Feng Wu wrote on 2014-12-12:
> We don't need to migrate the irqs for VT-d Posted-Interrupts here.
> When 'pst' is set in IRTE, the associated irq will be posted to guests
> instead of interrupt remapping. The destination of the interrupt is
> set in Posted-Interrupts Descriptor, and the migration happens during
> vCPU scheduling.
>
> However, we still update the cached irte here, which can be used when
> changing back to remapping mode.
>
> Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
> Reviewed-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> ---
> drivers/iommu/intel_irq_remapping.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
> diff --git a/drivers/iommu/intel_irq_remapping.c
> b/drivers/iommu/intel_irq_remapping.c index 48c2051..ab9057a 100644 ---
> a/drivers/iommu/intel_irq_remapping.c +++
> b/drivers/iommu/intel_irq_remapping.c @@ -977,6 +977,7 @@
> intel_ir_set_affinity(struct irq_data *data, const struct cpumask *mask,
> {
> struct intel_ir_data *ir_data = data->chip_data; struct irte *irte =
> &ir_data->irte_entry; + struct irte_pi *irte_pi = (struct irte_pi
> *)irte; struct irq_cfg *cfg = irqd_cfg(data); struct irq_data *parent
> = data->parent_data; int ret;
> @@ -991,7 +992,10 @@ intel_ir_set_affinity(struct irq_data *data,
> const struct cpumask *mask,
> */
> irte->vector = cfg->vector;
> irte->dest_id = IRTE_DEST(cfg->dest_apicid);
> - modify_irte(&ir_data->irq_2_iommu, irte);
> +
> + /* We don't need to modify irte if the interrupt is for posting. */
> + if (irte_pi->pst != 1)
> + modify_irte(&ir_data->irq_2_iommu, irte);
What happens if user changes the IRQ affinity manually?
>
> /*
> * After this point, all the interrupts will start arriving
Best regards,
Yang
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