Re: [Qemu-devel] [PULL 42/43] piix4: add acpi pci hotplug support

[Anthony Liguori]

On Tue, Oct 15, 2013 at 1:17 PM, Michael S. Tsirkin <address@hidden> wrote:
> On Tue, Oct 15, 2013 at 09:27:33AM -0700, Anthony Liguori wrote:
>> Paolo Bonzini <address@hidden> writes:
>>
>> > Il 15/10/2013 16:35, Michael S. Tsirkin ha scritto:
>> >> On Tue, Oct 15, 2013 at 04:31:31PM +0200, Paolo Bonzini wrote:
>> >>> Il 14/10/2013 17:01, Michael S. Tsirkin ha scritto:
>> >>>> -        VMSTATE_STRUCT(pci0_status, PIIX4PMState, 2, 
>> >>>> vmstate_pci_status,
>> >>>> -                       struct pci_status),
>> >>>> +        VMSTATE_STRUCT_TEST(pci0_status, PIIX4PMState,
>> >>>> +                            vmstate_test_no_use_acpi_pci_hotplug,
>> >>>> +                            2, vmstate_pci_status,
>> >>>> +                            struct pci_status),
>> >>>
>> >>> There's no reason to remove this from the stream when a new machine type
>> >>> is in use.  You'll just send out zeroes.
>> >>
>> >> Seemed cleaner not to.
>> >
>> > It certainly would be if we had a self-descriptive migration stream
>> > format.
>>
>> Yes, removing tests is always a good thing.
>>
>> But I think subsections should always be used when they can.  We should
>> not break compatibility (even if we technical don't guarantee it) unless
>> we absolutely have to.
>>
>> Regards,
>>
>> Anthony Liguori
>
> OK so I can interpret this in 2 ways wrt bridge hotplug:
> - it's in shape for 1.7 except the migration which should use
>   subsections (and needs cross-version testing)
> - it's not in shape for 1.7
>
> Can you tell me which it is please?

The code is not in shape.  Forget about the existence of 1.7.  Focus
on getting the code right and it will make whatever release it is
ready for.  If that's 1.7, great, but the fact that 1.7 is around the
corner does not mean we're going to merge something that isn't ready
just so it makes the release.

Migration is one issue.  As I said before, testing is another.  There
really should be some test automation for this.

Regards,

Anthony Liguori

> If it's 1 I'll repost a version with tweaked
> migration format and cross-version testing report, tomorrow.
>
> If it's 2 I'd rather work on this after the forum, I still
> need to make some travel arrangements.
>
> Paolo? Anthony?
>
> --
> MST