Re: [Qemu-devel] Re: Qemu PPC ethernet checksum bug

[Jason Wessel <jason.wessel@windriver.com>]

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J. Mayer wrote:
> Hi,
>
> My concern is I cannot reproduce your problem for the following reasons:
> - the PREP machine (and the heathrow too...) is broken and cannot even
> boot. PCI and/or IRQ are broken, so the Linux kernel hangs.
> - when using the "known to work" Linux distributions on the mac99
> machine (please take a look at the STATUS file), I am able to download a
> kernel from www.kernel.org, which makes me think TCP packets are sent
> and received correctly, with valid checksums.
>
> Then, it would be a great thing if you could isolate the failing routine
> and, for example, make a test case usable with linux-user emulation.
> This would be a great help to solve this issue.
>
> Thanks by advance.
>
>   

Attached is a test program which demonstrates the issue.  You can run
% ./ppc-linux-user/qemu-ppc /tmp/csum_test/main
Testing
Result 0x956a3263

Above is the correct result prior to 3/8/2007.  If you run from CVS 
today, you get
% ./ppc-linux-user/qemu-ppc /tmp/csum_test/main
Testing
Result 0x956a3264


It appears to be a result of the corruption of the xer_ca by the time 
you do the first adde instruction.  

Thanks,
Jason.

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