[Qemu-discuss] No start with -cpu option

[Thomas]

Hi!

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).

I waited for about 15 min without changes.

Do I start the same but without the option "-cpu '7447a_v1.2'"
as in:
> qemu-system-ppc -boot d -machine mac99,via=pmu -m 1G -hda root.img -cdrom 
> install-powerpc-minimal-20190720T101002Z.iso -g 1280x854x32

the virtual machine starts. I get a grub boot menu and can start
the LiveCD. Unfortunately it uses the "wrong" cpu 7400_v2.9.

A "qemu-system-ppc -cpu help" lists both CPUs and 405 other. So
7447a_v1.2 should be supported.

My questions:
Why does the machine not start with the -cpu option?
Any tips to get a running machine with the 7447a_v1.2 - cpu?

Thanks in advance
Thomas