x86/amd-iommu: Fix crash when request_mem_region fails

When request_mem_region fails the error path tries to
disable the IOMMUs. This accesses the mmio-region which was
not allocated leading to a kernel crash. This patch fixes
the issue.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 3bacb4d0844c..1405346c62b4 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,