Re: [Qemu-devel] Kqemu on x86_64 host with x86_64 guest

[Julian Seward <jseward@acm.org>]

On Saturday 13 October 2007 16:24, Werner Dittmann wrote:
> Bruno Cornec wrote:
> > On Sat, Oct 13, 2007 at 01:53:37PM +0200, Bruno Cornec wrote:
> >> However, mandriva 2008.0 x86_64 doesn't exhibit this error on the same
> >> host.
> >
> > I stand corrected. It also crashed but later during the install process,
> > where the other were at the start. Back to -no-kqemu.
> >
> > Bruno.
>
> Even when using -no-kqemu it somehow fails/hangs during setup of Grub
> when I try to install a openSuse 10.2 or 10.3 . These problems are know
> for quite some time - but no solution yet.

Yes.  I also observed that with openSUSE 10.{1,2,3}.  After some
experimentation I successfully installed 10.1 by asking the installer
to use LILO instead of Grub.  However, even then, some user space
code does not work properly - running the YaST online update inside the
successfully-installed 10.1 fails.

I wondered if there is some problem in the x86_64 instruction set emulation.
I ran some tests from Valgrind, and it appears that some FP->int conversion
instructions do not take care of the rounding mode.  I did not detect
any other errors.  See
http://lists.gnu.org/archive/html/qemu-devel/2007-10/msg00233.html

I tried to build x86_64-softmmu using softfloat.c rather than
softfloat-native.c since it looks like softfloat.c emulates these
corner cases (rounding mode, etc) more completely.  So far I got 
a lot of compilation errors and did not make much progress.  I get
the impression x86_64-softmmu and i386-softmmu are intended only to
be built with softfloat-native.c.

It might be worth installing SuSE 10.1 and finding some small program
which fails to work properly.  Then we might have a hope of determining
what the problem is.

J