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-rw-r--r--arch/x86_64/Kconfig19
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
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