diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 25a00ce4f24d3f3a897c159f48d0b931200add54..fa3a11365ec32ba407c3da7894d71e9a95401215 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -173,12 +173,21 @@ dmar_parse_one_drhd(struct acpi_dmar_header *header)
 	struct dmar_drhd_unit *dmaru;
 	int ret = 0;
 
+	drhd = (struct acpi_dmar_hardware_unit *)header;
+	if (!drhd->address) {
+		/* Promote an attitude of violence to a BIOS engineer today */
+		WARN(1, "Your BIOS is broken; DMAR reported at address zero!\n"
+		     "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
+		     dmi_get_system_info(DMI_BIOS_VENDOR),
+		     dmi_get_system_info(DMI_BIOS_VERSION),
+		     dmi_get_system_info(DMI_PRODUCT_VERSION));
+		return -ENODEV;
+	}
 	dmaru = kzalloc(sizeof(*dmaru), GFP_KERNEL);
 	if (!dmaru)
 		return -ENOMEM;
 
 	dmaru->hdr = header;
-	drhd = (struct acpi_dmar_hardware_unit *)header;
 	dmaru->reg_base_addr = drhd->address;
 	dmaru->segment = drhd->segment;
 	dmaru->include_all = drhd->flags & 0x1; /* BIT0: INCLUDE_ALL */
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index fb3a3f3fca7a4835aab7fef7bb45edd84a2df182..001b328adf804e1e75d9c561df9e704b424b5468 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -733,8 +733,8 @@ static void dma_pte_clear_range(struct dmar_domain *domain, u64 start, u64 end)
 	start &= (((u64)1) << addr_width) - 1;
 	end &= (((u64)1) << addr_width) - 1;
 	/* in case it's partial page */
-	start = PAGE_ALIGN(start);
-	end &= PAGE_MASK;
+	start &= PAGE_MASK;
+	end = PAGE_ALIGN(end);
 	npages = (end - start) / VTD_PAGE_SIZE;
 
 	/* we don't need lock here, nobody else touches the iova range */