1 files changed, 26 insertions, 7 deletions

diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 56883fc1c7be..beeaef84e151 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -613,6 +613,8 @@ int __init dmar_table_init(void)
         return 0;
 }
 
+static int bios_warned;
+
 int __init check_zero_address(void)
 {
         struct acpi_table_dmar *dmar;
@@ -643,6 +645,7 @@ int __init check_zero_address(void)
                                      dmi_get_system_info(DMI_BIOS_VENDOR),
                                      dmi_get_system_info(DMI_BIOS_VERSION),
                                      dmi_get_system_info(DMI_PRODUCT_VERSION));
+                                bios_warned = 1;
                                 goto failed;
                         }
 
@@ -662,6 +665,7 @@ int __init check_zero_address(void)
                                       dmi_get_system_info(DMI_BIOS_VENDOR),
                                       dmi_get_system_info(DMI_BIOS_VERSION),
                                       dmi_get_system_info(DMI_PRODUCT_VERSION));
+                                bios_warned = 1;
                                 goto failed;
                         }
                 }
@@ -722,6 +726,18 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
         int agaw = 0;
         int msagaw = 0;
 
+        if (!drhd->reg_base_addr) {
+                if (!bios_warned) {
+                        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));
+                        bios_warned = 1;
+                }
+                return -EINVAL;
+        }
+
         iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
         if (!iommu)
                 return -ENOMEM;
@@ -738,13 +754,16 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
         iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
 
         if (iommu->cap == (uint64_t)-1 && iommu->ecap == (uint64_t)-1) {
-                /* Promote an attitude of violence to a BIOS engineer today */
-                WARN(1, "Your BIOS is broken; DMAR reported at address %llx returns all ones!\n"
-                     "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
-                     drhd->reg_base_addr,
-                     dmi_get_system_info(DMI_BIOS_VENDOR),
-                     dmi_get_system_info(DMI_BIOS_VERSION),
-                     dmi_get_system_info(DMI_PRODUCT_VERSION));
+                if (!bios_warned) {
+                        /* Promote an attitude of violence to a BIOS engineer today */
+                        WARN(1, "Your BIOS is broken; DMAR reported at address %llx returns all ones!\n"
+                             "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
+                             drhd->reg_base_addr,
+                             dmi_get_system_info(DMI_BIOS_VENDOR),
+                             dmi_get_system_info(DMI_BIOS_VERSION),
+                             dmi_get_system_info(DMI_PRODUCT_VERSION));
+                        bios_warned = 1;
+                }
                 goto err_unmap;
         }