1 files changed, 17 insertions, 3 deletions

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 3bacb4d0844c..3cc63e2b8dd4 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -287,8 +287,12 @@ static u8 * __init iommu_map_mmio_space(u64 address)
 {
         u8 *ret;
 
-        if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu"))
+        if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu")) {
+                pr_err("AMD-Vi: Can not reserve memory region %llx for mmio\n",
+                        address);
+                pr_err("AMD-Vi: This is a BIOS bug. Please contact your hardware vendor\n");
                 return NULL;
+        }
 
         ret = ioremap_nocache(address, MMIO_REGION_LENGTH);
         if (ret != NULL)
@@ -1314,7 +1318,7 @@ static int __init amd_iommu_init(void)
                 ret = amd_iommu_init_dma_ops();
 
         if (ret)
-                goto free;
+                goto free_disable;
 
         amd_iommu_init_api();
 
@@ -1332,9 +1336,10 @@ static int __init amd_iommu_init(void)
 out:
         return ret;
 
-free:
+free_disable:
         disable_iommus();
 
+free:
         amd_iommu_uninit_devices();
 
         free_pages((unsigned long)amd_iommu_pd_alloc_bitmap,
@@ -1353,6 +1358,15 @@ free:
 
         free_unity_maps();
 
+#ifdef CONFIG_GART_IOMMU
+        /*
+         * We failed to initialize the AMD IOMMU - try fallback to GART
+         * if possible.
+         */
+        gart_iommu_init();
+
+#endif
+
         goto out;
 }