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authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>2009-11-10 19:46:20 +0900
committerIngo Molnar <mingo@elte.hu>2009-11-10 12:32:07 +0100
commit75f1cdf1dda92cae037ec848ae63690d91913eac (patch)
tree9c12705002ebfa2d75333c20a19d0ac15f1db1d9 /arch/x86/kernel
parentad32e8cb86e7894aac51c8963eaa9f36bb8a4e14 (diff)
x86: Handle HW IOMMU initialization failure gracefully
If HW IOMMU initialization fails (Intel VT-d often does this, typically due to BIOS bugs), we fall back to nommu. It doesn't work for the majority since nowadays we have more than 4GB memory so we must use swiotlb instead of nommu. The problem is that it's too late to initialize swiotlb when HW IOMMU initialization fails. We need to allocate swiotlb memory earlier from bootmem allocator. Chris explained the issue in detail: http://marc.info/?l=linux-kernel&m=125657444317079&w=2 The current x86 IOMMU initialization sequence is too complicated and handling the above issue makes it more hacky. This patch changes x86 IOMMU initialization sequence to handle the above issue cleanly. The new x86 IOMMU initialization sequence are: 1. we initialize the swiotlb (and setting swiotlb to 1) in the case of (max_pfn > MAX_DMA32_PFN && !no_iommu). dma_ops is set to swiotlb_dma_ops or nommu_dma_ops. if swiotlb usage is forced by the boot option, we finish here. 2. we call the detection functions of all the IOMMUs 3. the detection function sets x86_init.iommu.iommu_init to the IOMMU initialization function (so we can avoid calling the initialization functions of all the IOMMUs needlessly). 4. if the IOMMU initialization function doesn't need to swiotlb then sets swiotlb to zero (e.g. the initialization is sucessful). 5. if we find that swiotlb is set to zero, we free swiotlb resource. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: chrisw@sous-sol.org Cc: dwmw2@infradead.org Cc: joerg.roedel@amd.com Cc: muli@il.ibm.com LKML-Reference: <1257849980-22640-10-git-send-email-fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/amd_iommu.c2
-rw-r--r--arch/x86/kernel/amd_iommu_init.c2
-rw-r--r--arch/x86/kernel/aperture_64.c2
-rw-r--r--arch/x86/kernel/pci-calgary_64.c10
-rw-r--r--arch/x86/kernel/pci-dma.c21
-rw-r--r--arch/x86/kernel/pci-gart_64.c1
-rw-r--r--arch/x86/kernel/pci-nommu.c9
-rw-r--r--arch/x86/kernel/pci-swiotlb.c7
8 files changed, 21 insertions, 33 deletions
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 0285521e0a9..66237fde758 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 c41aabddaa2..0d4581e602a 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 (swiotlb || no_iommu || (iommu_detected && !gart_iommu_aperture))
+ if (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 03933cf0b63..e0dfb6856aa 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 (swiotlb && !valid_agp) {
+ } else if (!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 47bd419ea4d..833f491440b 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 (swiotlb || no_iommu || iommu_detected)
+ if (no_iommu || iommu_detected)
return;
if (!use_calgary)
@@ -1445,10 +1445,6 @@ 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;
@@ -1476,11 +1472,7 @@ 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 bed05e2e589..a234e63c265 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -124,24 +124,24 @@ 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();
#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,
@@ -291,10 +291,15 @@ static int __init pci_iommu_init(void)
#ifdef CONFIG_PCI
dma_debug_add_bus(&pci_bus_type);
#endif
-
x86_init.iommu.iommu_init();
- no_iommu_init();
+ if (swiotlb) {
+ printk(KERN_INFO "PCI-DMA: "
+ "Using software bounce buffering for IO (SWIOTLB)\n");
+ swiotlb_print_info();
+ } else
+ swiotlb_free();
+
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 0410bd30060..919182e15d1 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -833,6 +833,7 @@ 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 a3933d4330c..875e3822ae6 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -103,12 +103,3 @@ 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 ea20ef7ca52..17ce4221bd0 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -46,13 +46,12 @@ void __init pci_swiotlb_init(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
#ifdef CONFIG_X86_64
- if ((!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN))
+ if (!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;
}