Messages in this thread Patch in this message | | | From | Feng Wu <> | Subject | [v4 4/8] iommu, x86: No need to migrating irq for VT-d Posted-Interrupts | Date | Mon, 2 Feb 2015 16:01:50 +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 | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-)
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); /* * After this point, all the interrupts will start arriving -- 1.7.1
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