2 files changed, 18 insertions, 15 deletions

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index e15cdcd8cb3c..a4ddeade8ac4 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -182,6 +182,7 @@ config INTEL_IOMMU
         select IOMMU_IOVA
         select NEED_DMA_MAP_STATE
         select DMAR_TABLE
+        select SWIOTLB
         help
           DMA remapping (DMAR) devices support enables independent address
           translations for Direct Memory Access (DMA) from devices.
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index ce6baabc9dcc..0af7b4669264 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4547,22 +4547,20 @@ const struct attribute_group *intel_iommu_groups[] = {
         NULL,
 };
 
-static int __init platform_optin_force_iommu(void)
+static inline bool has_untrusted_dev(void)
 {
         struct pci_dev *pdev = NULL;
-        bool has_untrusted_dev = false;
 
-        if (!dmar_platform_optin() || no_platform_optin)
-                return 0;
+        for_each_pci_dev(pdev)
+                if (pdev->untrusted)
+                        return true;
 
-        for_each_pci_dev(pdev) {
-                if (pdev->untrusted) {
-                        has_untrusted_dev = true;
-                        break;
-                }
-        }
+        return false;
+}
 
-        if (!has_untrusted_dev)
+static int __init platform_optin_force_iommu(void)
+{
+        if (!dmar_platform_optin() || no_platform_optin || !has_untrusted_dev())
                 return 0;
 
         if (no_iommu || dmar_disabled)
@@ -4576,9 +4574,6 @@ static int __init platform_optin_force_iommu(void)
                 iommu_identity_mapping |= IDENTMAP_ALL;
 
         dmar_disabled = 0;
-#if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)
-        swiotlb = 0;
-#endif
         no_iommu = 0;
 
         return 1;
@@ -4718,7 +4713,14 @@ int __init intel_iommu_init(void)
         up_write(&dmar_global_lock);
 
 #if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB)
-        swiotlb = 0;
+        /*
+         * If the system has no untrusted device or the user has decided
+         * to disable the bounce page mechanisms, we don't need swiotlb.
+         * Mark this and the pre-allocated bounce pages will be released
+         * later.
+         */
+        if (!has_untrusted_dev() || intel_no_bounce)
+                swiotlb = 0;
 #endif
         dma_ops = &intel_dma_ops;