Re: [Qemu-devel] [RFC][PATCH 000/111] QEMU m68k core additions

[Laurent Vivier]

Le samedi 20 août 2011 à 18:42 -0500, Rob Landley a écrit :
> On 08/20/2011 06:17 PM, Natalia Portillo wrote:
> >> or ancient macintosh support
> > 
> > Most of the hardware (but a few required ones like SWIM) is already
> > in QEMU, you need to glue everything, make Toolbox be VERY happy
> > about its environment, make Mac OS boot so it can second-boot Linux
> > (the direct-booter is so buggy it may introduce phantom bugs on the
> > emulation) and implement the MMU.
> 
> I haven't got a copy of ancient MacOS.
> 
> Why is the direct booter buggy?  I'm happy to track down and isolate
> phantom bugs, either in the kernel or in qemu.  (One nice thing about
> emulators is you can get deterministic regression tests reasonably
> easily. :)
> 
> How do I _use_ the direct booter, anyway?  I built mac_defconfig in 3.0
> but it only gave me a vmlinux, which faulted on the instruction at
> address 0.  I tried m68k-objdump -O binary vmlinux vmlinux.bin but that
> wouldnt' bot at all (qemu -kernel refused to load it).

For the moment, q800 is not working. 

Master branch is for m68k-linux-user target.

I'm working on m68k-softmmu on the macrom-branch by porting the
basiliskII stuff.
[Natalia: this allows me to debug the CPU by comparing traces from
BasiliskII and traces from qemu, I've found several in supervisor mode] 

but a ROM will not be required to boot it as the bootloader has the role
to collect information from the ROM to pass it the kernel.
Qemu will be able to do it and boot directly the kernel (with option
--kernel). We can cut&paste parts from the EMILE bootloader.

A real machine emulation will require a ROM. But for this part we can
have a look to executore (https://github.com/ctm/executor).

> >> that Linux could boot on?  (I.E. I'm interested in Linux system 
> >> emulation of non-coldfire m68k.  So far that means "use aranym".)
> > 
> > Linux requires the MMU and an almost complete hardware emulation. 
> > Standard m68k emulations (UAE, Aranym and specially BasiliskII) try
> > to patch the OS to work.
> 
> That's kinda sad.  Is there a web page anywhere that elaborates on this?
> 
> > Indeed BasiliskII is anything but a real macintosh emulator, as it
> > patches heavily the Toolbox and Mac OS (that's why Linux and A/UX
> > will never work on it)
> 
> I believe toolbox is the ancient mac bios, correct?  Does Linux need/use
> it at all?

No

Regards,
Laurent