Re: [Qemu-devel] [RFC] New Migration Protocol using Visitor Interface

[Michael S. Tsirkin]

On Sun, Oct 02, 2011 at 04:21:47PM -0400, Stefan Berger wrote:
> 
> >4) Implement the BERVisitor and make this the default migration protocol.
> >
> >Most of the work will be in 1), though with the implementation in this 
> >series we should be able to do it incrementally. I'm not sure if the best 
> >approach is doing the mechanical phase 1 conversion, then doing phase 2 
> >sometime after 4), doing phase 1 + 2 as part of 1), or just doing VMState 
> >conversions which gives basically the same capabilities as phase 1 + 2.
> >
> >Thoughts?
> Is anyone working on this? If not I may give it a shot (tomorrow++)
> for at least some of the primitives... for enabling vNVRAM metadata
> of course. Indefinite length encoding of constructed data types I
> suppose won't be used otherwise the visitor interface seems wrong
> for parsing and skipping of extra data towards the end of a
> structure if version n wrote the stream and appended some of its
> version n data and now version m < n is trying to read the struct
> and needs to skip the version [m+1, n ] data fields ... in that case
> the de-serialization of the stream should probably be stream-driven
> rather than structure-driven.
> 
>    Stefan

Yes I've been struggling with that exactly.
Anthony, any thoughts?


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MST