diff -r f91555fa60d4 xen/arch/x86/hvm/svm/amd_iommu/amd-iommu-map.c
--- a/xen/arch/x86/hvm/svm/amd_iommu/amd-iommu-map.c	Fri Nov 30 15:10:01 2007 +0100
+++ b/xen/arch/x86/hvm/svm/amd_iommu/amd-iommu-map.c	Fri Nov 30 15:18:10 2007 +0100
@@ -468,3 +468,23 @@ int amd_iommu_unmap_page(struct domain *
         return -ENOMEM;
     }
 }
+
+void amd_iommu_unmap_all_domain_pages(struct domain *d)
+{
+    unsigned long flags;
+    u64 io_addr;
+    int domain_id;
+    struct amd_iommu *iommu;
+    struct hvm_iommu *hd = domain_hvm_iommu(d);
+
+    domain_id = hd->domain_id;
+    io_addr = 0x7FFFFFFFFFFF;  /* flush entire cache*/
+
+    for_each_amd_iommu(iommu)
+    {
+        spin_lock_irqsave(&iommu->lock, flags);
+        invalidate_iommu_page(iommu, io_addr, domain_id);
+        flush_command_buffer(iommu);
+        spin_unlock_irqrestore(&iommu->lock, flags);
+    }
+}
diff -r f91555fa60d4 xen/arch/x86/hvm/svm/amd_iommu/pci-amd-iommu.c
--- a/xen/arch/x86/hvm/svm/amd_iommu/pci-amd-iommu.c	Fri Nov 30 15:10:01 2007 +0100
+++ b/xen/arch/x86/hvm/svm/amd_iommu/pci-amd-iommu.c	Fri Nov 30 15:18:10 2007 +0100
@@ -499,3 +499,199 @@ error_out:
     deallocate_domain_resources(hd);
     return -ENOMEM;
 }
+
+static void amd_iommu_disable_device_entry(
+    struct domain *domain, struct amd_iommu *iommu, int requestor_id)
+{
+    void *dte;
+    unsigned long flags;
+
+    dte = iommu->dev_table.buffer +
+        (requestor_id * IOMMU_DEV_TABLE_ENTRY_SIZE);
+
+    if ( amd_iommu_is_dte_page_translation_valid((u32 *)dte) )
+    {
+        spin_lock_irqsave(&iommu->lock, flags); 
+        memset (dte, 0, IOMMU_DEV_TABLE_ENTRY_SIZE);
+        invalidate_dev_table_entry(iommu, requestor_id);
+        flush_command_buffer(iommu);
+        IOV_DPRINTK(XENLOG_INFO IOVPREFIX, "disable DTE 0x%x,"
+            " domain_id:%d, paging_mode:%d\n",
+            requestor_id,  domain_hvm_iommu(domain)->domain_id,
+            domain_hvm_iommu(domain)->paging_mode);
+        spin_unlock_irqrestore(&iommu->lock, flags);
+    }
+}
+
+static int reassign_device( struct domain *source, struct domain *target,
+    u8 bus, u8 devfn)
+{
+    struct hvm_iommu *source_hd = domain_hvm_iommu(source);
+    struct hvm_iommu *target_hd = domain_hvm_iommu(target);
+    struct pci_dev *pdev;
+    struct amd_iommu *iommu;
+    int req_id, bdf;
+    unsigned long flags;
+
+    for_each_pdev( source, pdev )
+    {
+        if ( (pdev->bus != bus) || (pdev->devfn != devfn) )
+            continue;
+
+        pdev->bus = bus;
+        pdev->devfn = devfn;
+
+        bdf = (bus << 8) | pdev->devfn;
+        req_id = requestor_id_from_bdf(bdf);
+        iommu = find_iommu_for_device(bus, devfn);
+
+        /* Move pci device from the source domain to target domain. */
+        spin_lock_irqsave(&source_hd->iommu_list_lock, flags);
+        spin_lock_irqsave(&target_hd->iommu_list_lock, flags);
+        list_move(&pdev->list, &target_hd->pdev_list);
+        spin_unlock_irqrestore(&target_hd->iommu_list_lock, flags);
+        spin_unlock_irqrestore(&source_hd->iommu_list_lock, flags);
+
+        if ( iommu )
+        {
+            amd_iommu_disable_device_entry(source, iommu, req_id);
+            amd_iommu_setup_domain_device(target, iommu, req_id);
+            IOV_GDPRINTK(XENLOG_INFO IOVPREFIX,
+                "reassign %x:%x.%x: domain %d -> domain %d\n",
+                bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+                source->domain_id, target->domain_id);
+        }
+        else
+        {
+            IOV_GDPRINTK(XENLOG_ERR IOVPREFIX, "failed to find iommu."
+                " %x:%x.%x cannot be accessed by domain %d\n", 
+                bus, PCI_SLOT(devfn), PCI_FUNC(devfn), target->domain_id);
+            return -ENODEV;
+        }
+
+        break;
+    }
+    return 0;
+}
+
+int amd_iommu_assign_device(struct domain *d, u8 bus, u8 devfn)
+{
+    struct hvm_iommu *hd;
+    int ret;
+
+    hd = domain_hvm_iommu(d);
+    ret = reassign_device(dom0, d, bus, devfn);
+
+    return ret;
+}
+
+static void release_domain_devices(struct domain *d)
+{
+    struct hvm_iommu *hd  = domain_hvm_iommu(d);
+    struct pci_dev *pdev;
+
+    while ( !list_empty(&hd->pdev_list) )
+    {
+        pdev = list_entry(hd->pdev_list.next, typeof(*pdev), list);
+        IOV_GDPRINTK(XENLOG_INFO IOVPREFIX,
+                "release devices: %x:%x.%x\n",
+                pdev->bus, PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
+        reassign_device(d, dom0, pdev->bus, pdev->devfn);
+    }
+}
+
+static void deallocate_next_page_table(void *table, unsigned long index,
+            int level)
+{
+    unsigned long next_index;
+    void *next_table, *pde;
+    int next_level;
+
+    pde = table + (index * IOMMU_PAGE_TABLE_ENTRY_SIZE);
+    next_table = amd_iommu_get_vptr_from_page_table_entry((u32 *)pde);
+
+    if (next_table) 
+    {
+        next_level = level - 1;
+        if (next_level > 1)
+        {
+            next_index = 0;
+            do {
+                deallocate_next_page_table(next_table,
+                    next_index, next_level);
+                ++next_index;
+            } while (next_index < PTE_PER_TABLE_SIZE);
+        }
+
+        free_xenheap_page(next_table);
+    }
+}
+
+static void deallocate_domain_page_tables(struct domain *d)
+{
+    unsigned long index;
+    struct hvm_iommu *hd  = domain_hvm_iommu(d);
+
+    if (hd ->root_table)
+    {
+        index = 0;
+        do {
+            deallocate_next_page_table(hd->root_table,
+                index, hd->paging_mode);
+            ++index;
+        } while (index < PTE_PER_TABLE_SIZE);
+
+        free_xenheap_page(hd ->root_table);
+    }
+
+    hd ->root_table = NULL;
+}
+
+void amd_iommu_domain_destroy(struct domain *d)
+{
+    struct hvm_irq_dpci *hvm_irq_dpci = d->arch.hvm_domain.irq.dpci;
+    uint32_t i;
+    struct hvm_iommu *hd  = domain_hvm_iommu(d);
+    struct list_head *ioport_list, *digl_list, *tmp;
+    struct g2m_ioport *ioport;
+    struct dev_intx_gsi_link *digl;
+
+    if ( !amd_iommu_enabled )
+        return;
+
+    if ( hvm_irq_dpci != NULL )
+    {
+        for ( i = 0; i < NR_IRQS; i++ )
+            if ( hvm_irq_dpci->mirq[i].valid )
+            {
+                pirq_guest_unbind(d, i);
+                kill_timer(&hvm_irq_dpci->hvm_timer[irq_to_vector(i)]);
+
+                list_for_each_safe ( digl_list, tmp,
+                                     &hvm_irq_dpci->mirq[i].digl_list )
+                {
+                    digl = list_entry(digl_list,
+                                      struct dev_intx_gsi_link, list);
+                    list_del(&digl->list);
+                    xfree(digl);
+                }
+            }
+
+        d->arch.hvm_domain.irq.dpci = NULL;
+        xfree(hvm_irq_dpci);
+    }
+
+    if ( hd )
+    {
+        list_for_each_safe ( ioport_list, tmp, &hd->g2m_ioport_list )
+        {
+            ioport = list_entry(ioport_list, struct g2m_ioport, list);
+            list_del(&ioport->list);
+            xfree(ioport);
+        }
+    }
+
+    amd_iommu_unmap_all_domain_pages(d);
+    deallocate_domain_page_tables(d);
+    release_domain_devices(d);
+}
diff -r f91555fa60d4 xen/include/asm-x86/amd-iommu.h
--- a/xen/include/asm-x86/amd-iommu.h	Fri Nov 30 15:10:01 2007 +0100
+++ b/xen/include/asm-x86/amd-iommu.h	Fri Nov 30 15:18:10 2007 +0100
@@ -33,6 +33,8 @@ extern struct list_head amd_iommu_head;
 
 extern int __init amd_iommu_detect(void);
 extern int amd_iommu_domain_init(struct domain *domain);
+extern int amd_iommu_assign_device(struct domain *d, u8 bus, u8 devfn);
+extern void amd_iommu_domain_destroy(struct domain *d);
 extern int amd_iommu_map_page(struct domain *d, unsigned long gfn,
         unsigned long mfn);
 extern int amd_iommu_unmap_page(struct domain *d, unsigned long gfn);
diff -r f91555fa60d4 xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
--- a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h	Fri Nov 30 15:10:01 2007 +0100
+++ b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h	Fri Nov 30 15:18:10 2007 +0100
@@ -63,6 +63,7 @@ void __init enable_iommu(struct amd_iomm
 void __init enable_iommu(struct amd_iommu *iommu);
 
 /* mapping functions */
+void amd_iommu_unmap_all_domain_pages(struct domain *d);
 void *amd_iommu_get_vptr_from_page_table_entry(u32 *entry);
 
 /* device table functions */