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Re: [Xen-devel] xen.git branch reorg

To: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] xen.git branch reorg
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Mon, 27 Apr 2009 12:46:53 -0700
Cc: "bderzhavets@xxxxxxxxx" <bderzhavets@xxxxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Christophe Saout <christophe@xxxxxxxx>, Pasi
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Ian Campbell wrote:
My guess would be the change from
CHECKSUM_{HW,etc}+skb->proto_{csum,data}_valid to
CHECKSUM_{UNNECESSARY,PARTIAL,etc} is incomplete/incorrect. This should
be taken care of by f4f969ffe1d9326ccaace768bde3b33a5ae49e71. I saw
checksum offloading issues early on when I did this but I thought I got
it right eventually, I'm pretty certain it was OK for me at the time at

It looks like the checksum is a secondary issue. My understanding is that things like TSO, USO, LRO, etc, depend on hardware checksumming, so disabling checksumming will implicitly disable the large segment features too. And judging from Christophe's report, it seems that's the issue, with unexpectedly large packets appearing in dom0.


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