power9 powervm qemu test - help needed!

hi!

I'm starting to document the QEMU setups i've figured out for booting
various powerpc/risc-v platforms and since power9 (and yes power8,
heh) is on my mind, I'd like to at least get those shook out so others
can jump in and tinker.

Specifically, I've figured out enough to get a working QEMU powervm 9
setup. Well, mostly working:

https://wiki.freebsd.org/powerpc/QEMU/POWERVM9

It works enough to boot to the installer in both power8 and power9,
but both seem unable to successfully complete the mfi (megaraid SAS)
driver initialisation. It's hung during attach/initialise waiting for
some firmware command(s) to finish. It could be as simple as interrupt
routing not setup right, I don't know.

I'm currently neck deep in testing, filing bugs and figuring out other
sharp corners. I'd super appreciate it if someone would dig into
what's broken in either our driver or QEMU support for that so we can
fix it in -16 and -15 and then use these to stand up some automated
testing.

(And you don't need hardware. and you have gdb/kgdb into the QEMU VM
itself to figure out what's going on. And you can inspect the CPU
state! It's fun.)

Thanks,



-adrian