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authorFeng Wu <feng.wu@intel.com>2015-06-09 08:20:33 +0300
committerThomas Gleixner <tglx@linutronix.de>2015-06-12 12:33:52 +0300
commitd75f152fc389cdd73a6c17f1247fce9052fd579c (patch)
tree39cef2c68ba8080bc2a5f462003d0a6e9c570771
parent2705a3d2a690c3dd9f58c7d788bc0f432acdeceb (diff)
downloadlinux-d75f152fc389cdd73a6c17f1247fce9052fd579c.tar.xz
iommu, x86: Avoid migrating VT-d posted interrupts
When the interrupt is configured in posted mode, the destination of the interrupt is set in the Posted-Interrupts Descriptor and the migration of these interrupts happens during vCPU scheduling. We still update the cached irte, which will be used when changing back to remapping mode, but we avoid writing the table entry as this would overwrite the posted mode entry. Signed-off-by: Feng Wu <feng.wu@intel.com> Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Acked-by: Joerg Roedel <joro@8bytes.org> Cc: iommu@lists.linux-foundation.org Cc: dwmw2@infradead.org Link: http://lkml.kernel.org/r/1433827237-3382-7-git-send-email-feng.wu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--drivers/iommu/intel_irq_remapping.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 68bce0a52b9b..3bcb459905c4 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1003,7 +1003,10 @@ 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