Re: [Qemu-ppc] [Qemu-devel] [QEMU PATCH v5 3/6] migration: extend VMStateInfo

[Paolo Bonzini]

On 12/10/2016 13:59, Halil Pasic wrote:
> IMHO this would:
> * allow us to keep the good old MVStateInfo objects unmodified and
>   the semantic of VMStateInfo unchanged
> * make clear that VMStateLinked does not care about the calculated size
>   and provide a new anchor for documentation
> * if overloading the semantic of VMStateField.start is not desired we
>   could put it into  VMStateLinked, if needed we could also put more
>   stuff in there
> * have clearer separation between special handling for (linked/certain)
>   data structures and the usual scenario with the DAG.

No, I disagree.  We shouldn't be worried about making intrusive changes
to all invocations or declarations, if that leads to a simpler API.

I agree that overloading .start can be a bit ugly but you can choose to
overload .num_offset instead, which is already better.

> I would also suggest unit tests in test/test-vmstate.c. Maybe with
> that the vmstate migration of QTAILQ could be factored out as a separate
> patch series.

Yes, definitely.

Paolo