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SubjectRe: [PATCH v6 10/29] iommu/vt-d: Implement minor tweaks for NMI irqs
Date
On Thu, May 05 2022 at 16:59, Ricardo Neri wrote:
> The Intel IOMMU interrupt remapping driver already programs correctly the
> delivery mode of individual irqs as per their irq_data. Improve handling
> of NMIs. Allow only one irq per NMI. Also, it is not necessary to cleanup
> irq vectors after updating affinity.

Structuring a changelog in paragraphs might make it readable. New lines
exist for a reason.

> NMIs do not have associated vectors.

Again. NMI has an vector associated, but it is not subject to dynamic
vector management.

> diff --git a/drivers/iommu/intel/irq_remapping.c b/drivers/iommu/intel/irq_remapping.c
> index fb2d71bea98d..791a9331e257 100644
> --- a/drivers/iommu/intel/irq_remapping.c
> +++ b/drivers/iommu/intel/irq_remapping.c
> @@ -1198,8 +1198,12 @@ intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask,
> * After this point, all the interrupts will start arriving
> * at the new destination. So, time to cleanup the previous
> * vector allocation.
> + *
> + * Do it only for non-NMI irqs. NMIs don't have associated
> + * vectors.

See above.

> */
> - send_cleanup_vector(cfg);
> + if (cfg->delivery_mode != APIC_DELIVERY_MODE_NMI)
> + send_cleanup_vector(cfg);

So this needs to be replicated for all invocations of
send_cleanup_vector(), right? Why can't you put it into that function?

> return IRQ_SET_MASK_OK_DONE;
> }
> @@ -1352,6 +1356,9 @@ static int intel_irq_remapping_alloc(struct irq_domain *domain,
> if (info->type == X86_IRQ_ALLOC_TYPE_PCI_MSI)
> info->flags &= ~X86_IRQ_ALLOC_CONTIGUOUS_VECTORS;
>
> + if ((info->flags & X86_IRQ_ALLOC_AS_NMI) && nr_irqs != 1)
> + return -EINVAL;

This cannot be reached when the vector allocation domain already
rejected it, but copy & pasta is wonderful and increases the line count.

Thanks,

tglx


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