Revert "x86: Handle HW IOMMU initialization failure gracefully"

This reverts commit 75f1cdf1dda92cae037ec848ae63690d91913eac.

12 files changed, 39 insertions, 29 deletions

diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index df42a712361f..878b30715766 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -2,6 +2,7 @@
 #define _ASM_X86_IOMMU_H
 
 static inline void iommu_shutdown_noop(void) {}
+extern void no_iommu_init(void);
 extern struct dma_map_ops nommu_dma_ops;
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 66237fde758f..0285521e0a99 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2110,8 +2110,8 @@ int __init amd_iommu_init_dma_ops(void)
 		prealloc_protection_domains();
 
 	iommu_detected = 1;
+	force_iommu = 1;
 	bad_dma_address = 0;
-	swiotlb = 0;
 #ifdef CONFIG_GART_IOMMU
 	gart_iommu_aperture_disabled = 1;
 	gart_iommu_aperture = 0;
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 0d4581e602a4..c41aabddaa2a 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -1330,7 +1330,7 @@ static int __init early_amd_iommu_detect(struct acpi_table_header *table)
 
 void __init amd_iommu_detect(void)
 {
-	if (no_iommu || (iommu_detected && !gart_iommu_aperture))
+	if (swiotlb || no_iommu || (iommu_detected && !gart_iommu_aperture))
 		return;
 
 	if (acpi_table_parse("IVRS", early_amd_iommu_detect) == 0) {
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index e0dfb6856aa2..03933cf0b63c 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -458,7 +458,7 @@ out:
 
 	if (aper_alloc) {
 		/* Got the aperture from the AGP bridge */
-	} else if (!valid_agp) {
+	} else if (swiotlb && !valid_agp) {
 		/* Do nothing */
 	} else if ((!no_iommu && max_pfn > MAX_DMA32_PFN) ||
 		   force_iommu ||
diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 833f491440b9..47bd419ea4d2 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -1360,7 +1360,7 @@ void __init detect_calgary(void)
 	 * if the user specified iommu=off or iommu=soft or we found
 	 * another HW IOMMU already, bail out.
 	 */
-	if (no_iommu || iommu_detected)
+	if (swiotlb || no_iommu || iommu_detected)
 		return;
 
 	if (!use_calgary)
@@ -1445,6 +1445,10 @@ void __init detect_calgary(void)
 		printk(KERN_INFO "PCI-DMA: Calgary TCE table spec is %d\n",
 		       specified_table_size);
 
+		/* swiotlb for devices that aren't behind the Calgary. */
+		if (max_pfn > MAX_DMA32_PFN)
+			swiotlb = 1;
+
 		x86_init.iommu.iommu_init = calgary_iommu_init;
 	}
 	return;
@@ -1472,7 +1476,11 @@ int __init calgary_iommu_init(void)
 		return ret;
 	}
 
+	force_iommu = 1;
 	bad_dma_address = 0x0;
+	/* dma_ops is set to swiotlb or nommu */
+	if (!dma_ops)
+		dma_ops = &nommu_dma_ops;
 
 	return 0;
 }
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 835f09af77cf..5bd31553d2f2 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -123,26 +123,26 @@ static void __init dma32_free_bootmem(void)
 
 void __init pci_iommu_alloc(void)
 {
-	/* swiotlb is forced by the boot option */
-	int use_swiotlb = swiotlb;
 #ifdef CONFIG_X86_64
 	/* free the range so iommu could get some range less than 4G */
 	dma32_free_bootmem();
 #else
 	dma_ops = &nommu_dma_ops;
 #endif
-	pci_swiotlb_init();
-	if (use_swiotlb)
-		return;
 
+	/*
+	 * The order of these functions is important for
+	 * fall-back/fail-over reasons
+	 */
 	gart_iommu_hole_init();
 
 	detect_calgary();
 
 	detect_intel_iommu();
 
-	/* needs to be called after gart_iommu_hole_init */
 	amd_iommu_detect();
+
+	pci_swiotlb_init();
 }
 
 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
@@ -292,15 +292,10 @@ static int __init pci_iommu_init(void)
 #ifdef CONFIG_PCI
 	dma_debug_add_bus(&pci_bus_type);
 #endif
-	x86_init.iommu.iommu_init();
 
-	if (swiotlb) {
-		printk(KERN_INFO "PCI-DMA: "
-		       "Using software bounce buffering for IO (SWIOTLB)\n");
-		swiotlb_print_info();
-	} else
-		swiotlb_free();
+	x86_init.iommu.iommu_init();
 
+	no_iommu_init();
 	return 0;
 }
 /* Must execute after PCI subsystem */
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index 919182e15d1e..0410bd30060d 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -833,7 +833,6 @@ int __init gart_iommu_init(void)
 	flush_gart();
 	dma_ops = &gart_dma_ops;
 	x86_platform.iommu_shutdown = gart_iommu_shutdown;
-	swiotlb = 0;
 
 	return 0;
 }
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index 875e3822ae61..a3933d4330cd 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -103,3 +103,12 @@ struct dma_map_ops nommu_dma_ops = {
 	.sync_sg_for_device	= nommu_sync_sg_for_device,
 	.is_phys		= 1,
 };
+
+void __init no_iommu_init(void)
+{
+	if (dma_ops)
+		return;
+
+	force_iommu = 0; /* no HW IOMMU */
+	dma_ops = &nommu_dma_ops;
+}
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index 17ce4221bd03..ea20ef7ca523 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -46,12 +46,13 @@ void __init pci_swiotlb_init(void)
 {
 	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
 #ifdef CONFIG_X86_64
-	if (!no_iommu && max_pfn > MAX_DMA32_PFN)
+	if ((!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN))
 		swiotlb = 1;
 #endif
+	if (swiotlb_force)
+		swiotlb = 1;
 	if (swiotlb) {
 		swiotlb_init(0);
 		dma_ops = &swiotlb_dma_ops;
-	} else
-		dma_ops = &nommu_dma_ops;
+	}
 }
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index bab8c6e1ee6f..09598c8feb4d 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -644,7 +644,8 @@ void __init detect_intel_iommu(void)
 			       "x2apic and Intr-remapping.\n");
 #endif
 #ifdef CONFIG_DMAR
-		if (ret && !no_iommu && !iommu_detected && !dmar_disabled)
+		if (ret && !no_iommu && !iommu_detected && !swiotlb &&
+		    !dmar_disabled)
 			iommu_detected = 1;
 #endif
 #ifdef CONFIG_X86
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 34c8bbe6f9ec..c83113646223 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -3240,7 +3240,7 @@ int __init intel_iommu_init(void)
 	 * Check the need for DMA-remapping initialization now.
 	 * Above initialization will also be used by Interrupt-remapping.
 	 */
-	if (no_iommu || dmar_disabled)
+	if (no_iommu || swiotlb || dmar_disabled)
 		return -ENODEV;
 
 	iommu_init_mempool();
@@ -3261,9 +3261,7 @@ int __init intel_iommu_init(void)
 	"PCI-DMA: Intel(R) Virtualization Technology for Directed I/O\n");
 
 	init_timer(&unmap_timer);
-#ifdef CONFIG_SWIOTLB
-	swiotlb = 0;
-#endif
+	force_iommu = 1;
 	dma_ops = &intel_dma_ops;
 
 	init_iommu_sysfs();
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index e6755a0574fb..0c12d7cce300 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -109,10 +109,8 @@ setup_io_tlb_npages(char *str)
 	}
 	if (*str == ',')
 		++str;
-	if (!strcmp(str, "force")) {
+	if (!strcmp(str, "force"))
 		swiotlb_force = 1;
-		swiotlb = 1;
-	}
 	return 1;
 }
 __setup("swiotlb=", setup_io_tlb_npages);