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Date: Mon, 23 Nov 2009 10:26:59 +0200
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [Qemu-devel] Re: Live migration protocol, device features,
	ABIs and   other beasts
Message-ID: <20091123082659.GC2999@redhat.com>
References: <4B0952C9.9010803@redhat.com> <4B095D86.700@codemonkey.ws>
	<hec6i6$j3r$1@ger.gmane.org> <4B09F0CA.3060705@codemonkey.ws>
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org

On Sun, Nov 22, 2009 at 08:17:46PM -0600, Anthony Liguori wrote:
> Paolo Bonzini wrote:
> >
> >>I don't see how this fixes anything. If you used feature bits, how do
> >>you migrate from a version that has a feature bit that an older version
> >>doesn't know about? Do you just ignore it?
> >
> >I'd go with chunk instead of feature bits, specifying them like in
> >the PNG specification:
> 
> You mean, each device would have multiple sections?  We already use
> chunks for each device state.
> 
Each device can send device info in multiple formats (each format with
its own ID) and destination will choose the one it supports.

--
			Gleb.