diff -r 71d6d6f2ecd6 xen/drivers/passthrough/amd/iommu_map.c
--- a/xen/drivers/passthrough/amd/iommu_map.c	Fri Aug 07 09:54:43 2009 +0100
+++ b/xen/drivers/passthrough/amd/iommu_map.c	Tue Aug 18 16:05:00 2009 +0200
@@ -256,7 +256,7 @@ static void amd_iommu_set_page_directory
 
 void amd_iommu_set_dev_table_entry(u32 *dte, u64 root_ptr, u64 intremap_ptr,
                                    u16 domain_id, u8 sys_mgt, u8 dev_ex,
-                                   u8 paging_mode)
+                                   u8 paging_mode, u8 valid, u8 int_valid)
 {
     u64 addr_hi, addr_lo;
     u32 entry;
@@ -297,7 +297,8 @@ void amd_iommu_set_dev_table_entry(u32 *
     set_field_in_reg_u32(0xB, entry,
                          IOMMU_DEV_TABLE_INT_TABLE_LENGTH_MASK,
                          IOMMU_DEV_TABLE_INT_TABLE_LENGTH_SHIFT, &entry);
-    set_field_in_reg_u32(IOMMU_CONTROL_ENABLED, entry,
+    set_field_in_reg_u32(int_valid ? IOMMU_CONTROL_ENABLED :
+                         IOMMU_CONTROL_DISABLED, entry,
                          IOMMU_DEV_TABLE_INT_VALID_MASK,
                          IOMMU_DEV_TABLE_INT_VALID_SHIFT, &entry);
     set_field_in_reg_u32(IOMMU_CONTROL_ENABLED, entry,
@@ -340,7 +341,8 @@ void amd_iommu_set_dev_table_entry(u32 *
     set_field_in_reg_u32(IOMMU_CONTROL_ENABLED, entry,
                          IOMMU_DEV_TABLE_TRANSLATION_VALID_MASK,
                          IOMMU_DEV_TABLE_TRANSLATION_VALID_SHIFT, &entry);
-    set_field_in_reg_u32(IOMMU_CONTROL_ENABLED, entry,
+    set_field_in_reg_u32(valid ? IOMMU_CONTROL_ENABLED :
+                         IOMMU_CONTROL_DISABLED, entry,
                          IOMMU_DEV_TABLE_VALID_MASK,
                          IOMMU_DEV_TABLE_VALID_SHIFT, &entry);
     dte[0] = entry;
diff -r 71d6d6f2ecd6 xen/drivers/passthrough/amd/pci_amd_iommu.c
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c	Fri Aug 07 09:54:43 2009 +0100
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c	Tue Aug 18 16:05:00 2009 +0200
@@ -69,7 +69,7 @@ static void amd_iommu_setup_domain_devic
     void *dte;
     unsigned long flags;
     int req_id;
-    u8 sys_mgt, dev_ex;
+    u8 sys_mgt, dev_ex, valid = 1, int_valid = 1;
     struct hvm_iommu *hd = domain_hvm_iommu(domain);
 
     BUG_ON( !hd->root_table || !hd->paging_mode || !int_remap_table );
@@ -85,12 +85,17 @@ static void amd_iommu_setup_domain_devic
         /* bind DTE to domain page-tables */
         sys_mgt = ivrs_mappings[req_id].dte_sys_mgt_enable;
         dev_ex = ivrs_mappings[req_id].dte_allow_exclusion;
+
+        if ( iommu_passthrough && (domain->domain_id == 0) )
+            valid = 0;
+        if ( !iommu_intremap )
+            int_valid = 0;
 
         amd_iommu_set_dev_table_entry((u32 *)dte,
                                       page_to_maddr(hd->root_table),
                                       virt_to_maddr(int_remap_table),
                                       hd->domain_id, sys_mgt, dev_ex,
-                                      hd->paging_mode);
+                                      hd->paging_mode, valid, int_valid);
 
         invalidate_dev_table_entry(iommu, req_id);
         invalidate_interrupt_table(iommu, req_id);
@@ -223,9 +228,13 @@ static int amd_iommu_domain_init(struct 
     if ( domain->domain_id == 0 )
     {
         unsigned long i; 
-       /* setup 1:1 page table for dom0 */
-        for ( i = 0; i < max_page; i++ )
-            amd_iommu_map_page(domain, i, i);
+
+        if ( !iommu_passthrough )
+        {
+            /* setup 1:1 page table for dom0 */
+            for ( i = 0; i < max_page; i++ )
+                amd_iommu_map_page(domain, i, i);
+        }
 
         amd_iommu_setup_dom0_devices(domain);
     }
diff -r 71d6d6f2ecd6 xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
--- a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h	Fri Aug 07 09:54:43 2009 +0100
+++ b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h	Tue Aug 18 16:05:00 2009 +0200
@@ -68,7 +68,8 @@ void invalidate_all_iommu_pages(struct d
 
 /* device table functions */
 void amd_iommu_set_dev_table_entry(u32 *dte, u64 root_ptr, u64 intremap_ptr,
-        u16 domain_id, u8 sys_mgt, u8 dev_ex, u8 paging_mode);
+        u16 domain_id, u8 sys_mgt, u8 dev_ex, u8 paging_mode,
+        u8 valid, u8 int_valid);
 int amd_iommu_is_dte_page_translation_valid(u32 *entry);
 void invalidate_dev_table_entry(struct amd_iommu *iommu, u16 devic_id);