Re: [PATCH v2 12/12] xen/domain: Allocate d->vcpu[] in domain_create()

[Julien Grall <julien.grall@arm.com>]

Hi Andrew,

On 08/15/2018 02:50 PM, Andrew Cooper wrote:
> On 15/08/18 14:17, Julien Grall wrote:
>>>> diff --git a/xen/arch/arm/vgic/vgic.c b/xen/arch/arm/vgic/vgic.c
>>>> index 832632a..4124817 100644
>>>> --- a/xen/arch/arm/vgic/vgic.c
>>>> +++ b/xen/arch/arm/vgic/vgic.c
>>>> @@ -951,27 +951,7 @@ void vgic_sync_hardware_irq(struct domain *d,
>>>>      unsigned int vgic_max_vcpus(const struct domain *d)
>>>>    {
>>>> -    unsigned int vgic_vcpu_limit;
>>>> -
>>>> -    switch ( d->arch.vgic.version )
>>>> -    {
>>>> -    case GIC_INVALID:
>>>> -        /*
>>>> -         * Since evtchn_init would call domain_max_vcpus for poll_mask
>>>> -         * allocation before the VGIC has been initialised, we need to
>>>> -         * return some safe value in this case. As this is for
>>>> allocation
>>>> -         * purposes, go with the maximum value.
>>>> -         */
>>>> -        vgic_vcpu_limit = MAX_VIRT_CPUS;
>>>> -        break;
>>>> -    case GIC_V2:
>>>> -        vgic_vcpu_limit = VGIC_V2_MAX_CPUS;
>>>> -        break;
>>>> -    default:
>>>> -        BUG();
>>>> -    }
>>>> -
>>>> -    return min_t(unsigned int, MAX_VIRT_CPUS, vgic_vcpu_limit);
>>>> +    return min_t(unsigned int, MAX_VIRT_CPUS,
>>>> d->arch.vgic.handler->max_vcpus);
>>>>    }
>>>
>>> Since both implementations are equal now, can you place this in vgic.h
>>> as a static inline function?
>>
>> vgic/vgic.c is part of the new vGIC implementation (selectable at th e
>> compilation time) and using a different layout for the vgic_dist
>> structure. The structure is described in asm/new_vgic.h and does not
>> store the max vcpus anymore.
>>
>> Instead, the switch should be retained and only the case GIC_INVALID
>> should be dropped.
> 
> What about GIC_V3?  VGIC_V3_MAX_CPUS seems to be 255 at the moment.

GICv3 is not yet supported by the new vGIC and disabled at compile time. 
So we should never reach this code with d->arch.vgic.version == GIC_V3.

Cheers,

-- 
Julien Grall

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