Re: [Qemu-devel] Re: [PATCH 03/26] Remove SaveVM v2 support

[Stefano Stabellini]

On Thu, 10 Sep 2009, Anthony Liguori wrote:
> Practically speaking, we only have the ability to support back to 
> 0.10.0.  We simply didn't have the necessary infrastructure in place to 
> support anything older than that.
> v3 of the savevm protocol came before 0.10.0 so there's no need for us 
> to every support v2 or v1 of the protocol.
> 
> There are some major changes happen to the savevm infrastructure for 
> 0.12.0.  I'd suggest that instead of not removing v2, we remove it, 
> finish up the changes, then you can look at re-adding support for it.
> 
> Some of the features of v2 may be difficult to carry forward (like the 
> savevm section sizes).
> 
> And FWIW, I don't necessarily think we'll see a v4 for 0.12.0.  I'm not 
> convinced it's needed and/or useful.
> 

I gave a better look at the code and the situation is not as bad as I
thought: the important code for us is not much the single
function qemu_loadvm_state_v2 that can easily be replaced and\or
rewritten but all the per device state loading functions in C, that
fortunately are shared between v2 and v3.
I am still unhappy with removing support for v2 and I am inclined to
consider it a regression but as long as you keep those functions in I am
reasonably happy.