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

[J. Mayer]

On Thu, 2007-03-22 at 12:39 -0500, Jason Wessel wrote:
> Attached is a patch as well as an example program, where I took the code 
> from the from the linux kernel and made a call in with a dummy packet.
> 
> It appears the problem is the addic translation does not correctly 
> set/reset the carry bit, and this is a regression vs the source base on 
> 3/7/2007.  With the change here, I can boot the ppc-prep machine again 
> and use ethernet.

OK, thanks for this detailed report, I can now see what the bug is: the
carry should be reset when immediate value is zero.
Your patch is not great because it disables useful optimization, but I
will test another one and commit it soon.

> 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.
> >

-- 
J. Mayer <address@hidden>
Never organized