Re: [Qemu-discuss] No start with -cpu option

[Peter Maydell]

On Tue, 6 Aug 2019 at 17:32, Thomas <address@hidden> wrote:
> I try to start a 32bit PowerPC virtual machine to try Gentoo's ppc
> LiveCD.
> My host is an amd64 and I use QEMU emulator version 3.1.0.
>
> First I created a hd image:
> > qemu-img create -f qcow2 -o "preallocation=metadata" root.img 80G
>
> Then I tried to start qemu:
> > qemu-system-ppc -boot d -machine mac99,via=pmu -cpu '7447a_v1.2' -m 1G -hda 
> > root.img -cdrom install-powerpc-minimal-20190720T101002Z.iso -g 1280x854x32
>
> This should give me a PowerMac G4 with the same CPU one can find
> in 15" PowerBook G4.
> But the system does not start. In the console I get only
> > VNC server running on ::1:5900
>
> And one core is used for 100%. Do I connect via vnc I get en maybe
> 640x480 black window which shows the message:
> > Guest has not initialized the display (yet).

This usually means "QEMU is running fine, but the guest has
crashed fatally before it got round to doing anything with
the graphics". In this case the most likely reason is that
your guest is not able to run with the CPU type you're trying
to specify -- in that case the solution would be to use a different
guest image that can boot on this CPU.

It's also possible that QEMU's definition of the 7447a_v1.2
CPU type is just wrong (missing some feature the real hardware
has, perhaps). If you wanted to try to debug this you could
use QEMU's gdbstub and a ppc-aware gdb to debug the guest
to see where it goes wrong, but this is pretty hairy stuff
if you're not familiar with debugging OS/bootloader code.

Why do you care about the exact CPU type here? If the default
one QEMU uses for this machine model works with your guest
image, why not just use it?

thanks
-- PMM