Re: [Qemu-devel] [PATCH v2] target-arm: Extract some external ARM CPU API

[Pavel Fedin]

 Hello!

> But Peter C has a better grasp of the current status of
> multiarch than I do, so if he prefers using obj-y then
> I'm happy to take his recommendation.

 I am neutral, and i will accept any solution. OTOH, he agreed with my proposal 
too, and even promised to pick it up into his patchsets, but suggested to 
change include pathname to include/hw/arm/cpu.h. And i have the last concern 
about it because hw/arm/ is a place where board-specific includes are placed.
 Additionally, we already have three more specific ARM CPU files in 
include/hw/cpu/, so they just look nice together.

 And you know... Theoretically... As far as i can understand, multi-arch is a 
way to enable emulation of heterogeneous systems, which combine different CPUs. 
Am i right about it? In this case, what if in future we have some heterogeneous 
HW, where e.g. ARM and x86 are interoperating using system registers? In this 
case, x86-targeted qemu code would probably have to talk to ARM-targeted one. 
And having this API separated from the inner CPU guts would only help.
 Compared to this architectural improvement, obj-y looks like very simple way 
to ignore, but not to solve the problem. :)

 So, Peter C, what is your final decision?

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia