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

[David Gibson]

On Tue, Oct 01, 2019 at 09:41:27AM +0200, Cédric Le Goater wrote:
> 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'.

Hm, yeah, maybe.  I don't love having a whole structure in there
that's unused when ic-mode != dual.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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