On Jan 27, 2018, at 5:50 PM, BALATON Zoltan
On Sat, 27 Jan 2018, Jd Lyons wrote:
> As I stated, the 7448 was used in upgrade cards for a Powermac G4, and the PDF I
linked says OS 9.2.2 or 10.3.5 or later. The point is Qemu
It also says a firmware patch is needed too. I wonder what those patches do but this
suggests an unpatched OS X would not boot without some additional things.
For whatever reason, the 7448 boots and work just fine with the hypervisor, and TCG mode.
Tho I did note that Altivec doesn’t seem to work, but I only tested SkidmarksGT, so more
testing is needed.
> builds for PowerPC too, and I’d like to use -enable-kvm -cpu host on my Powerbook6,8
with 7447a, my iBook6,7 with 7447a, and my Quicksilver with 7450/7455, but these CPU’s
can’t boot OS X in qemu.
Do you mean it does not boot when you're using QEMU with kvm on
those CPUs or when you try to boot with an emulated 7447a CPU with TCG (no kvm)? These may
be two different cases and I'm not sure which one you've tested.
I’m unable to boot openbios on TCG with the 7447a, 7450, 7455, or the 750fx, even tho I’ve
added support for them. Not sure the issue there.
However Openbios will boot with KVM with the -cpu 7447a, 7450, and 7455. Not the 750fx, I
have an old iBook with a 750fx, just got done putting a HD in it, so I’ll be installing
Linux to see if KVM works, I read that the G3 should support KVM, I just don’t know if KVM
support the G3.
With the 7450/7455( —enable-kvm -cpu 7450/7455 ), even with KVM, they can’t boot the Linux
Kernel from the Debian 8.10 installer.
Seems to fail the same way BootX fails, at the point where the “jump” to the machine
booting the kernel, meaning where the kernel should take over.
With the 7447a ( -enable-kvm -cpu 7447a ), boots the linux kernel and proceeds to the
installer. Never installed it, but I have no reason to believe that it won’t work after
With -enable-kvm -cpu host, Debian install, runs and boots fine, no issues, other than the
L2 cache is not active, but that an issue with openbios, and I’m not sure how to deal with
that yet. Maybe just enable it in software while the OS is running, maybe add the code to
Openbios, that if it detects the hypervisor it should enable the L2/L3.
All the test were done on my Powerbook6,8 with 7447a.
> Why would we want an emulator that supports a wide range of
CPU’s, used in real Macs, that only boots a few of them.
The Mac emulation in QEMU is far from perfect. In fact what it emulates is not even a
real Mac just some random hardware that resembles a PowerMac enough that with some
combinations some OS X versions work more or less. But if you wander off these tried path
problems are expected as probably no-one have tried that yet or haven't fixed it yet.
There's a lot to improve and your effort in this is greatly appreciated, I'm just
saying that it's not expected to be ready and working with all the processors even if
those appear in the list of emulated CPUs as you've already found.
On that note, my patch to qemu for 7447a v1.5 is incomplete, it doesn’t show up in the
list of CPU’s when I invoke -cpu help, and I can’t chose -cpu 4747a_v1.5.
Do you know where in the sconce code that list is propagated, I need to patch that too?
But back to the problem, from your previous messages it seems it booted with a kernel
that disabled the check for unknown CPUs so the problem seems to be that the kernel cannot
recognise the CPU as supported or it tries to do something for these CPUs that does not
work as expected in QEMU. You may need to check what the mach_kernel does after started by
BootX and how it detects the CPU and if it would accept the CPU you've specified
(maybe it would with 7447a which was used in Macs but for 7448 I would not expect that).
The start.s you've linked seems to be the processor detection that runs. Maybe you
could try to enable the -d in_asm debug option of QEMU that prints what guest code it runs
and try to correlate that to the mach_kernel source to find what it does and where it
How would I enable -d in the in_asm debug options?
Is it a runtime option, or do I need to enable it when I build?
Thanks Balaton, I do appreciate your help and input.