New configure option RTEMS_VIRTUAL

[Philipp Eppelt]

Hi,

in my GSOC project I aim for a virtualized version of RTEMS. I develop
it for the i386 target and moved the interrupt.h code to libcpu to be
included dependent on the CPU target. So a native cpu still gets the
normal code, but the virtual one will call the virtualization layer.

This leads to an #include<libcpu/interrupt.h> in
cpukit/score/cpu/i386/rtems/score/cpu.h. I was told it is not allowed to
include files in cpukit from outside cpukit.
As this is performance critical code the interrupt macros can't be
replaced with function, which would enable me to declare the functions
in cpukit and implement them in libcpu.

The only satisfying way to compile the interrupt code dependent on
native or virtual environment is to introduce a configuration option
similar to RTEMS_SMP and RTEMS_MULTIPROCESSING:

RTEMS_HYPERVISOR or RTEMS_VIRTUAL


Other options:
:Introduce a new CPU target:
Besides i386 a new CPU i386-virtual could be introduced. This adds a lot
of duplicated code. The only difference would be 160 lines of code.


In the future this option can be used for other projects virtualizing
RTEMS on top of some hypervisor with any target CPU.


Do you have other ideas?
What do you think about this?


Cheers,
Philipp