diff --git a/arch/x86/include/asm/amd_iommu.h b/arch/x86/include/asm/amd_iommu.h
index bdf96f119f06..ac95995b7bad 100644
--- a/arch/x86/include/asm/amd_iommu.h
+++ b/arch/x86/include/asm/amd_iommu.h
@@ -25,6 +25,7 @@
 #ifdef CONFIG_AMD_IOMMU
 extern int amd_iommu_init(void);
 extern int amd_iommu_init_dma_ops(void);
+extern int amd_iommu_init_passthrough(void);
 extern void amd_iommu_detect(void);
 extern irqreturn_t amd_iommu_int_handler(int irq, void *data);
 extern void amd_iommu_flush_all_domains(void);
diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index 3a6a3259e1eb..86a56b49f2c6 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -143,6 +143,7 @@
 #define EVT_BUFFER_SIZE		8192 /* 512 entries */
 #define EVT_LEN_MASK		(0x9ULL << 56)
 
+#define PAGE_MODE_NONE    0x00
 #define PAGE_MODE_1_LEVEL 0x01
 #define PAGE_MODE_2_LEVEL 0x02
 #define PAGE_MODE_3_LEVEL 0x03
@@ -194,6 +195,9 @@
 #define PD_DMA_OPS_MASK		(1UL << 0) /* domain used for dma_ops */
 #define PD_DEFAULT_MASK		(1UL << 1) /* domain is a default dma_ops
 					      domain for an IOMMU */
+#define PD_PASSTHROUGH_MASK	(1UL << 2) /* domain has no page
+					      translation */
+
 extern bool amd_iommu_dump;
 #define DUMP_printk(format, arg...)					\
 	do {								\
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 8c93b7c7735e..dc19ed43b54e 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -41,6 +41,13 @@ static DEFINE_RWLOCK(amd_iommu_devtable_lock);
 static LIST_HEAD(iommu_pd_list);
 static DEFINE_SPINLOCK(iommu_pd_list_lock);
 
+/*
+ * Domain for untranslated devices - only allocated
+ * if iommu=pt passed on kernel cmd line.
+ */
+static struct protection_domain *pt_domain;
+
+#ifdef CONFIG_IOMMU_API
 static struct iommu_ops amd_iommu_ops;
 
 /*
@@ -1130,32 +1137,48 @@ static struct protection_domain *domain_for_device(u16 devid)
  * If a device is not yet associated with a domain, this function does
  * assigns it visible for the hardware
  */
-static void attach_device(struct amd_iommu *iommu,
-			  struct protection_domain *domain,
-			  u16 devid)
+static void __attach_device(struct amd_iommu *iommu,
+			    struct protection_domain *domain,
+			    u16 devid)
 {
-	unsigned long flags;
-	u64 pte_root = virt_to_phys(domain->pt_root);
+	u64 pte_root;
 
-	domain->dev_cnt += 1;
+	/* lock domain */
+	spin_lock(&domain->lock);
+
+	pte_root = virt_to_phys(domain->pt_root);
 
 	pte_root |= (domain->mode & DEV_ENTRY_MODE_MASK)
 		    << DEV_ENTRY_MODE_SHIFT;
 	pte_root |= IOMMU_PTE_IR | IOMMU_PTE_IW | IOMMU_PTE_P | IOMMU_PTE_TV;
 
-	write_lock_irqsave(&amd_iommu_devtable_lock, flags);
-	amd_iommu_dev_table[devid].data[0] = lower_32_bits(pte_root);
-	amd_iommu_dev_table[devid].data[1] = upper_32_bits(pte_root);
 	amd_iommu_dev_table[devid].data[2] = domain->id;
+	amd_iommu_dev_table[devid].data[1] = upper_32_bits(pte_root);
+	amd_iommu_dev_table[devid].data[0] = lower_32_bits(pte_root);
 
 	amd_iommu_pd_table[devid] = domain;
+
+	domain->dev_cnt += 1;
+
+	/* ready */
+	spin_unlock(&domain->lock);
+}
+
+static void attach_device(struct amd_iommu *iommu,
+			  struct protection_domain *domain,
+			  u16 devid)
+{
+	unsigned long flags;
+
+	write_lock_irqsave(&amd_iommu_devtable_lock, flags);
+	__attach_device(iommu, domain, devid);
 	write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 
-       /*
-        * We might boot into a crash-kernel here. The crashed kernel
-        * left the caches in the IOMMU dirty. So we have to flush
-        * here to evict all dirty stuff.
-        */
+	/*
+	 * We might boot into a crash-kernel here. The crashed kernel
+	 * left the caches in the IOMMU dirty. So we have to flush
+	 * here to evict all dirty stuff.
+	 */
 	iommu_queue_inv_dev_entry(iommu, devid);
 	iommu_flush_tlb_pde(iommu, domain->id);
 }
@@ -1182,6 +1205,15 @@ static void __detach_device(struct protection_domain *domain, u16 devid)
 
 	/* ready */
 	spin_unlock(&domain->lock);
+
+	/*
+	 * If we run in passthrough mode the device must be assigned to the
+	 * passthrough domain if it is detached from any other domain
+	 */
+	if (iommu_pass_through) {
+		struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
+		__attach_device(iommu, pt_domain, devid);
+	}
 }
 
 /*
@@ -1227,6 +1259,8 @@ static int device_change_notifier(struct notifier_block *nb,
 	case BUS_NOTIFY_UNBOUND_DRIVER:
 		if (!domain)
 			goto out;
+		if (iommu_pass_through)
+			break;
 		detach_device(domain, devid);
 		break;
 	case BUS_NOTIFY_ADD_DEVICE:
@@ -2051,19 +2085,47 @@ static void cleanup_domain(struct protection_domain *domain)
 	write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 }
 
-static int amd_iommu_domain_init(struct iommu_domain *dom)
+static void protection_domain_free(struct protection_domain *domain)
+{
+	if (!domain)
+		return;
+
+	if (domain->id)
+		domain_id_free(domain->id);
+
+	kfree(domain);
+}
+
+static struct protection_domain *protection_domain_alloc(void)
 {
 	struct protection_domain *domain;
 
 	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
 	if (!domain)
-		return -ENOMEM;
+		return NULL;
 
 	spin_lock_init(&domain->lock);
-	domain->mode = PAGE_MODE_3_LEVEL;
 	domain->id = domain_id_alloc();
 	if (!domain->id)
+		goto out_err;
+
+	return domain;
+
+out_err:
+	kfree(domain);
+
+	return NULL;
+}
+
+static int amd_iommu_domain_init(struct iommu_domain *dom)
+{
+	struct protection_domain *domain;
+
+	domain = protection_domain_alloc();
+	if (!domain)
 		goto out_free;
+
+	domain->mode    = PAGE_MODE_3_LEVEL;
 	domain->pt_root = (void *)get_zeroed_page(GFP_KERNEL);
 	if (!domain->pt_root)
 		goto out_free;
@@ -2073,7 +2135,7 @@ static int amd_iommu_domain_init(struct iommu_domain *dom)
 	return 0;
 
 out_free:
-	kfree(domain);
+	protection_domain_free(domain);
 
 	return -ENOMEM;
 }
@@ -2254,3 +2316,46 @@ static struct iommu_ops amd_iommu_ops = {
 	.domain_has_cap = amd_iommu_domain_has_cap,
 };
 
+/*****************************************************************************
+ *
+ * The next functions do a basic initialization of IOMMU for pass through
+ * mode
+ *
+ * In passthrough mode the IOMMU is initialized and enabled but not used for
+ * DMA-API translation.
+ *
+ *****************************************************************************/
+
+int __init amd_iommu_init_passthrough(void)
+{
+	struct pci_dev *dev = NULL;
+	u16 devid, devid2;
+
+	/* allocate passthroug domain */
+	pt_domain = protection_domain_alloc();
+	if (!pt_domain)
+		return -ENOMEM;
+
+	pt_domain->mode |= PAGE_MODE_NONE;
+
+	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+		struct amd_iommu *iommu;
+
+		devid = calc_devid(dev->bus->number, dev->devfn);
+		if (devid > amd_iommu_last_bdf)
+			continue;
+
+		devid2 = amd_iommu_alias_table[devid];
+
+		iommu = amd_iommu_rlookup_table[devid2];
+		if (!iommu)
+			continue;
+
+		__attach_device(iommu, pt_domain, devid);
+		__attach_device(iommu, pt_domain, devid2);
+	}
+
+	pr_info("AMD-Vi: Initialized for Passthrough Mode\n");
+
+	return 0;
+}
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 779ace292475..b4b61d462dcc 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -1252,12 +1252,18 @@ int __init amd_iommu_init(void)
 	if (ret)
 		goto free;
 
-	ret = amd_iommu_init_dma_ops();
+	if (iommu_pass_through)
+		ret = amd_iommu_init_passthrough();
+	else
+		ret = amd_iommu_init_dma_ops();
 	if (ret)
 		goto free;
 
 	enable_iommus();
 
+	if (iommu_pass_through)
+		goto out;
+
 	printk(KERN_INFO "AMD-Vi: device isolation ");
 	if (amd_iommu_isolate)
 		printk("enabled\n");
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 1a041bcf506b..873aa079d166 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -32,7 +32,14 @@ int no_iommu __read_mostly;
 /* Set this to 1 if there is a HW IOMMU in the system */
 int iommu_detected __read_mostly = 0;
 
-int iommu_pass_through;
+/*
+ * This variable becomes 1 if iommu=pt is passed on the kernel command line.
+ * If this variable is 1, IOMMU implementations do no DMA ranslation for
+ * devices and allow every device to access to whole physical memory. This is
+ * useful if a user want to use an IOMMU only for KVM device assignment to
+ * guests and not for driver dma translation.
+ */
+int iommu_pass_through __read_mostly;
 
 dma_addr_t bad_dma_address __read_mostly = 0;
 EXPORT_SYMBOL(bad_dma_address);