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Re: [Xen-devel] [PATCH] have architectures specify the number of PIRQs a hardware domain gets



On 05/12/14 14:42, Ian Campbell wrote:
> On Fri, 2014-12-05 at 14:36 +0000, Julien Grall wrote:
>> Hi,
>>
>> On 05/12/14 14:27, Ian Campbell wrote:
>>> On Fri, 2014-12-05 at 13:51 +0000, Jan Beulich wrote:
>>>>  #define nr_static_irqs NR_IRQS
>>>> +#define arch_hwdom_irqs(domid) NR_IRQS
>>>
>>> FWIW gic_number_lines() is the ARM equivalent of getting the number of
>>> GSIs.
>>>
>>> *BUT* we don't actually use pirqs on ARM (everything goes via the
>>> virtualised interrupt controller). So maybe we should be setting
>>> nr_pirqs to 0 on ARM. I appreciate you likely want such a patch to come
>>> from an ARM person, so I'm fine with you making this NR_IRQS in the
>>> meantime.
>>
>> As we already know that PIRQ is not used on ARM, it would make sense to
>> use directly in this patch 0.
> 
> Are you offering to give a tested-by if Jan posts such a patch?

nr_pirqs is used in 2 different place (without counting this setting):
        - event channel => We don't care on ARM as alloc_pirq_struct is
returning NULL
        - XEN_DOMCTL_irq_permission => I don't really understand this bits.
AFAIU the pirq number is different on each domain. But we use it to
check permission on both domain. Shouldn't we translate the pirq to irq
for the current->domain?

Regards,

-- 
Julien Grall

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