Re: [Xen-devel] [PATCH v3 39/39] ARM: VGIC: wire new VGIC(-v2) files into Xen build system

[Andre Przywara <andre.przywara@xxxxxxxxxx>]

Hi,

On 22/03/18 08:16, Julien Grall wrote:
> Hi Andre,
> 
> On 03/21/2018 04:32 PM, Andre Przywara wrote:
>> diff --git a/xen/arch/arm/vgic/vgic.c b/xen/arch/arm/vgic/vgic.c
>> index 131358a5a1..22c70ff7cd 100644
>> --- a/xen/arch/arm/vgic/vgic.c
>> +++ b/xen/arch/arm/vgic/vgic.c
>> @@ -981,6 +981,16 @@ unsigned int vgic_max_vcpus(const struct domain *d)
>>       return min_t(unsigned int, MAX_VIRT_CPUS, vgic_vcpu_limit);
>>   }
>>   +#ifdef CONFIG_HAS_GICV3
>> +void vgic_v3_setup_hw(paddr_t dbase,
>> +                      unsigned int nr_rdist_regions,
>> +                      const struct rdist_region *regions,
>> +                      unsigned int intid_bits)
>> +{
>> +    /* Dummy implementation to allow building without actual vGICv3
>> support. */
> 
> One major inconvenience with that solution is GICv3 driver is going to
> be initialized but then you hit the BUG_ON() in domain_vgic_register.
> This is really not nice for the user but it is not obvious why the
> BUG_ON() is hit.
> 
> I am ok if you don't want to touch the Kconfig. But I would at least
> implement that helper with a panic("vGICv3 not yet supported with the
> new vGIC");

Yes, that's a good point (and easy to implement!) ;-)

Also I think we should have something saying that we are using the new
VGIC, so we have it in the logs. Just realised this when I was wondering
if my machine is currently using the new or the old VGIC ;-)

I put something in the vgic_v2_setup_hw() implementation.

Cheers,
Andre.

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