diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 7b287cb38b7a..0cbc5fd26c3c 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -33,6 +33,7 @@
 #include <linux/timer.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
+#include <asm/tboot.h>
 
 #undef PREFIX
 #define PREFIX "DMAR:"
@@ -413,6 +414,12 @@ parse_dmar_table(void)
 	 */
 	dmar_table_detect();
 
+	/*
+	 * ACPI tables may not be DMA protected by tboot, so use DMAR copy
+	 * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
+	 */
+	dmar_tbl = tboot_get_dmar_table(dmar_tbl);
+
 	dmar = (struct acpi_table_dmar *)dmar_tbl;
 	if (!dmar)
 		return -ENODEV;
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index ebc9b8dca881..2dc72a6d7412 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -38,6 +38,7 @@
 #include <linux/intel-iommu.h>
 #include <linux/sysdev.h>
 #include <asm/cacheflush.h>
+#include <asm/tboot.h>
 #include <asm/iommu.h>
 #include "pci.h"
 
@@ -3183,12 +3184,22 @@ static int __init init_iommu_sysfs(void)
 int __init intel_iommu_init(void)
 {
 	int ret = 0;
+	int force_on = 0;
 
-	if (dmar_table_init())
-		return 	-ENODEV;
+	/* VT-d is required for a TXT/tboot launch, so enforce that */
+	force_on = tboot_force_iommu();
 
-	if (dmar_dev_scope_init())
+	if (dmar_table_init()) {
+		if (force_on)
+			panic("tboot: Failed to initialize DMAR table\n");
 		return 	-ENODEV;
+	}
+
+	if (dmar_dev_scope_init()) {
+		if (force_on)
+			panic("tboot: Failed to initialize DMAR device scope\n");
+		return 	-ENODEV;
+	}
 
 	/*
 	 * Check the need for DMA-remapping initialization now.
@@ -3204,6 +3215,8 @@ int __init intel_iommu_init(void)
 
 	ret = init_dmars();
 	if (ret) {
+		if (force_on)
+			panic("tboot: Failed to initialize DMARs\n");
 		printk(KERN_ERR "IOMMU: dmar init failed\n");
 		put_iova_domain(&reserved_iova_list);
 		iommu_exit_mempool();