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

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 15/08/18 14:52, Julien Grall wrote:
> 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.

Ok - no problem.  I'll refresh this to just deleting the INVALID case.

~Andrew

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