This adds Kconfig option INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON
to make it easier for distributions to enable or disable the
Intel IOMMU scalable mode by default during kernel build.
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
---
drivers/iommu/Kconfig | 12 ++++++++++++
drivers/iommu/intel-iommu.c | 7 ++++++-
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 0b9d78a0f3ac..bcd1c9510458 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -248,6 +248,18 @@ config INTEL_IOMMU_FLOPPY_WA
workaround will setup a 1:1 mapping for the first
16MiB to make floppy (an ISA device) work.
+config INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON
+ bool "Enable Intel IOMMU scalable mode by default"
+ depends on INTEL_IOMMU
+ help
+ Selecting this option will enable by default the scalable mode if
+ hardware presents the capability. The scalable mode is defined in
+ VT-d 3.0. The scalable mode capability could be checked by reading
+ /sys/devices/virtual/iommu/dmar*/intel-iommu/ecap. If this option
+ is not selected, scalable mode support could also be enabled by
+ passing intel_iommu=sm_on to the kernel. If not sure, please use
+ the default value.
+
config IRQ_REMAP
bool "Support for Interrupt Remapping"
depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 42966611a192..26c40134817e 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -355,9 +355,14 @@ static phys_addr_t intel_iommu_iova_to_phys(struct
iommu_domain *domain,
int dmar_disabled = 0;
#else
int dmar_disabled = 1;
-#endif /*CONFIG_INTEL_IOMMU_DEFAULT_ON*/
+#endif /* CONFIG_INTEL_IOMMU_DEFAULT_ON */
+#ifdef INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON
+int intel_iommu_sm = 1;
+#else
int intel_iommu_sm;
+#endif /* INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON */
+
int intel_iommu_enabled = 0;
EXPORT_SYMBOL_GPL(intel_iommu_enabled);
--
2.17.1
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