Paravirtualization project - GSOC 2013

[Philipp Eppelt]

Hi,

I was thinking about the CPU issue mentioned in the last years ARINC 653 
project.

How can a BSP be written, that has no corresponding CPU?
To be precise:
	c/src/lib/libbsp/paraVirt/
	without cpukit/score/cpu/paraVirt/

This should ease the usage across different CPUs. So the amount of 
platform dependent code is reduced.

But another idea crossed my mind. Why not use a approach similar to the 
no_cpu?
This would mean to provide a virtual CPU model with a manual describing 
how to fill in the CPU dependent code.
Also, introduce a x86_virt (sparc_virt, sparc64_virt and so on) CPU model.
To prevent clobbering the cpukit/score/cpu/ directory they all go into 
cpukit/score/cpu/virtCPU/ and an additional configuration parameter 
should specify the cpu used.
So instead of --target=i386-rtems4.11 we use --target=virt-rtems4.11 
--enableVirtualCPU=i386. (like --enableBSP=)
And the platform independent stuff goes into cpukit/score/cpu/virtCPU/shared


What do you think? Is this feasible?

Regards,
Philipp