diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index c5d78c87248a..49a669b1ce11 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -440,7 +440,14 @@ static int iommu_init_device(struct device *dev)
 
 	dev_data->alias = get_alias(dev);
 
-	if (dev_is_pci(dev) && pci_iommuv2_capable(to_pci_dev(dev))) {
+	/*
+	 * By default we use passthrough mode for IOMMUv2 capable device.
+	 * But if amd_iommu=force_isolation is set (e.g. to debug DMA to
+	 * invalid address), we ignore the capability for the device so
+	 * it'll be forced to go into translation mode.
+	 */
+	if ((iommu_pass_through || !amd_iommu_force_isolation) &&
+	    dev_is_pci(dev) && pci_iommuv2_capable(to_pci_dev(dev))) {
 		struct amd_iommu *iommu;
 
 		iommu = amd_iommu_rlookup_table[dev_data->devid];