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>

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 3bacb4d0844c1e6b7794b6a23013dcbf77f3694e..1405346c62b4a183504bc342ab9cb3f90494cc3b 100644 (file)
--- 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,