Test environment for non-native archs

[Rich Felker <dalias@aerifal.cx>]

Hi,

I've been thinking a bit about further testing of ARM (for which I
don't have a native environment) and ports to other systems, and
realized that to be able to efficiently mix working on the native host
and virtual target system (e.g. doing most of the compiling on the
host), it's going to be desirable to have the Linux running under qemu
using part of the host's filesystem as its root fs, instead of having
a filesystem image.

This seems to be possible with qemu's support for exporting a virtual
9p share to the guest OS, but I haven't yet determined if it's
possible to boot directly with the 9p share as the root fs, or whether
it's going to require a separate initial fs image and switch/pivot
root afterwards (as you can tell, I'm not very familiar with this sort
of setup).

Anyone know the answer, or have some recipes I could use?

Rich