iommu, x86: Save the mode (posted or remapped) of an IRTE

Add a new field to struct irq_2_iommu, which captures whether the
associated IRTE is in posted mode or remapped mode. We update this
field when the IRTE is written into the table.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Joerg Roedel <joro@8bytes.org>
Cc: jiang.liu@linux.intel.com
Cc: iommu@lists.linux-foundation.org
Cc: dwmw2@infradead.org
Link: http://lkml.kernel.org/r/1433827237-3382-6-git-send-email-feng.wu@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index a643eecf9d29..68bce0a52b9b 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -18,6 +18,11 @@
 
 #include "irq_remapping.h"
 
+enum irq_mode {
+        IRQ_REMAPPING,
+        IRQ_POSTING,
+};
+
 struct ioapic_scope {
         struct intel_iommu *iommu;
         unsigned int id;
@@ -37,6 +42,7 @@ struct irq_2_iommu {
         u16 irte_index;
         u16 sub_handle;
         u8  irte_mask;
+        enum irq_mode mode;
 };
 
 struct intel_ir_data {
@@ -104,6 +110,7 @@ static int alloc_irte(struct intel_iommu *iommu, int irq,
                 irq_iommu->irte_index =  index;
                 irq_iommu->sub_handle = 0;
                 irq_iommu->irte_mask = mask;
+                irq_iommu->mode = IRQ_REMAPPING;
         }
         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 
@@ -144,6 +151,9 @@ static int modify_irte(struct irq_2_iommu *irq_iommu,
         __iommu_flush_cache(iommu, irte, sizeof(*irte));
 
         rc = qi_flush_iec(iommu, index, 0);
+
+        /* Update iommu mode according to the IRTE mode */
+        irq_iommu->mode = irte->pst ? IRQ_POSTING : IRQ_REMAPPING;
         raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags);
 
         return rc;