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Re: [Xen-devel] [PATCH][qemu-xen] Change tap device mac address to preve

To: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH][qemu-xen] Change tap device mac address to prevent change of bridge's mac
From: Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
Date: Wed, 5 Jan 2011 23:43:38 +0000
Cc: Miroslav Rezanina <mrezanin@xxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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Ian Campbell writes ("Re: [Xen-devel] [PATCH][qemu-xen] Change tap device mac 
address to prevent change of bridge's mac"):
> On Tue, 2010-12-21 at 13:13 +0000, Miroslav Rezanina wrote:
> > Qemu tap device is created with random mac address and then add to bridge. 
> > Due to linux kernel handlig, bridge change its mac address to tap mac in 
> > case tap mac is lower than bridge one. This can lead to short network 
> > breakage for dom0 and guests. 
> > 
> > This patch set tap device mac adress to FE:FF:FF:FF:FF:FF to ensure tap 
> > device mac is always higher then bridge one.
> > 
> > Signed-off-by: Miroslav Rezanina <mrezanin@xxxxxxxxxx>
> Thanks. This needed a different fix in xen-unstable.hg because tap
> devices are handled by the hotplug scripts and not qemu-ifup there. See
> the recent thread "tools/hotplug/Linux: Ensure tap devices receive a
> dummy MAC address".
> My backport to xen-4.0-testing looked a lot like yours.

Thanks for that, I've applied Miroslav's patch to


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