Re: [Qemu-ppc] [PATCH v3 07/33] automatically add vmstate for reset support in devices

[Juan Quintela]

Peter Maydell <address@hidden> wrote:
> On Fri, 9 Aug 2019 at 11:29, Damien Hedde <address@hidden> wrote:
>>
>> One way to keep the feature without copy-pasting vmsd would be to add
>> a new vmstate_register with an additional argument to pass the base
>> class vmsd section and handle the whole thing there.
>
> If we have a vmstate section which contains no actual data,
> only subsections with 'needed' functions, is it migration
> compatible with previous versions in the same way that
> tacking a subsection onto an existing function is?

Not now, but we can make it happen.

Right now, we first send the VMSD "header", and then we sent whatever
data is in it.

We can it make work the way you want.  Not sure if that is the best way,
though.  Sections that can(or can't) be there make just reasoning about
the stream more difficult.

Later, Juan.