1 files changed, 19 insertions, 0 deletions

diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index e8c52a1eec06..ccc4a7fb97a3 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -405,6 +405,25 @@ config IOMMU
           device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
           too.
 
+config CALGARY_IOMMU
+        bool "IBM Calgary IOMMU support"
+        default y
+        select SWIOTLB
+        depends on PCI && EXPERIMENTAL
+        help
+          Support for hardware IOMMUs in IBM's xSeries x366 and x460
+          systems. Needed to run systems with more than 3GB of memory
+          properly with 32-bit PCI devices that do not support DAC
+          (Double Address Cycle). Calgary also supports bus level
+          isolation, where all DMAs pass through the IOMMU.  This
+          prevents them from going anywhere except their intended
+          destination. This catches hard-to-find kernel bugs and
+          mis-behaving drivers and devices that do not use the DMA-API
+          properly to set up their DMA buffers.  The IOMMU can be
+          turned off at boot time with the iommu=off parameter.
+          Normally the kernel will make the right choice by itself.
+          If unsure, say Y.
+
 # need this always selected by IOMMU for the VIA workaround
 config SWIOTLB
         bool