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>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e07c432c731ff9a516fe8b23228af0fe6fa1d29a..fc8f93606ec1a1d7efd4f85fefd5b2474660e318 100644 (file)
--- 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>