AMD IOMMU: enable device isolation per default

commit 3ce1f93c6d53c3f91c3846cf66b018276c8ac2e7 upstream.

Impact: makes device isolation the default for AMD IOMMU

Some device drivers showed double-free bugs of DMA memory while testing
them with AMD IOMMU. If all devices share the same protection domain
this can lead to data corruption and data loss. Prevent this by putting
each device into its own protection domain per default.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1150444a21ab64140f13e706797f16664e28244f..792be8687b52ad0c9cf92ab0743ad01a01b51313 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -283,7 +283,7 @@ and is between 256 and 4096 characters. It is defined in the file
                        Possible values are:
                        isolate - enable device isolation (each device, as far
                                  as possible, will get its own protection
-                                 domain)
+                                 domain) [default]
        amd_iommu_size= [HW,X86-64]
                        Define the size of the aperture for the AMD IOMMU
                        driver. Possible values are:

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index bccd0ef359ab37a1044496f5ba89197c15418f66..a1378c4a79a1aeb598e6e5c24b84d9ae683aab72 100644 (file)
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -120,7 +120,7 @@ u16 amd_iommu_last_bdf;                     /* largest PCI device id we have
 LIST_HEAD(amd_iommu_unity_map);                /* a list of required unity mappings
                                           we find in ACPI */
 unsigned amd_iommu_aperture_order = 26; /* size of aperture in power of 2 */
-int amd_iommu_isolate;                 /* if 1, device isolation is enabled */
+int amd_iommu_isolate = 1;             /* if 1, device isolation is enabled */
 
 LIST_HEAD(amd_iommu_list);             /* list of all AMD IOMMUs in the
                                           system */