Re: [Qemu-devel] [RFC PATCH v2 13/15] cpu-model/s390: Add processor property routines

["Andreas Färber" <afaerber@suse.de>]

Am 20.02.2015 um 16:32 schrieb Michael Mueller:
> On Fri, 20 Feb 2015 15:03:30 +0100
> Alexander Graf <agraf@suse.de> wrote:
> 
>>>
>>> - s390_get_proceccor_props()
>>> - s390_set_proceccor_props()
>>>
>>> They can be used to request or retrieve processor related information from an accelerator.
>>> That information comprises the cpu identifier, the ICB value and the facility lists.
>>>
>>> Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>  
>>
>> Hrm, I still seem to miss the point of this interface. What do you need
>> it for?
> 
> These functions make the internal s390 cpu model API independent from a specific accelerator:  
> 
> int s390_set_processor_props(S390ProcessorProps *prop)
> {
>     if (kvm_enabled()) {
>         return kvm_s390_set_processor_props(prop);
>     }
>     return -ENOSYS;
> }
> 
> It's called by:
> 
> s390_select_cpu_model(const char *model)
> 
> which is itself called by:
> 
> S390CPU *cpu_s390x_init(const char *cpu_model)
> {
>     S390CPU *cpu;
> 
>     cpu = S390_CPU(object_new(s390_select_cpu_model(cpu_model)));
> 
>     object_property_set_bool(OBJECT(cpu), true, "realized", NULL);
> 
>     return cpu;
> }
> 
> So above s390_set/get_processor_props() the code is accelerator independent.

Can't you just implement the class-level name-to-ObjectClass callback
that other CPUs have grown for the above use case?

Also a general comment: cpu-model/ is not an existing directory nor one
you add, so please use "target-s390x: Add foo to S390CPU" or so.

Regards,
Andreas

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