> * You have only one kernel, so you're not duplicating the work and memory usage of the kernel.
One other point is that a single kernel can make much better scheduling decisions for processes across multiple CPU cores than for virtualized SMP blobs. To run a vSMP blob you have to clear the decks on the assigned CPU cores, reset them to an expected state and then give exclusive access to the VM for its time slice, without really knowing what its doing.