Re: [Qemu-ppc] [PATCH v4 03/20] ppc/pnv: add a core mask to PnvChip

[David Gibson]

On Wed, Oct 12, 2016 at 10:53:12AM +0200, Cédric Le Goater wrote:
> On 10/11/2016 12:24 PM, David Gibson wrote:
> > On Mon, Oct 10, 2016 at 02:56:25PM +0200, Cédric Le Goater wrote:
> >>
> >>>> @@ -227,11 +227,44 @@ static void ppc_powernv_init(MachineState *machine)
> >>>>          snprintf(chip_name, sizeof(chip_name), "chip[%d]", 
> >>>> CHIP_HWID(i));
> >>>>          object_property_add_child(OBJECT(pnv), chip_name, chip, 
> >>>> &error_fatal);
> >>>>          object_property_set_int(chip, CHIP_HWID(i), "chip-id", 
> >>>> &error_fatal);
> >>>> +        object_property_set_int(chip, smp_cores, "nr-cores", 
> >>>> &error_fatal);
> >>>> +        /*
> >>>> +         * We could customize cores_mask for the chip here. May be
> >>>> +         * using a powernv machine property, like 'num-chips'. Let the
> >>>> +         * chip choose the default for now.
> >>>
> >>> I don't think you need any special mechanism for this.  If you just
> >>> remove this explicit assignment the chip default will apply, but the
> >>> user can alter it using -global.
> >>
> >> Using a command line with :
> >>
> >>    -global powernv-chip-POWER8.cores-mask=0x7070
> >>
> >> would work for one chip but not for more. Let's start with that, I will 
> >> remove the comment for now. multiple chip is for later.
> > 
> > Well, it works for more than one chip if you want the same mask for
> > each of them.  If you want different masks, I think you can still do
> > it with -set, but working out the right arguments can be a PITA.
> 
> That would be the best solution but I did not find a way to address one
> chip object to do a "qom set".

Yeah, that's what I mean working out the arguments can be tricky.

> 
> (qemu) info qom-tree 
> /machine (powernv-machine)
>   /unattached (container)
>     /system[0] (qemu:memory-region)
>     /sysbus (System)
>     /ppc_powernv.ram[0] (qemu:memory-region)
>     /io[0] (qemu:memory-region)
>   /peripheral-anon (container)
>   /peripheral (container)
>   /chip[1] (powernv-chip-POWER8)
>     ...
>   /chip[0] (powernv-chip-POWER8)
>     ...
>  
> We will have a similar need with the ram to spread the contents on
> the chips. 

Sure.  Let's cross these bridges when we come to them.

-- 
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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