iommu: Set default domain type at runtime

Set the default domain-type at runtime, not at compile-time.
This keeps default domain type setting in one place when we
have to change it at runtime.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/iommu.c

@@ -26,11 +26,8 @@
 
 static struct kset *iommu_group_kset;
 static DEFINE_IDA(iommu_group_ida);
-#ifdef CONFIG_IOMMU_DEFAULT_PASSTHROUGH
-static unsigned int iommu_def_domain_type = IOMMU_DOMAIN_IDENTITY;
-#else
-static unsigned int iommu_def_domain_type = IOMMU_DOMAIN_DMA;
-#endif
+
+static unsigned int iommu_def_domain_type __read_mostly;
 static bool iommu_dma_strict __read_mostly = true;
 static u32 iommu_cmd_line __read_mostly;
 
@@ -76,7 +73,7 @@ static void iommu_set_cmd_line_dma_api(void)
 	iommu_cmd_line |= IOMMU_CMD_LINE_DMA_API;
 }
 
-static bool __maybe_unused iommu_cmd_line_dma_api(void)
+static bool iommu_cmd_line_dma_api(void)
 {
 	return !!(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API);
 }
@@ -115,8 +112,18 @@ static const char *iommu_domain_type_str(unsigned int t)
 
 static int __init iommu_subsys_init(void)
 {
-	pr_info("Default domain type: %s\n",
-		iommu_domain_type_str(iommu_def_domain_type));
+	bool cmd_line = iommu_cmd_line_dma_api();
+
+	if (!cmd_line) {
+		if (IS_ENABLED(CONFIG_IOMMU_DEFAULT_PASSTHROUGH))
+			iommu_set_default_passthrough(false);
+		else
+			iommu_set_default_translated(false);
+	}
+
+	pr_info("Default domain type: %s %s\n",
+		iommu_domain_type_str(iommu_def_domain_type),
+		cmd_line ? "(set via kernel command line)" : "");
 
 	return 0;
 }