2 files changed, 5 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/pci-swiotlb.c b/arch/x86_64/kernel/pci-swiotlb.c
index ebdb77fe2057..6a55f87ba97f 100644
--- a/arch/x86_64/kernel/pci-swiotlb.c
+++ b/arch/x86_64/kernel/pci-swiotlb.c
@@ -31,9 +31,10 @@ struct dma_mapping_ops swiotlb_dma_ops = {
 void pci_swiotlb_init(void)
 {
         /* don't initialize swiotlb if iommu=off (no_iommu=1) */
-        if (!iommu_detected && !no_iommu &&
-            (end_pfn > MAX_DMA32_PFN || force_iommu))
+        if (!iommu_detected && !no_iommu && end_pfn > MAX_DMA32_PFN)
                swiotlb = 1;
+        if (swiotlb_force)
+                swiotlb = 1;
         if (swiotlb) {
                 printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
                 swiotlb_init();
diff --git a/include/asm-x86_64/swiotlb.h b/include/asm-x86_64/swiotlb.h
index 5f9a01805821..ba94ab3d2673 100644
--- a/include/asm-x86_64/swiotlb.h
+++ b/include/asm-x86_64/swiotlb.h
@@ -42,6 +42,8 @@ extern void swiotlb_free_coherent (struct device *hwdev, size_t size,
 extern int swiotlb_dma_supported(struct device *hwdev, u64 mask);
 extern void swiotlb_init(void);
 
+extern int swiotlb_force;
+
 #ifdef CONFIG_SWIOTLB
 extern int swiotlb;
 #else