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

[Natalia Portillo]

El 21/08/2011, a las 11:04, Laurent Vivier escribió:

> 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] 

As always, at least there are not so many "secret opcodes" :p

> 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.

But bypassing the ROM in all cases is not emulating a real Macintosh,
is creating a special target for Linux that emulates the same hardware.

(Gz for your EMILE, but, buy a tripod :p)

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

Last time I used Executor it only emulated an OS 6 Toolbox and with a 
compatibility scarce at best.

>>>> 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
> 
>