1 files changed, 37 insertions, 7 deletions

diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index a5bc528d4328..8f972cbddef0 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -10,7 +10,8 @@
 #include <asm/iommu.h>
 #include <asm/swiotlb.h>
 #include <asm/dma.h>
-
+#include <asm/xen/swiotlb-xen.h>
+#include <asm/iommu_table.h>
 int swiotlb __read_mostly;
 
 static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
@@ -41,25 +42,42 @@ static struct dma_map_ops swiotlb_dma_ops = {
 };
 
 /*
- * pci_swiotlb_detect - set swiotlb to 1 if necessary
+ * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
  *
  * This returns non-zero if we are forced to use swiotlb (by the boot
  * option).
  */
-int __init pci_swiotlb_detect(void)
+int __init pci_swiotlb_detect_override(void)
 {
         int use_swiotlb = swiotlb | swiotlb_force;
 
+        if (swiotlb_force)
+                swiotlb = 1;
+
+        return use_swiotlb;
+}
+IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
+                  pci_xen_swiotlb_detect,
+                  pci_swiotlb_init,
+                  pci_swiotlb_late_init);
+
+/*
+ * if 4GB or more detected (and iommu=off not set) return 1
+ * and set swiotlb to 1.
+ */
+int __init pci_swiotlb_detect_4gb(void)
+{
         /* don't initialize swiotlb if iommu=off (no_iommu=1) */
 #ifdef CONFIG_X86_64
         if (!no_iommu && max_pfn > MAX_DMA32_PFN)
                 swiotlb = 1;
 #endif
-        if (swiotlb_force)
-                swiotlb = 1;
-
-        return use_swiotlb;
+        return swiotlb;
 }
+IOMMU_INIT(pci_swiotlb_detect_4gb,
+           pci_swiotlb_detect_override,
+           pci_swiotlb_init,
+           pci_swiotlb_late_init);
 
 void __init pci_swiotlb_init(void)
 {
@@ -68,3 +86,15 @@ void __init pci_swiotlb_init(void)
                 dma_ops = &swiotlb_dma_ops;
         }
 }
+
+void __init pci_swiotlb_late_init(void)
+{
+        /* An IOMMU turned us off. */
+        if (!swiotlb)
+                swiotlb_free();
+        else {
+                printk(KERN_INFO "PCI-DMA: "
+                       "Using software bounce buffering for IO (SWIOTLB)\n");
+                swiotlb_print_info();
+        }
+}