many different types of virtualization, some running in parallel to the guest o/s wouldn't it be possible to set it up so that a section of resources are blocked off and run at a lower point so that the guest o/s isn't touched what so ever, short of resource sharing?
None of the virtualization methods that I have researched do this. Think about it
if that were true then there would not be a need for a "HostOS". As well as having
full 3D performance (QEMU has some of that code written as well as VMware). That
you could also total take down the NIC and everything else would work at the VM.
The mention that the HostOS is not touched is not really correct, the
method is using a loop back device. Then that is used to then loop
into the real NIC. As I hope you can see the device is being used by the
HostOS in both directions.
Second since there is a HostOS then you have the inherent security problems
with also the security problems with virtualization.