x86, AMD IOMMU: add documentation for kernel parameters

Add documentation for the kernel parameters introduced with this driver.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: iommu@lists.linux-foundation.org
Cc: bhavna.sarathy@amd.com
Cc: Sebastian.Biemueller@amd.com
Cc: robert.richter@amd.com
Cc: joro@8bytes.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 12 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e07c432c731f..fc8f93606ec1 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -271,6 +271,18 @@ and is between 256 and 4096 characters. It is defined in the file
         aic79xx=        [HW,SCSI]
                         See Documentation/scsi/aic79xx.txt.
 
+        amd_iommu=      [HW,X86-84]
+                        Pass parameters to the AMD IOMMU driver in the system.
+                        Possible values are:
+                        off     - disable the driver for AMD IOMMU
+                        isolate - enable device isolation (each device, as far
+                                  as possible, will get its own protection
+                                  domain)
+        amd_iommu_size= [HW,X86-64]
+                        Define the size of the aperture for the AMD IOMMU
+                        driver. Possible values are:
+                        '32M', '64M' (default), '128M', '256M', '512M', '1G'
+
         amijoy.map=     [HW,JOY] Amiga joystick support
                         Map of devices attached to JOY0DAT and JOY1DAT
                         Format: <a>,<b>