1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 5f164ff3026e..f5a662a50acb 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -491,6 +491,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
         int map_size;
         u32 ver;
         static int iommu_allocated = 0;
+        int agaw;
 
         iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
         if (!iommu)
@@ -506,6 +507,15 @@ int alloc_iommu(struct dmar_drhd_unit *drhd)
         iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG);
         iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG);
 
+        agaw = iommu_calculate_agaw(iommu);
+        if (agaw < 0) {
+                printk(KERN_ERR
+                        "Cannot get a valid agaw for iommu (seq_id = %d)\n",
+                        iommu->seq_id);
+                goto error;
+        }
+        iommu->agaw = agaw;
+
         /* the registers might be more than one page */
         map_size = max_t(int, ecap_max_iotlb_offset(iommu->ecap),
                 cap_max_fault_reg_offset(iommu->cap));