diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index b041a40..c26633d 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -470,7 +470,7 @@
 /*
  * 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 @@
 	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 @@
 		 * 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 @@
 
 	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;
+}
+