diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 568c52317757..1b65302e07b1 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -71,6 +71,8 @@
 #define IVHD_FLAG_ISOC_EN_MASK          0x08
 
 #define IVMD_FLAG_EXCL_RANGE            0x08
+#define IVMD_FLAG_IW                    0x04
+#define IVMD_FLAG_IR                    0x02
 #define IVMD_FLAG_UNITY_MAP             0x01
 
 #define ACPI_DEVFLAG_INITPASS           0x01
@@ -1121,16 +1123,14 @@ static void __init set_device_exclusion_range(u16 devid, struct ivmd_header *m)
 	if (!(m->flags & IVMD_FLAG_EXCL_RANGE))
 		return;
 
-	if (iommu) {
-		/*
-		 * We only can configure exclusion ranges per IOMMU, not
-		 * per device. But we can enable the exclusion range per
-		 * device. This is done here
-		 */
-		set_dev_entry_bit(devid, DEV_ENTRY_EX);
-		iommu->exclusion_start = m->range_start;
-		iommu->exclusion_length = m->range_length;
-	}
+	/*
+	 * Treat per-device exclusion ranges as r/w unity-mapped regions
+	 * since some buggy BIOSes might lead to the overwritten exclusion
+	 * range (exclusion_start and exclusion_length members). This
+	 * happens when there are multiple exclusion ranges (IVMD entries)
+	 * defined in ACPI table.
+	 */
+	m->flags = (IVMD_FLAG_IW | IVMD_FLAG_IR | IVMD_FLAG_UNITY_MAP);
 }
 
 /*