Intel IOMMU Suspend/Resume Support - Interrupt Remapping

This patch enables suspend/resume for interrupt remapping. During suspend,
interrupt remapping is disabled. When resume, interrupt remapping is enabled
again.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 59 insertions, 2 deletions

diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index b041a409f4a7..c26633d7e7da 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -470,7 +470,7 @@ static int setup_intr_remapping(struct intel_iommu *iommu, int mode)
 /*
  * Disable Interrupt Remapping.
  */
-static void disable_intr_remapping(struct intel_iommu *iommu)
+static void iommu_disable_intr_remapping(struct intel_iommu *iommu)
 {
         unsigned long flags;
         u32 sts;
@@ -478,6 +478,12 @@ static void disable_intr_remapping(struct intel_iommu *iommu)
         if (!ecap_ir_support(iommu->ecap))
                 return;
 
+        /*
+         * global invalidation of interrupt entry cache before disabling
+         * interrupt-remapping.
+         */
+        qi_global_iec(iommu);
+
         spin_lock_irqsave(&iommu->register_lock, flags);
 
         sts = dmar_readq(iommu->reg + DMAR_GSTS_REG);
@@ -511,7 +517,7 @@ int __init enable_intr_remapping(int eim)
                  * Disable intr remapping and queued invalidation, if already
                  * enabled prior to OS handover.
                  */
-                disable_intr_remapping(iommu);
+                iommu_disable_intr_remapping(iommu);
 
                 dmar_disable_qi(iommu);
         }
@@ -639,3 +645,54 @@ int __init parse_ioapics_under_ir(void)
 
         return ir_supported;
 }
+
+void disable_intr_remapping(void)
+{
+        struct dmar_drhd_unit *drhd;
+        struct intel_iommu *iommu = NULL;
+
+        /*
+         * Disable Interrupt-remapping for all the DRHD's now.
+         */
+        for_each_iommu(iommu, drhd) {
+                if (!ecap_ir_support(iommu->ecap))
+                        continue;
+
+                iommu_disable_intr_remapping(iommu);
+        }
+}
+
+int reenable_intr_remapping(int eim)
+{
+        struct dmar_drhd_unit *drhd;
+        int setup = 0;
+        struct intel_iommu *iommu = NULL;
+
+        for_each_iommu(iommu, drhd)
+                if (iommu->qi)
+                        dmar_reenable_qi(iommu);
+
+        /*
+         * Setup Interrupt-remapping for all the DRHD's now.
+         */
+        for_each_iommu(iommu, drhd) {
+                if (!ecap_ir_support(iommu->ecap))
+                        continue;
+
+                /* Set up interrupt remapping for iommu.*/
+                iommu_set_intr_remapping(iommu, eim);
+                setup = 1;
+        }
+
+        if (!setup)
+                goto error;
+
+        return 0;
+
+error:
+        /*
+         * handle error condition gracefully here!
+         */
+        return -1;
+}
+