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[Xen-devel] checksum offloading not disabled properly in response to 'fe

To: "xen-devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] checksum offloading not disabled properly in response to 'feature-no-csum-offload'
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Wed, 9 Jan 2008 23:28:45 +1100
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Thread-topic: checksum offloading not disabled properly in response to 'feature-no-csum-offload'
I think I've finally tracked down the problem I'm having with the PV
windows drivers.

Even though I set 'feature-no-csum-offload', and ethtool -k shows that
it is off, wireshark in the windows domU says that the checksums are
bad, until I issue the 'ethtool -K vifX.0 tx off' command, and then it
all comes good. I suspect that Linux is disabling the feature without
actually disabling the function...

I haven't done enough testing yet to properly confirm this, but I'm
reasonably confident that this is the problem.

Anyone seen anything like this before?

Ideally, I'd be able to convince Windows to not look at the received
checksum, but even though I seem to be enabling all the right things and
setting all the right flags, Windows won't listen.

James

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