Re: [PATCH v2 21/33] spapr, xics, xive: Move cpu_intc_create from SpaprIrq to SpaprInterruptController

[Cédric Le Goater]

On 01/10/2019 08:47, David Gibson wrote:
> On Tue, Oct 01, 2019 at 07:43:51AM +0200, Cédric Le Goater wrote:
>> On 01/10/2019 04:31, David Gibson wrote:
>>> On Mon, Sep 30, 2019 at 12:13:14PM +0200, Cédric Le Goater wrote:
>>>> On 30/09/2019 08:14, David Gibson wrote:
>>>>> On Mon, Sep 30, 2019 at 07:28:45AM +0200, Cédric Le Goater wrote:
>>>>>> On 30/09/2019 03:49, David Gibson wrote:
>>>>>>> On Fri, Sep 27, 2019 at 12:16:49PM +0200, Greg Kurz wrote:
>>>>>>>> On Fri, 27 Sep 2019 15:50:16 +1000
>>>>>>>> David Gibson <address@hidden> wrote:
>>>>>>>>
>>>>>>>>> This method essentially represents code which belongs to the interrupt
>>>>>>>>> controller, but needs to be called on all possible intcs, rather than
>>>>>>>>> just the currently active one.  The "dual" version therefore calls
>>>>>>>>> into the xics and xive versions confusingly.
>>>>>>>>>
>>>>>>>>> Handle this more directly, by making it instead a method on the intc
>>>>>>>>> backend, and always calling it on every backend that exists.
>>>>>>>>>
>>>>>>>>> While we're there, streamline the error reporting a bit.
>>>>>>>>>
>>>>>>>>> Signed-off-by: David Gibson <address@hidden>
>>>>>>> [snip]
>>>>>>>>> @@ -525,6 +469,30 @@ static void spapr_irq_check(SpaprMachineState 
>>>>>>>>> *spapr, Error **errp)
>>>>>>>>>  /*
>>>>>>>>>   * sPAPR IRQ frontend routines for devices
>>>>>>>>>   */
>>>>>>>>> +int spapr_irq_cpu_intc_create(SpaprMachineState *spapr,
>>>>>>>>> +                              PowerPCCPU *cpu, Error **errp)
>>>>>>>>> +{
>>>>>>>>> +    if (spapr->xive) {
>>>>>>>>> +        SpaprInterruptController *intc = SPAPR_INTC(spapr->xive);
>>>>>>>>> +        SpaprInterruptControllerClass *sicc = 
>>>>>>>>> SPAPR_INTC_GET_CLASS(intc);
>>>>>>>>> +
>>>>>>>>> +        if (sicc->cpu_intc_create(intc, cpu, errp) < 0) {
>>>>>>>>> +            return -1;
>>>>>>>>> +        }
>>>>>>>>> +    }
>>>>>>>>> +
>>>>>>>>> +    if (spapr->ics) {
>>>>>>>>> +        SpaprInterruptController *intc = SPAPR_INTC(spapr->ics);
>>>>>>>>> +        SpaprInterruptControllerClass *sicc = 
>>>>>>>>> SPAPR_INTC_GET_CLASS(intc);
>>>>>>>>> +
>>>>>>>>> +        if (sicc->cpu_intc_create(intc, cpu, errp) < 0) {
>>>>>>>>> +            return -1;
>>>>>>>>> +        }
>>>>>>>>> +    }
>>>>>>>>> +
>>>>>>>>
>>>>>>>> Instead of these hooks, what about open-coding 
>>>>>>>> spapr_xive_cpu_intc_create()
>>>>>>>> and xics_spapr_cpu_intc_create() directly here, like you already did 
>>>>>>>> for the
>>>>>>>> ICS and the XIVE objects in spapr_irq_init() ?
>>>>>>>
>>>>>>> I'd prefer not to.  The idea is I want to treat this as basically:
>>>>>>>
>>>>>>>         foreach_possible_intc(intc)
>>>>>>>                 intc::cpu_intc_create(...)
>>>>>>>
>>>>>>> If I find time I might indeed replace the explicit ics and xive
>>>>>>> pointers with just an array of SpaprInterruptController *.
>>>>>>
>>>>>> Or you could use object_child_foreach() and check for the type. If we had
>>>>>> a helper object_child_foreach_type(), we could use it elsewhere.
>>>>>
>>>>> I thought about that, but I don't think it quite works.  The
>>>>> complication is that the xics device is made explicitly a child of the
>>>>> machine, but the xive device has mmio, so it's a SusBusDevice sitting
>>>>> on the root bus instead.
>>>>
>>>> PnvXscom works fine with Devices and SysBusDevices.
>>>
>>> Uh... what's an example of it working with a SysBusDevice?  All the
>>> implementors of PNV_XSCOM_INTERFACE I could find were instantiated
>>> with object_initialize_child() making them explicitly children of the
>>> chip.  The SPAPR_XIVE is instantiated with qdev_create(NULL,
>>> TYPE_SPAPR_XIVE), making it a child of the root bus, not the machine,
>>> I believe.
>>
>> I see. We should reparent the interrupt controller then.
> 
> Well, maybe.  It's not obvious to me that that's the right approach
> just because of this.
> 
> 
>> Could we rework 
>> the code to instantiate and realize the XICS and XIVE model objects ? 
>> We have the handlers spapr_instance_init() and spapr_machine_init(). 
> 
> I'm not really sure what you're suggesting here.

Define the device model objects under the machine and not pointers :

        struct SpaprMachineState {
                ...
                ICSState ics;
                SpaprXive  xive;
                ...
        };

in spapr_instance_init() :

        object_initialize_child(obj, "ics",  &spapr->ics, sizeof(spapr->ics),
                            TYPE_ICS, &error_abort, NULL);
        object_property_add_const_link(OBJECT(&spapr->ics), "xics", obj,
                                   &error_abort);

        object_initialize_child(obj, "xive",  &spapr->xive, sizeof(spapr->xive),
                            TYPE_SPAPR_XIVE, &error_abort, NULL);


in spapr_machine_init(), call the realize handler depending on the chosen 
'ic-mode'. 


C.


>> That always has been a problem IMO.
>>
>>
>> C. 
>>  
>>
>>
>