Re: [Qemu-devel] FPU x86 instructions error

[Andreas Färber]

Hi,

Am 24.05.2013 23:44, schrieb Paolo Bonzini:
> Il 24/05/2013 23:39, Clemens Kolbitsch ha scritto:
>> we recently had an issue with running a program using FPU instructions
>> to obtain the current EIP (basically a weird way of "call 0; pop eax")
>> that was not working on QEMU (with TCG).
>>
>> Looking at the problem, we found this patch to be useful/fixing the issue:
>>
>> https://launchpadlibrarian.net/140457932/patch-qemu-1.5.0-fpip.diff
>>
>> Looking through the DEVEL archives, I found this patch
>>
>> http://lists.nongnu.org/archive/html/qemu-devel/2011-06/msg01206.html
>>
>> that adds the FPU flags to the environment, but is only using them for KVM.
>>
>> I was wondering - since the above patch is rather old, you have
>> probably come across it before - if there was a reason for not
>> including it in QEMU (I checked in git:master and it's not applied).
>> If there isn't, maybe it'd be worth re-considering :)
> 
> For the TCG patch, there is no Signed-off-by and using a helper is not
> necessary.

Clemens, generally we can't just take another person's patch and apply
it - that's what we need the Signed-off-by for. Your post is the only
Google hit for that link and no hits for fpip in my archive - you'll
need to contact the author to obtain her Sob and properly submit it to
qemu-devel - or post a patch yourself that is not based on that one.

http://wiki.qemu.org/Contribute/SubmitAPatch

> For the KVM patch, it simply fell through the cracks, I believe.

It didn't:
http://git.qemu.org/?p=qemu.git;a=commit;h=42cc8fa620cbc73e349e96d84cf46469e828ec34

(I was about to suggest placing the non-TCG fields into X86CPU. :))

Regards,
Andreas

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