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

[Stefano Stabellini]

On Fri, 11 Sep 2009, Juan Quintela wrote:
> I think we can't call that a regression:
> 
> Old in the past SaveVM State v2 is created.
> 
> Everything works for a while.
> 
> At some later point SaveVM State v3 is created.
> 
> Things continue to work fo a while.
> 
> After this while (In April of this year ram support for V2 got broken, when I 
> fixed
> it, I found that VGA got garbled and ide didn't work either).
> 
> Things didn't work for at least 5 months, I haven't seen a complaint.
> 
> Removing something that hasn't work during 5 months and nobody
> complained is supposed to be a regression?
> 
> Now: We have v2 support on tree, that is not working, haven't worked for
> a long time, and there is not a chance to load an image from the old
> past.  What is better?  Remove the old non working code.  Or spend time
> debugging why it stopped working and fixing it?  Notice that it is also
> important that nobody complained that they were unable to load the old images.
> 

No one complained because the people affected by this issue probably
don't follow qemu development so closely to have realized that their old
images won't work anymore.
I do believe that fixing v2 compatibility is important for a large
number of qemu users (including kvm and xen).

That said, I don't want to fight over this more than necessary, so as
long as you keep the per device loading functions in C we can maintain
v2 compatibility downstream if upstream is not interested.