diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index e68b148..b332b7f 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -231,6 +231,7 @@
  * independent of their use.
  */
 struct protection_domain {
+	struct list_head list;  /* for list of all protection domains */
 	spinlock_t lock;	/* mostly used to lock the page table*/
 	u16 id;			/* the domain id written to the device table */
 	int mode;		/* paging mode (0-6 levels) */
@@ -376,6 +377,12 @@
 extern int amd_iommus_present;
 
 /*
+ * Declarations for the global list of all protection domains
+ */
+extern spinlock_t amd_iommu_pd_lock;
+extern struct list_head amd_iommu_pd_list;
+
+/*
  * Structure defining one entry in the device table
  */
 struct dev_table_entry {