Re: [Qemu-devel] [PATCH v2 2/4] spapr: Use DeviceClass::fw_name for device tree CPU node

[Alexander Graf]

On 30.08.2013, at 15:58, Andreas Färber wrote:

> Am 30.08.2013 15:53, schrieb Alexey Kardashevskiy:
>> On 08/30/2013 11:26 PM, Andreas Färber wrote:
>>> Am 30.08.2013 15:21, schrieb Alexander Graf:
>>>> 
>>>> On 16.08.2013, at 00:35, Andreas Färber wrote:
>>>> 
>>>>> Instead of relying on cpu_model, obtain the device tree node label
>>>>> per CPU. Use DeviceClass::fw_name when available. This implicitly
>>>>> resolves address@hidden node labels for those CPUs through inheritance.
>>>>> 
>>>>> Whenever DeviceClass::fw_name is not available, derive it from the CPU's
>>>>> type name and fill it in for that class with a "PowerPC," prefix for
>>>>> PAPR compliance.
>>>> 
>>>> Could we just mandate the fw_name field to always be set for all classes 
>>>> instead?
>>> 
>>> Sure, we can assert it. But we would then need to set fw_name for the
>>> various 970 families at least, which I have been using with pseries in
>>> the past. Cell and POWER6 are TODO so I'm not concerned about them. Not
>>> sure about RS64 that Alexey mentioned - I wouldn't be able to test.
>>> Would be bad to regress and abort with CPU models that were working okay
>>> before.
>> 
>> If we generated fw_name as it would have been done by the current helpers,
>> how would anything regress?
> 
> Well, before, you were talking about assigning "reasonable fw_name
> values", and that would for me require knowledge of which value is
> reasonable (i.e., correct) for a certain CPU, and I don't have boards to
> check most of them.
> 
> My proposal would be to just do it for the sPAPR-compatible (not sure if
> that is what you meant with "supported"?) CPUs (because that's where we
> intend to use it) and mark the ones we don't know exactly with /* ??? */
> as done elsewhere in ppc code.

Yup, we could even specifically just name them fw_name = "PowerPC,UNKNOWN"; 
whenever we don't know better as you were suggesting earlier.


Alex