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

[Stefan Berger]

> 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