Messages in this thread Patch in this message | | | Date | Mon, 8 Jun 2015 06:44:32 -0700 | From | tip-bot for Feng Wu <> | Subject | [tip:x86/apic] iommu, x86: Avoid migrating VT-d posted interrupts |
| |
Commit-ID: ad2453cb74dd0e1ba201b449b610557dc7434234 Gitweb: http://git.kernel.org/tip/ad2453cb74dd0e1ba201b449b610557dc7434234 Author: Feng Wu <feng.wu@intel.com> AuthorDate: Fri, 5 Jun 2015 13:42:50 +0800 Committer: Thomas Gleixner <tglx@linutronix.de> 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@intel.com> Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com> 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/1433482974-14614-6-git-send-email-feng.wu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- 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
| |