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iommu, x86: Avoid migrating VT-d posted interrupts

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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>
This commit is contained in:
Feng Wu 2015-06-09 13:20:33 +08:00 committed by Thomas Gleixner
parent 2705a3d2a6
commit d75f152fc3
1 changed files with 4 additions and 1 deletions
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5
drivers/iommu/intel_irq_remapping.c
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@ -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