Re: [Qemu-devel] 64-on-32 TCG broken

[Aurelien Jarno <aurelien@aurel32.net>]

On Wed, Oct 31, 2012 at 12:56:36AM +0100, Aurelien Jarno wrote:
> On Tue, Oct 30, 2012 at 11:24:34PM +0100, Stefan Weil wrote:
> > Am 30.10.2012 09:15, schrieb Paolo Bonzini:
> > >Il 29/10/2012 19:29, Aurelien Jarno ha scritto:
> > >>On Mon, Oct 29, 2012 at 06:53:14PM +0100, Paolo Bonzini wrote:
> > >>>>Known-good commit: 8473f377393219390ea6f2d8d450a2b054bb823e
> > >>>>Known-bad commit: d262cb02861dd33375c08fc798930653b14769e9
> > >>>>
> > >>>>i386-softmmu seems to work.  I may try to bisect it tomorrow, but I'd be
> > >>>>glad if somebody else beats me.  It can be reproduced with Wine and
> > >>>>"x86_64-softmmu/qemu-system-x86_64.exe -L ../pc-bios"; it hangs at iPXE.
> > >>Oops, sorry about that. Is it win32 or win64? I'll try to fix it asap,
> > >>but right now I don't have a good network connection enough to either
> > >>setup a mingw build environment or to connect to a remote machine with
> > >>such an environment.
> > >
> > >It's win32, and the first bad commit is 9c43b68 (tcg: rework liveness
> > >analysis, 2012-10-09).  But it looks like 64-on-32 emulation is more
> > >generally broken.  I now tried x86_64-linux-user compiled for 32-bit,
> > >and it segfaults on startup.  Even the previous commit cannot run
> > >qemu-x86_64 /bin/ls correctly:
> > >
> > 
> > I just tested with latest qemu-system-x86_64 on 32 bit Linux.
> > 
> > It also hangs during boot (BIOS), so it looks like this
> > is not a MinGW only problem.
> > 
> > Your test with x86_64-linux-user indicates that, too.
> > 
> > I also get the problem with TCI. Therefore I expect that any
> > 32 bit TCG target will show it.
> > 
> 
> It ended up to be a merge issue. The newly added special cases
> for half-dead operations also need to be changed with the liveness
> analysis rework.
> 
> The attached patch fixes the issue on a 32-bit linux host. I haven't
> tried win32 yet, maybe someone will beat me.
> 

I have just been able to try, and I confirm it fixes the problem on
win32.

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net