Re: [Qemu-devel] Just to add one single point

[J. Mayer]

On Mon, 2007-04-09 at 17:26 -0400, Rob Landley wrote:
> On Sunday 08 April 2007 7:19 pm, Paul Brook wrote:
[...]
 
> > AFAIK PPC emulation hasn't *ever* worked well enough to boot without at 
> least 
> > building a custom linux kernel. In addition the -kernel commandline option 
> > have no effect, and there is no test image available.
> 
> By the way, if this ever _does_ start to work, I'd appreciate hearing about 
> it.

It's been working with at least 2.4 kernels for the last 3 years.
The -kernel command used to work. If it does not anymore, it means
someone broke it (and it's not me, I'm absolutely sure but it's been a
very long time I did not test it).
Test images are available. Read the STATUS file to see what I use to
check regressions.
And there are also informations on the Qemu-PPC web page, which is
referenced by the official Qemu site. If one do not find the images, it
seems to me he may not have have searched a lot...

I'm sorry but I _never_ use custom kernels for tests, apart if I want to
add traces to track a really well hiden bug. I always use stock kernels
delivered with distributions or kernels I recompile under Qemu from the
vanilla sources located at kernel.org, with absolutely no patch. Not all
run, that's true. Some may even say that only a few run.

I also know that some binary blurbs (Linux and real-time OSes based) for
embedded PowerPC targets boot and run well under Qemu PPC. Some I
unfortunately cannot release, some I even don't have, just been reported
they run by their owners. Hope I will have some freely available one of
these days.

It also seems that most Linux 2.6 kernels support has been broken. It
used to run too, with some versions having a great problem in
frame-buffer mode (writing black on black is not really usable). Using
the serial console always allowed me to follow the boot until X starts.
It's nowadays broken but it's clearly not my priority to fix this right
now. I'll have to find the issue, but this will wait some time (but no
too long, as the problem may be due to a CPU emulation bug).

As a general statement, it's not my priority to try to find what has
been broken in the hardware emulation for now as I'm working on the
PowerPC core emulation. Those fixes I may track someday for fun but I've
got more urgent things to achieve. I'm sorry for the kiddies that cannot
play with the last Linux distros or Mac OS X but I clearly do not care
about this and feel more important to finish 1/ the targets I want to
emulate (for fun, but not only), 2/ the targets I've been requested to
add (not for fun, this time). The kiddies and Slashdot annoucement
contest may come after, if I got time. But be sure, I would thank anyone
that would try to find and fix those problems in the meantime ! And if
those regression are fixed, be sure I will try to keep those feature
working.

So please, don't say Qemu-PPC does not work. Say some important features
have been broken while changing the Qemu core code without care. But
there is still a sufficient support to test at least Linux running,
installing, compiling, with X11 and most application running well, with
one machine and different CPU models available, which is far from beeing
a "nothing works" statement, imho.
It would be great to have a lot of more machines, CPU, OS, ...
supported. Some things will come, some are the way, but it will take
time. Feel free to suggest things that you feel that should be a
priority, it may give great ideas...

[...]

-- 
J. Mayer <address@hidden>
Never organized