[Lguest] Passing information from launcher to guest

[Eviatar Khen]

Hi all,

I could use some ideas for the following problem. I need that running
guests would have the ability to answer the question: am I guest of type
X or not?
The launcher needs to decide whether the guest is X or not, and the
guest should conclude this while running.
Using a hypercall would not work because that current hypercall
mechanism does not return a value (actually it returns that hypercall
number).
The only idea that I have is put an indication ,if the guest is X or
not, somewhere in a physical address that would be foreknown to both the
launcher and the guest. I think that this requires writing some assembly
code which I prefer to avoid.
Does anyone have some other ideas?

Thank you and best regards,

Eviatar