Re: [patch 33/37] iommu/arm-smmu-v3: Use msi_get_virq()

[Thomas Gleixner]

On Mon, Nov 29 2021 at 13:52, Thomas Gleixner wrote:
> On Mon, Nov 29 2021 at 10:55, Will Deacon wrote:
>> On Sat, Nov 27, 2021 at 02:20:59AM +0100, Thomas Gleixner wrote:
>>> +	smmu->evtq.q.irq = msi_get_virq(dev, EVTQ_MSI_INDEX);
>>> +	smmu->gerr_irq = msi_get_virq(dev, GERROR_MSI_INDEX);
>>> +	smmu->priq.q.irq = msi_get_virq(dev, PRIQ_MSI_INDEX);
>>
>> Prviously, if retrieval of the MSI failed then we'd fall back to wired
>> interrupts. Now, I think we'll clobber the interrupt with 0 instead. Can
>> we make the assignments to smmu->*irq here conditional on the MSI being
>> valid, please?
>
> So the wired irq number is in ->irq already and MSI does an override
> if available. Not really obvious...

But, this happens right after:

     ret = platform_msi_domain_alloc_irqs(dev, nvec, arm_smmu_write_msi_msg);

So if that succeeded then the descriptors exist and have interrupts
assigned.

Thanks,

        tglx