Commit-ID: ad2453cb74dd0e1ba201b449b610557dc7434234 Gitweb: http://git.kernel.org/tip/ad2453cb74dd0e1ba201b449b610557dc7434234 Author: Feng Wu <feng.wu@xxxxxxxxx> AuthorDate: Fri, 5 Jun 2015 13:42:50 +0800 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Mon, 8 Jun 2015 15:41:32 +0200 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. Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> Reviewed-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx> Acked-by: David Woodhouse <David.Woodhouse@xxxxxxxxx> Acked-by: Joerg Roedel <joro@xxxxxxxxxx> Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: dwmw2@xxxxxxxxxxxxx Link: http://lkml.kernel.org/r/1433482974-14614-6-git-send-email-feng.wu@xxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- 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 68bce0a..3bcb459 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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