Messages in this thread Patch in this message |  | | From | Feng Wu <> | Subject | [v9 5/9] iommu, x86: No need to migrating irq for VT-d Posted-Interrupts | Date | Fri, 5 Jun 2015 13:42:50 +0800 |
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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@intel.com> Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> --- drivers/iommu/intel_irq_remapping.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c index 028d628..c30845a 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -1002,7 +1002,10 @@ 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); + + /* Update the hardware only if the interrupt is in remapped mode. */ + if (ir_data->irq_2_iommu.mode == IRQ_REMAPPING) + modify_irte(&ir_data->irq_2_iommu, irte); /* * After this point, all the interrupts will start arriving -- 2.1.0
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