Fiasco.OC-UX on MIPS?

[Paul Boddie]

On Monday 19. August 2019 00.31.16 Adam Lackorzynski wrote:
> Hi Paul,
> 
> UX is an interesting way of virtualizing a kernel and gives interesting
> insights into both Fiasco and Linux. I guess with some work it would be
> well possible to make this work on MIPS.

After writing my message, I did think of pursuing a simpler, iterative 
approach to making the kernel run as a Linux process, ultimately employing 
most of the same techniques but without trying to adapt the existing UX code.

> But, before going on this endeavor what about QEMU? It should be much
> quicker and simpler to run it through QEMU,

This did occur to me: after all, what is mostly needed is a way of emulating 
the privileged instructions, and QEMU is a general framework for achieving 
this. (The documentation isn't completely clear about whether I would end up 
emulating everything even on the same architecture.)

So, I have built Fiasco and L4Re for the MIPS Malta platform, and it seems to 
be possible to launch a system using the Makefile. For instance:

make O=mybuild qemu E=hello

However, I imagine that either a graphical example is needed where the SDL 
interface for QEMU is being used, or that some options are required to get 
QEMU to use a simple serial console. There appear to be some options and the 
possibility to do something like this:

make O=mybuild qemu E=hello QEMU_OPTIONS='-nographic'

Maybe even the machine type is necessary amongst the options as well. This 
doesn't seem to produce output, though.

I have to ask: what do people actually use when developing L4Re and Fiasco?

Paul