[PATCH v9 3/7] s390/pci: add support for IOMMU default DMA mode build options

[Zhen Lei]

The default DMA mode is LAZY on s390, this patch make it can be set to
STRICT at build time. It can be overridden by boot option.

There is no functional change.

Signed-off-by: Zhen Lei <thunder.leizhen at huawei.com>
Acked-by: Sebastian Ott <sebott at linux.ibm.com>
---
 arch/s390/pci/pci_dma.c | 2 +-
 drivers/iommu/Kconfig   | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 9e52d1527f71495..784ad1e0acecfb1 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -17,7 +17,7 @@
 
 static struct kmem_cache *dma_region_table_cache;
 static struct kmem_cache *dma_page_table_cache;
-static int s390_iommu_strict;
+static int s390_iommu_strict = IS_ENABLED(CONFIG_IOMMU_DEFAULT_STRICT);
 
 static int zpci_refresh_global(struct zpci_dev *zdev)
 {
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index fe715fb295c6ed2..a8dd69d175fb3c6 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -78,6 +78,7 @@ config IOMMU_DEBUGFS
 choice
 	prompt "IOMMU default DMA mode"
 	depends on IOMMU_API
+	default IOMMU_DEFAULT_LAZY if S390_IOMMU
 	default IOMMU_DEFAULT_STRICT
 	help
 	  This option allows an IOMMU DMA mode to be chosen at build time, to
@@ -89,6 +90,7 @@ choice
 
 config IOMMU_DEFAULT_PASSTHROUGH
 	bool "passthrough"
+	depends on !S390_IOMMU
 	help
 	  In this mode, the DMA access through IOMMU without any addresses
 	  translation. That means, the wrong or illegal DMA access can not
-- 
1.8.3