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

[Aurelien Jarno]

On Wed, Oct 31, 2012 at 06:05:57PM +0100, Stefan Weil wrote:
> Am 31.10.2012 00:56, schrieb Aurelien Jarno:
> >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.
> 
> 
> Tested-by: Stefan Weil <address@hidden>
> 
> Your attached patch fixes the problem seen with qemu-system-x86_64
> on 32 bit Linux and with 32 bit Windows.
> 
> I think you can commit it to git master.
> 

Done. Thanks for the test.

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