[Qemu-devel] Binary Translation hooking - reading registers

["felix.matenaar@rwth-aachen" <felix.matenaar@rwth-aachen.de>]

Hello everyone,

i am working on a project adding instrumentation into qemu. My approach
is to use gen_helper stuff do hook specific opcodes like call or ret to
gain information about running processes in the virtual machine.

Today I noticed that the CPUState* env is not in all cases up-to-date
when my hooks are called on block execution. That makes totally sense
since blocks are natively executed in one step as far as I understood so
there is no code which would keep the cpu environment up-to-date.

To achieve my goal, it is necessary being able reading actual register
configuration like eax when a ret hook is called to get a function
return value. So my question is how I can do this. Are there already
some functions which generate code to update the cpu environment? If
not, is there anything you can point me towards for adding support?

Target is windows XP on i386.

Regards,
    Felix