Re: [Qemu-devel] [PATCH qom-cpu 0/6] cpu: Unifying features parsing

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 03/05/2014 07:30 PM, Andreas Färber wrote:
> Am 05.03.2014 03:50, schrieb Alexey Kardashevskiy:
>> On 03/04/2014 01:55 PM, Andreas Färber wrote:
>>> Hello,
>>>
>>> Prompted by Alexey's desire for tweakable PowerPCCPU properties but also by
>>> Peter's wish for ARMCPU properties, this series sets out to align cpu_model
>>> parsing across targets.
>>>
>>> QemuOpts would've been nice to use, but on the one hand x86 and sparc use
>>> QemuOpts-incompatible +foo and -foo syntax (which accumulate rather than apply
>>> immediately) and on the other linux-user and bsd-user don't use QemuOpts at all.
>>>
>>> The x86 implementation is closest to the proposed API, save for some laziness.
>>> SPARC is brought in line. And as fallback for the remaining targets a new
>>> implementation, derived from x86 but supporting only key=value format, is added.
>>>
>>> To facilitate using this infrastructure, a generic CPU init function is created.
>>
>>
>> Besides the fact that this patchset does not support dynamic properties
>> (added by object_property_add(), and I used it in my initial patchset),
> 
> Why would that be? I am using QOM object_property_parse() just like on
> x86 where we do have a mix of static and dynamic properties. Maybe you
> are using object_property_add() in the wrong place? It should be used in
> the instance_init function of the CPU - be it PowerPCCPU or a derived
> family/model - i.e. before cpu_ppc_init() returns. The same is necessary
> to support -global.


cpu_ppc_init() calls cpu_generic_init() which does parsing before setting
"realized" to "true". The only way to add a dynamic property here is to put
object_property_add() in ppc_cpu_initfn() but it does not have CPU family
hooks (unlike realizefn). Adding "compat" for every PPC CPU is ... wrong?

Where I tried adding dynamic property before is init_proc_POWER7
(PowerPCCPUClass::init_proc) which is called from init_ppc_proc() which is
called from ppc_cpu_realizefn() and this is too late.


> 
>> that works for SPAPR, just need to implement property statically (tested).
> 
> Thanks,
> Andreas
> 


-- 
Alexey