[Qemu-devel] Re: testing qemu svn r6636 on FreeBSD; future of qemu on FreeBSD...

[Gary Jennejohn <gary.jennejohn@freenet.de>]

On Mon, 23 Feb 2009 22:19:33 +0100
Juergen Lock <nox@jelal.kn-bremen.de> wrote:

> On Mon, Feb 23, 2009 at 03:47:24PM +0100, Gary Jennejohn wrote:
> > On Sun, 22 Feb 2009 02:37:47 +0100
> > Juergen Lock <nox@jelal.kn-bremen.de> wrote:
> > 
> > > been experimental and you should use raw images if you want reliability;
> > > raw is also usually faster) - apart from these two issues this snapshot
> > > is looking pretty good in my (limited) testing so far; you are encouraged
> > > to test it with your various guests that you have lying around, if it
> > > works for you as well maybe we can indeed update the FreeBSD qemu-devel
> > > port again before the next official qemu release gets cut...
> > > 
> > 
> > Well, I applied the patches and installed qemu.
> > 
> > I tried installing openSUSELinux 10.3 because I had a DVD laying around.
> > 
> > I used a 150GB raw image created using qemu-img.  I did not use kqemu.
> > I started qemu with this command line:
> > 
> > qemu -boot d -cdrom /dev/acd0 -hda linux.img -localtime -m 1G
> > 
> > Note I have an AMD64 X2 with 4GB of RAM installed running 8-current.
> > 
> > It got up to the point where it actually started the install and then
> > croaked with SIGSEGV, I think it was.  The error message flashed by
> > rather quickly.
> > 
> > That means that I was able to partition the disks and specify some
> > non-standard packages. It managed to create and format the disk
> > partitions and figure out from the DVD which packages to install.
> > 
> > Not too bad, I suppose.
> 
> A SIGSEGV, hmm.  What I do see sometimes especially without kqemu is guest
> failures related to various kinds of timeouts, i.e. guests not expecting
> running as slowly...  tho a SIGSEGV is probably something different.
>

I tried the installation a few more times using the patched qemu-devel
and was able to see that the error was indeed a segmentation violation
in Yast.call, whatever that may mean.

> You could try a few things:
> a) the same with kqemu (userland), in case its a tcg bug (or indeed a
>    timeout; remember to rebuild qemu in case you built it without the
>    kqemu knob enabled or otherwise kqemu won't get used), and also
> b) another time with -kernel-kqemu in case its a tcg bug affecting
>    guest kernel code (altho of course in both cases kqemu can cause its
>    own kind of failures, even more so with amd64 guests...)
>

I'll consider doing these steps with the patched qemu-devel later.

> c) try the same with the original qemu-devel port and also with qemu 0.9.1
>    (the qemu port), in case its a regression (possibly caused by the tcg
>    conversion?)
>

qemu never gets past the initial openSUSE install screen.  It just sits
there eating 100% of the CPU without any visible progress.

I tried qemu-devel with kqemu.ko loaded but it never got past loading the
Linux kernel.  It hung at various boot stages with no apparent pattern.

Without kqemu.ko it is actually doing the install as I write this.  Have
to wait and see just how far it gets.

One difference between now and before is that I have vfs_aio in the
kernel.  I'm also running a brand-new kernel from today.

BTW this is the command line which I used:
qemu -net none -m 1G -boot d -cdrom /dev/acd0 -hda linux.img -localtime -std-vga

> d) see if you can enable coredumps in the guest in order to find out more
>    about your particular failure.
> 

Well, supposedly Yast.call dumped core, but since the Linux install runs
out of a memory disk there's no way for me to see it.

I have no idea how to enable coredumps such that I can acccess any coredumps
which may be made.

>  Oh and if you do any of these you may want to also Cc the qemu list with
> your findings, they are probably interested as well...
> 

OK, added.

---
Gary Jennejohn