Re: [PATCH] hw/qdev-core: Add compatibility for (non)-transitional devs

[Jean-Louis Dupond <jean-louis@dupond.be>]

On 19/10/2021 18:56, Eduardo Habkost wrote:
> On Tue, Oct 19, 2021 at 12:13:17PM -0400, Michael S. Tsirkin wrote:
>> On Tue, Oct 19, 2021 at 11:29:13AM -0400, Eduardo Habkost wrote:
>>> On Tue, Oct 19, 2021 at 06:59:09AM -0400, Michael S. Tsirkin wrote:
>>>> On Tue, Oct 19, 2021 at 11:46:17AM +0100, Stefan Hajnoczi wrote:
>>>>> On Tue, Oct 12, 2021 at 10:36:01AM +0200, Jean-Louis Dupond wrote:
>>>>>> Forgot to CC maintainers.
>>>>> Also CCing Jason Wang and Michael Tsirkin for VIRTIO.
>>>>>
>>>>> Stefan
>>>> OMG
>>>> where all compat properties broken all the time?
>>> Compat properties that existed when commit f6e501a28ef9 ("virtio:
>>> Provide version-specific variants of virtio PCI devices") was
>>> merged are not broken, because virtio-*-transitional and
>>> virtio-*-non-transitional were brand new QOM types (so there's no
>>> compatibility to be kept with old QEMU versions).
>>>
>>> Compat properties referencing "virtio-*-pci" instead of
>>> "virtio-*-pci-base" added after commit f6e501a28ef9 are probably
>>> broken, yes.
>>>
>>> -- 
>>> Eduardo
>> Oh. So just this one:
>>      { "virtio-net-pci", "vectors", "3"},
>>
>> right?
> I think so.  That's the only post-4.0 virtio-*-pci compat property I see in
> hw/core/machine.c.
>
> pc.c doesn't have any post-4.0 virtio-*-pci compat props.  I didn't see any
> virtio compat props on spapr.c and s390-virtio-ccw.c.
>
>> about the patch: how do people feel about virtio specific
>> stuff in qdev core? Ok by everyone?
> Not OK, if we have a mechanism to avoid that, already (the
> "virtio-net-pci-base" type name).  I wonder what we can do to
> make this kind of mistake less likely, though.
>
> Jean-Louis, Jason, does the following fix work?
>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index b8d95eec32d..bd9c6156c1a 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -56,7 +56,7 @@ GlobalProperty hw_compat_5_2[] = {
>       { "ICH9-LPC", "smm-compat", "on"},
>       { "PIIX4_PM", "smm-compat", "on"},
>       { "virtio-blk-device", "report-discard-granularity", "off" },
> -    { "virtio-net-pci", "vectors", "3"},
> +    { "virtio-net-pci-base", "vectors", "3"},
>   };
>   const size_t hw_compat_5_2_len = G_N_ELEMENTS(hw_compat_5_2);
>   
That patch fixes it indeed!

Acked-by: Jean-Louis Dupond <jean-louis@dupond.be>