Re: [PATCH] ppc/spapr: fix default cpu for pre-10.0 machines.

[Harsh Prateek Bora <harshpb@linux.ibm.com>]

On 3/12/25 15:50, Harsh Prateek Bora wrote:
> 
> 
> On 3/12/25 15:39, Philippe Mathieu-Daudé wrote:
>> On 12/3/25 06:58, Harsh Prateek Bora wrote:
>>> When POWER10 CPU was made as default, we missed keeping POWER9 as
>>> default for older pseries releases (pre-10.0) at that time.
>>> This caused breakge in default cpu evaluation for older pseries
>>> machines and hence this fix.
>>>
>>
>> Should we also include:
>>
>>    Cc: qemu-stable@nongnu.org
>>
>> ?
>>
> 
> I guess so. Not sure if we need a patch v2 for just that.
> 
>>> Fixes: 51113013f3 ("ppc/spapr: change pseries machine default to 
>>> POWER10 CPU")
>>> Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
>>> ---
>>>   hw/ppc/spapr.c | 1 +
>>>   1 file changed, 1 insertion(+)
>>>
>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>> index c15340a58d..b31a91e2e2 100644
>>> --- a/hw/ppc/spapr.c
>>> +++ b/hw/ppc/spapr.c
>>> @@ -4748,6 +4748,7 @@ static void 
>>> spapr_machine_9_2_class_options(MachineClass *mc)
>>>   {
>>>       spapr_machine_10_0_class_options(mc);
>>>       compat_props_add(mc->compat_props, hw_compat_9_2, 
>>> hw_compat_9_2_len);
>>> +    mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power9_v2.2");
>>
>> This is confusing because v9.2 has already been released with that...
> 
> I think it still needs to be fixed for v9.2 (and older) if someone wants 
> to use pseries-9.2 (and older) with future releases.

Gave it another thought. May be moving the default to v9.1 could be
relatively better. 9.2 stable shall get the fix for pre-9.2 but 9.2
default need not change.

Nick, Daniel, comments?

Thanks
Harsh
> 
> Thanks
> Harsh
> 
>>
>>>   }
>>>   DEFINE_SPAPR_MACHINE(9, 2);
>>
>>
>