[PATCH 1/2] iommu/amd: Don't use 512GB pages

[PATCH 1/2] iommu/amd: Don't use 512GB pages

[Joerg Roedel]

There is a bug in the hardware that will be triggered when
this page size is used. Make sure this does not happen.

Signed-off-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 drivers/iommu/amd_iommu.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index cb63cc5..98d74ab 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -66,8 +66,10 @@
  *
  * If at some point we'd like to utilize the IOMMU core's new behavior,
  * we could change this to advertise the real page sizes we support.
+ *
+ * 512GB Pages are not supported due to a hardware bug
  */
-#define AMD_IOMMU_PGSIZES	(~0xFFFUL)
+#define AMD_IOMMU_PGSIZES	((~0xFFFUL) & ~(2ULL << 38))
 
 static DEFINE_RWLOCK(amd_iommu_devtable_lock);
 
-- 
1.7.9.5

[PATCH 2/2] iommu/amd: Remove obsolete comment

[Joerg Roedel]

The AMD IOMMU driver only uses the page-sizes it gets from
IOMMU core and uses the appropriate page-size. So this
comment is not necessary.

Signed-off-by: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
---
 drivers/iommu/amd_iommu.c |   10 ----------
 1 file changed, 10 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 98d74ab..c1c74e0 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -57,16 +57,6 @@
  * physically contiguous memory regions it is mapping into page sizes
  * that we support.
  *
- * Traditionally the IOMMU core just handed us the mappings directly,
- * after making sure the size is an order of a 4KiB page and that the
- * mapping has natural alignment.
- *
- * To retain this behavior, we currently advertise that we support
- * all page sizes that are an order of 4KiB.
- *
- * If at some point we'd like to utilize the IOMMU core's new behavior,
- * we could change this to advertise the real page sizes we support.
- *
  * 512GB Pages are not supported due to a hardware bug
  */
 #define AMD_IOMMU_PGSIZES	((~0xFFFUL) & ~(2ULL << 38))
-- 
1.7.9.5