[Qemu-devel] [PATCH qemu v9 1/2] memory/iommu: QOM'fy IOMMU MemoryRegion

[Alexey Kardashevskiy <aik@ozlabs.ru>]

This defines new QOM object - IOMMUMemoryRegion - with MemoryRegion
as a parent.

This moves IOMMU-related fields from MR to IOMMU MR. However to avoid
dymanic QOM casting in fast path (address_space_translate, etc),
this adds an @is_iommu boolean flag to MR and provides new helper to
do simple cast to IOMMU MR - memory_region_get_iommu. The flag
is set in the instance init callback. This defines
memory_region_is_iommu as memory_region_get_iommu()!=NULL.

This switches MemoryRegion to IOMMUMemoryRegion in most places except
the ones where MemoryRegion may be an alias.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
---
Changes:
v9:
* added rb:David

v8:
* moved is_iommu flag closer to the beginning of the MemoryRegion struct
* removed memory_region_init_iommu_type()

v7:
* rebased on top of the current upstream

v6:
* s/\<iommumr\>/iommu_mr/g

v5:
* fixed sparc64, first time in many years did run "./configure" without
--target-list :-D Sorry for the noise though :(

v4:
* fixed alpha, mips64el and sparc

v3:
* rebased on sha1 81b2d5ceb0

v2:
* added mr->is_iommu
* updated i386/x86_64/s390/sun
---
 hw/s390x/s390-pci-bus.h       |   2 +-
 include/exec/memory.h         |  55 ++++++++++++++--------
 include/hw/i386/intel_iommu.h |   2 +-
 include/hw/mips/mips.h        |   2 +-
 include/hw/ppc/spapr.h        |   3 +-
 include/hw/vfio/vfio-common.h |   2 +-
 include/qemu/typedefs.h       |   1 +
 exec.c                        |  12 ++---
 hw/alpha/typhoon.c            |   8 ++--
 hw/dma/rc4030.c               |   8 ++--
 hw/i386/amd_iommu.c           |   9 ++--
 hw/i386/intel_iommu.c         |  17 +++----
 hw/mips/mips_jazz.c           |   2 +-
 hw/pci-host/apb.c             |   6 +--
 hw/ppc/spapr_iommu.c          |  16 ++++---
 hw/s390x/s390-pci-bus.c       |   6 +--
 hw/s390x/s390-pci-inst.c      |   8 ++--
 hw/vfio/common.c              |  12 +++--
 hw/vfio/spapr.c               |   3 +-
 memory.c                      | 105 ++++++++++++++++++++++++++++--------------
 20 files changed, 170 insertions(+), 109 deletions(-)

diff --git a/hw/s390x/s390-pci-bus.h b/hw/s390x/s390-pci-bus.h
index cf142a3e68..6a599ed353 100644
--- a/hw/s390x/s390-pci-bus.h
+++ b/hw/s390x/s390-pci-bus.h
@@ -266,7 +266,7 @@ typedef struct S390PCIIOMMU {
     S390PCIBusDevice *pbdev;
     AddressSpace as;
     MemoryRegion mr;
-    MemoryRegion iommu_mr;
+    IOMMUMemoryRegion iommu_mr;
     bool enabled;
     uint64_t g_iota;
     uint64_t pba;
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 8503685455..92980abfad 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -35,6 +35,10 @@
 #define MEMORY_REGION(obj) \
         OBJECT_CHECK(MemoryRegion, (obj), TYPE_MEMORY_REGION)
 
+#define TYPE_IOMMU_MEMORY_REGION "qemu:iommu-memory-region"
+#define IOMMU_MEMORY_REGION(obj) \
+        OBJECT_CHECK(IOMMUMemoryRegion, (obj), TYPE_IOMMU_MEMORY_REGION)
+
 typedef struct MemoryRegionOps MemoryRegionOps;
 typedef struct MemoryRegionMmio MemoryRegionMmio;
 
@@ -198,16 +202,16 @@ struct MemoryRegionIOMMUOps {
      * set flag to IOMMU_NONE to mean that we don't need any
      * read/write permission checks, like, when for region replay.
      */
-    IOMMUTLBEntry (*translate)(MemoryRegion *iommu, hwaddr addr,
+    IOMMUTLBEntry (*translate)(IOMMUMemoryRegion *iommu, hwaddr addr,
                                IOMMUAccessFlags flag);
     /* Returns minimum supported page size */
-    uint64_t (*get_min_page_size)(MemoryRegion *iommu);
+    uint64_t (*get_min_page_size)(IOMMUMemoryRegion *iommu);
     /* Called when IOMMU Notifier flag changed */
-    void (*notify_flag_changed)(MemoryRegion *iommu,
+    void (*notify_flag_changed)(IOMMUMemoryRegion *iommu,
                                 IOMMUNotifierFlag old_flags,
                                 IOMMUNotifierFlag new_flags);
     /* Set this up to provide customized IOMMU replay function */
-    void (*replay)(MemoryRegion *iommu, IOMMUNotifier *notifier);
+    void (*replay)(IOMMUMemoryRegion *iommu, IOMMUNotifier *notifier);
 };
 
 typedef struct CoalescedMemoryRange CoalescedMemoryRange;
@@ -227,9 +231,9 @@ struct MemoryRegion {
     bool flush_coalesced_mmio;
     bool global_locking;
     uint8_t dirty_log_mask;
+    bool is_iommu;
     RAMBlock *ram_block;
     Object *owner;
-    const MemoryRegionIOMMUOps *iommu_ops;
 
     const MemoryRegionOps *ops;
     void *opaque;
@@ -252,6 +256,12 @@ struct MemoryRegion {
     const char *name;
     unsigned ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;
+};
+
+struct IOMMUMemoryRegion {
+    MemoryRegion parent_obj;
+
+    const MemoryRegionIOMMUOps *iommu_ops;
     QLIST_HEAD(, IOMMUNotifier) iommu_notify;
     IOMMUNotifierFlag iommu_notify_flags;
 };
@@ -618,13 +628,13 @@ static inline void memory_region_init_reservation(MemoryRegion *mr,
  * An IOMMU region translates addresses and forwards accesses to a target
  * memory region.
  *
- * @mr: the #MemoryRegion to be initialized
+ * @iommu_mr: the #IOMMUMemoryRegion to be initialized
  * @owner: the object that tracks the region's reference count
  * @ops: a function that translates addresses into the @target region
  * @name: used for debugging; not visible to the user or ABI
  * @size: size of the region.
  */
-void memory_region_init_iommu(MemoryRegion *mr,
+void memory_region_init_iommu(IOMMUMemoryRegion *iommu_mr,
                               struct Object *owner,
                               const MemoryRegionIOMMUOps *ops,
                               const char *name,
@@ -679,20 +689,25 @@ static inline bool memory_region_is_romd(MemoryRegion *mr)
 }
 
 /**
- * memory_region_is_iommu: check whether a memory region is an iommu
+ * memory_region_get_iommu: check whether a memory region is an iommu
  *
- * Returns %true is a memory region is an iommu.
+ * Returns pointer to IOMMUMemoryRegion if a memory region is an iommu,
+ * otherwise NULL.
  *
  * @mr: the memory region being queried
  */
-static inline bool memory_region_is_iommu(MemoryRegion *mr)
+static inline IOMMUMemoryRegion *memory_region_get_iommu(MemoryRegion *mr)
 {
     if (mr->alias) {
-        return memory_region_is_iommu(mr->alias);
+        return memory_region_get_iommu(mr->alias);
     }
-    return mr->iommu_ops;
+    if (mr->is_iommu) {
+        return (IOMMUMemoryRegion *) mr;
+    }
+    return NULL;
 }
 
+#define memory_region_is_iommu(mr) (memory_region_get_iommu(mr) != NULL)
 
 /**
  * memory_region_iommu_get_min_page_size: get minimum supported page size
@@ -700,9 +715,9 @@ static inline bool memory_region_is_iommu(MemoryRegion *mr)
  *
  * Returns minimum supported page size for an iommu.
  *
- * @mr: the memory region being queried
+ * @iommu_mr: the memory region being queried
  */
-uint64_t memory_region_iommu_get_min_page_size(MemoryRegion *mr);
+uint64_t memory_region_iommu_get_min_page_size(IOMMUMemoryRegion *iommu_mr);
 
 /**
  * memory_region_notify_iommu: notify a change in an IOMMU translation entry.
@@ -716,12 +731,12 @@ uint64_t memory_region_iommu_get_min_page_size(MemoryRegion *mr);
  * Note: for any IOMMU implementation, an in-place mapping change
  * should be notified with an UNMAP followed by a MAP.
  *
- * @mr: the memory region that was changed
+ * @iommu_mr: the memory region that was changed
  * @entry: the new entry in the IOMMU translation table.  The entry
  *         replaces all old entries for the same virtual I/O address range.
  *         Deleted entries have .@perm == 0.
  */
-void memory_region_notify_iommu(MemoryRegion *mr,
+void memory_region_notify_iommu(IOMMUMemoryRegion *iommu_mr,
                                 IOMMUTLBEntry entry);
 
 /**
@@ -756,18 +771,18 @@ void memory_region_register_iommu_notifier(MemoryRegion *mr,
  * a notifier with the minimum page granularity returned by
  * mr->iommu_ops->get_page_size().
  *
- * @mr: the memory region to observe
+ * @iommu_mr: the memory region to observe
  * @n: the notifier to which to replay iommu mappings
  */
-void memory_region_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n);
+void memory_region_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n);
 
 /**
  * memory_region_iommu_replay_all: replay existing IOMMU translations
  * to all the notifiers registered.
  *
- * @mr: the memory region to observe
+ * @iommu_mr: the memory region to observe
  */
-void memory_region_iommu_replay_all(MemoryRegion *mr);
+void memory_region_iommu_replay_all(IOMMUMemoryRegion *iommu_mr);
 
 /**
  * memory_region_unregister_iommu_notifier: unregister a notifier for
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 3e51876b75..45fba4ff97 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -83,7 +83,7 @@ struct VTDAddressSpace {
     PCIBus *bus;
     uint8_t devfn;
     AddressSpace as;
-    MemoryRegion iommu;
+    IOMMUMemoryRegion iommu;
     MemoryRegion root;
     MemoryRegion sys_alias;
     MemoryRegion iommu_ir;      /* Interrupt region: 0xfeeXXXXX */
diff --git a/include/hw/mips/mips.h b/include/hw/mips/mips.h
index 16412dc150..2f6774d540 100644
--- a/include/hw/mips/mips.h
+++ b/include/hw/mips/mips.h
@@ -19,6 +19,6 @@ typedef struct rc4030DMAState *rc4030_dma;
 void rc4030_dma_read(void *dma, uint8_t *buf, int len);
 void rc4030_dma_write(void *dma, uint8_t *buf, int len);
 
-DeviceState *rc4030_init(rc4030_dma **dmas, MemoryRegion **dma_mr);
+DeviceState *rc4030_init(rc4030_dma **dmas, IOMMUMemoryRegion **dma_mr);
 
 #endif
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index a66bbac352..a3dfe7b90b 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -595,7 +595,8 @@ struct sPAPRTCETable {
     bool bypass;
     bool need_vfio;
     int fd;
-    MemoryRegion root, iommu;
+    MemoryRegion root;
+    IOMMUMemoryRegion iommu;
     struct VIOsPAPRDevice *vdev; /* for @bypass migration compatibility only */
     QLIST_ENTRY(sPAPRTCETable) list;
 };
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 9521013d52..d67779729c 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -95,7 +95,7 @@ typedef struct VFIOContainer {
 
 typedef struct VFIOGuestIOMMU {
     VFIOContainer *container;
-    MemoryRegion *iommu;
+    IOMMUMemoryRegion *iommu;
     hwaddr iommu_offset;
     IOMMUNotifier n;
     QLIST_ENTRY(VFIOGuestIOMMU) giommu_next;
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index 2706aabedf..b19159104c 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -45,6 +45,7 @@ typedef struct MachineState MachineState;
 typedef struct MemoryListener MemoryListener;
 typedef struct MemoryMappingList MemoryMappingList;
 typedef struct MemoryRegion MemoryRegion;
+typedef struct IOMMUMemoryRegion IOMMUMemoryRegion;
 typedef struct MemoryRegionCache MemoryRegionCache;
 typedef struct MemoryRegionSection MemoryRegionSection;
 typedef struct MigrationIncomingState MigrationIncomingState;
diff --git a/exec.c b/exec.c
index a083ff89ad..5135c9ef62 100644
--- a/exec.c
+++ b/exec.c
@@ -480,19 +480,19 @@ static MemoryRegionSection address_space_do_translate(AddressSpace *as,
 {
     IOMMUTLBEntry iotlb;
     MemoryRegionSection *section;
-    MemoryRegion *mr;
+    IOMMUMemoryRegion *iommu_mr;
 
     for (;;) {
         AddressSpaceDispatch *d = atomic_rcu_read(&as->dispatch);
         section = address_space_translate_internal(d, addr, &addr, plen, is_mmio);
-        mr = section->mr;
 
-        if (!mr->iommu_ops) {
+        iommu_mr = memory_region_get_iommu(section->mr);
+        if (!iommu_mr) {
             break;
         }
 
-        iotlb = mr->iommu_ops->translate(mr, addr, is_write ?
-                                         IOMMU_WO : IOMMU_RO);
+        iotlb = iommu_mr->iommu_ops->translate(iommu_mr, addr, is_write ?
+                                               IOMMU_WO : IOMMU_RO);
         addr = ((iotlb.translated_addr & ~iotlb.addr_mask)
                 | (addr & iotlb.addr_mask));
         *plen = MIN(*plen, (addr | iotlb.addr_mask) - addr + 1);
@@ -588,7 +588,7 @@ address_space_translate_for_iotlb(CPUState *cpu, int asidx, hwaddr addr,
 
     section = address_space_translate_internal(d, addr, xlat, plen, false);
 
-    assert(!section->mr->iommu_ops);
+    assert(!memory_region_is_iommu(section->mr));
     return section;
 }
 #endif
diff --git a/hw/alpha/typhoon.c b/hw/alpha/typhoon.c
index c1cf7802a4..dd47b4569f 100644
--- a/hw/alpha/typhoon.c
+++ b/hw/alpha/typhoon.c
@@ -41,7 +41,7 @@ typedef struct TyphoonPchip {
     MemoryRegion reg_conf;
 
     AddressSpace iommu_as;
-    MemoryRegion iommu;
+    IOMMUMemoryRegion iommu;
 
     uint64_t ctl;
     TyphoonWindow win[4];
@@ -663,7 +663,8 @@ static bool window_translate(TyphoonWindow *win, hwaddr addr,
 /* Handle PCI-to-system address translation.  */
 /* TODO: A translation failure here ought to set PCI error codes on the
    Pchip and generate a machine check interrupt.  */
-static IOMMUTLBEntry typhoon_translate_iommu(MemoryRegion *iommu, hwaddr addr,
+static IOMMUTLBEntry typhoon_translate_iommu(IOMMUMemoryRegion *iommu,
+                                             hwaddr addr,
                                              IOMMUAccessFlags flag)
 {
     TyphoonPchip *pchip = container_of(iommu, TyphoonPchip, iommu);
@@ -893,7 +894,8 @@ PCIBus *typhoon_init(ram_addr_t ram_size, ISABus **isa_bus,
     /* Host memory as seen from the PCI side, via the IOMMU.  */
     memory_region_init_iommu(&s->pchip.iommu, OBJECT(s), &typhoon_iommu_ops,
                              "iommu-typhoon", UINT64_MAX);
-    address_space_init(&s->pchip.iommu_as, &s->pchip.iommu, "pchip0-pci");
+    address_space_init(&s->pchip.iommu_as, MEMORY_REGION(&s->pchip.iommu),
+                       "pchip0-pci");
     pci_setup_iommu(b, typhoon_pci_dma_iommu, s);
 
     /* Pchip0 PCI special/interrupt acknowledge, 0x801.F800.0000, 64MB.  */
diff --git a/hw/dma/rc4030.c b/hw/dma/rc4030.c
index edf9432051..32c06760ef 100644
--- a/hw/dma/rc4030.c
+++ b/hw/dma/rc4030.c
@@ -90,7 +90,7 @@ typedef struct rc4030State
     qemu_irq jazz_bus_irq;
 
     /* whole DMA memory region, root of DMA address space */
-    MemoryRegion dma_mr;
+    IOMMUMemoryRegion dma_mr;
     AddressSpace dma_as;
 
     MemoryRegion iomem_chipset;
@@ -488,7 +488,7 @@ static const MemoryRegionOps jazzio_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static IOMMUTLBEntry rc4030_dma_translate(MemoryRegion *iommu, hwaddr addr,
+static IOMMUTLBEntry rc4030_dma_translate(IOMMUMemoryRegion *iommu, hwaddr addr,
                                           IOMMUAccessFlags flag)
 {
     rc4030State *s = container_of(iommu, rc4030State, dma_mr);
@@ -679,7 +679,7 @@ static void rc4030_realize(DeviceState *dev, Error **errp)
 
     memory_region_init_iommu(&s->dma_mr, o, &rc4030_dma_ops,
                              "rc4030.dma", UINT32_MAX);
-    address_space_init(&s->dma_as, &s->dma_mr, "rc4030-dma");
+    address_space_init(&s->dma_as, MEMORY_REGION(&s->dma_mr), "rc4030-dma");
 }
 
 static void rc4030_unrealize(DeviceState *dev, Error **errp)
@@ -717,7 +717,7 @@ static void rc4030_register_types(void)
 
 type_init(rc4030_register_types)
 
-DeviceState *rc4030_init(rc4030_dma **dmas, MemoryRegion **dma_mr)
+DeviceState *rc4030_init(rc4030_dma **dmas, IOMMUMemoryRegion **dma_mr)
 {
     DeviceState *dev;
 
diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index d93ffc2a15..7a67c573af 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -52,7 +52,7 @@ struct AMDVIAddressSpace {
     uint8_t bus_num;            /* bus number                           */
     uint8_t devfn;              /* device function                      */
     AMDVIState *iommu_state;    /* AMDVI - one per machine              */
-    MemoryRegion iommu;         /* Device's address translation region  */
+    IOMMUMemoryRegion iommu;    /* Device's address translation region  */
     MemoryRegion iommu_ir;      /* Device's interrupt remapping region  */
     AddressSpace as;            /* device's corresponding address space */
 };
@@ -987,7 +987,7 @@ static inline bool amdvi_is_interrupt_addr(hwaddr addr)
     return addr >= AMDVI_INT_ADDR_FIRST && addr <= AMDVI_INT_ADDR_LAST;
 }
 
-static IOMMUTLBEntry amdvi_translate(MemoryRegion *iommu, hwaddr addr,
+static IOMMUTLBEntry amdvi_translate(IOMMUMemoryRegion *iommu, hwaddr addr,
                                      IOMMUAccessFlags flag)
 {
     AMDVIAddressSpace *as = container_of(iommu, AMDVIAddressSpace, iommu);
@@ -1046,7 +1046,8 @@ static AddressSpace *amdvi_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
 
         memory_region_init_iommu(&iommu_as[devfn]->iommu, OBJECT(s),
                                  &s->iommu_ops, "amd-iommu", UINT64_MAX);
-        address_space_init(&iommu_as[devfn]->as, &iommu_as[devfn]->iommu,
+        address_space_init(&iommu_as[devfn]->as,
+                           MEMORY_REGION(&iommu_as[devfn]->iommu),
                            "amd-iommu");
     }
     return &iommu_as[devfn]->as;
@@ -1067,7 +1068,7 @@ static const MemoryRegionOps mmio_mem_ops = {
     }
 };
 
-static void amdvi_iommu_notify_flag_changed(MemoryRegion *iommu,
+static void amdvi_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
                                             IOMMUNotifierFlag old,
                                             IOMMUNotifierFlag new)
 {
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 88dc042b5c..11dba0e274 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -972,9 +972,9 @@ static bool vtd_switch_address_space(VTDAddressSpace *as)
     /* Turn off first then on the other */
     if (use_iommu) {
         memory_region_set_enabled(&as->sys_alias, false);
-        memory_region_set_enabled(&as->iommu, true);
+        memory_region_set_enabled(MEMORY_REGION(&as->iommu), true);
     } else {
-        memory_region_set_enabled(&as->iommu, false);
+        memory_region_set_enabled(MEMORY_REGION(&as->iommu), false);
         memory_region_set_enabled(&as->sys_alias, true);
     }
 
@@ -1366,7 +1366,7 @@ static void vtd_iotlb_domain_invalidate(IntelIOMMUState *s, uint16_t domain_id)
 static int vtd_page_invalidate_notify_hook(IOMMUTLBEntry *entry,
                                            void *private)
 {
-    memory_region_notify_iommu((MemoryRegion *)private, *entry);
+    memory_region_notify_iommu((IOMMUMemoryRegion *)private, *entry);
     return 0;
 }
 
@@ -2264,7 +2264,7 @@ static void vtd_mem_write(void *opaque, hwaddr addr,
     }
 }
 
-static IOMMUTLBEntry vtd_iommu_translate(MemoryRegion *iommu, hwaddr addr,
+static IOMMUTLBEntry vtd_iommu_translate(IOMMUMemoryRegion *iommu, hwaddr addr,
                                          IOMMUAccessFlags flag)
 {
     VTDAddressSpace *vtd_as = container_of(iommu, VTDAddressSpace, iommu);
@@ -2303,7 +2303,7 @@ static IOMMUTLBEntry vtd_iommu_translate(MemoryRegion *iommu, hwaddr addr,
     return iotlb;
 }
 
-static void vtd_iommu_notify_flag_changed(MemoryRegion *iommu,
+static void vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
                                           IOMMUNotifierFlag old,
                                           IOMMUNotifierFlag new)
 {
@@ -2736,7 +2736,8 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn)
         memory_region_add_subregion_overlap(&vtd_dev_as->root, 0,
                                             &vtd_dev_as->sys_alias, 1);
         memory_region_add_subregion_overlap(&vtd_dev_as->root, 0,
-                                            &vtd_dev_as->iommu, 1);
+                                            MEMORY_REGION(&vtd_dev_as->iommu),
+                                            1);
         vtd_switch_address_space(vtd_dev_as);
     }
     return vtd_dev_as;
@@ -2816,9 +2817,9 @@ static int vtd_replay_hook(IOMMUTLBEntry *entry, void *private)
     return 0;
 }
 
-static void vtd_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n)
+static void vtd_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n)
 {
-    VTDAddressSpace *vtd_as = container_of(mr, VTDAddressSpace, iommu);
+    VTDAddressSpace *vtd_as = container_of(iommu_mr, VTDAddressSpace, iommu);
     IntelIOMMUState *s = vtd_as->iommu_state;
     uint8_t bus_n = pci_bus_num(vtd_as->bus);
     VTDContextEntry ce;
diff --git a/hw/mips/mips_jazz.c b/hw/mips/mips_jazz.c
index 1cef581878..1f69322c15 100644
--- a/hw/mips/mips_jazz.c
+++ b/hw/mips/mips_jazz.c
@@ -130,7 +130,7 @@ static void mips_jazz_init(MachineState *machine,
     CPUMIPSState *env;
     qemu_irq *i8259;
     rc4030_dma *dmas;
-    MemoryRegion *rc4030_dma_mr;
+    IOMMUMemoryRegion *rc4030_dma_mr;
     MemoryRegion *isa_mem = g_new(MemoryRegion, 1);
     MemoryRegion *isa_io = g_new(MemoryRegion, 1);
     MemoryRegion *rtc = g_new(MemoryRegion, 1);
diff --git a/hw/pci-host/apb.c b/hw/pci-host/apb.c
index 326f5ef024..76a56ae29b 100644
--- a/hw/pci-host/apb.c
+++ b/hw/pci-host/apb.c
@@ -123,7 +123,7 @@ do { printf("IOMMU: " fmt , ## __VA_ARGS__); } while (0)
 
 typedef struct IOMMUState {
     AddressSpace iommu_as;
-    MemoryRegion iommu;
+    IOMMUMemoryRegion iommu;
 
     uint64_t regs[IOMMU_NREGS];
 } IOMMUState;
@@ -208,7 +208,7 @@ static AddressSpace *pbm_pci_dma_iommu(PCIBus *bus, void *opaque, int devfn)
 }
 
 /* Called from RCU critical section */
-static IOMMUTLBEntry pbm_translate_iommu(MemoryRegion *iommu, hwaddr addr,
+static IOMMUTLBEntry pbm_translate_iommu(IOMMUMemoryRegion *iommu, hwaddr addr,
                                          IOMMUAccessFlags flag)
 {
     IOMMUState *is = container_of(iommu, IOMMUState, iommu);
@@ -699,7 +699,7 @@ PCIBus *pci_apb_init(hwaddr special_base,
 
     memory_region_init_iommu(&is->iommu, OBJECT(dev), &pbm_iommu_ops,
                              "iommu-apb", UINT64_MAX);
-    address_space_init(&is->iommu_as, &is->iommu, "pbm-as");
+    address_space_init(&is->iommu_as, MEMORY_REGION(&is->iommu), "pbm-as");
     pci_setup_iommu(phb->bus, pbm_pci_dma_iommu, is);
 
     /* APB secondary busses */
diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
index 8656a54a3e..6b6ced5710 100644
--- a/hw/ppc/spapr_iommu.c
+++ b/hw/ppc/spapr_iommu.c
@@ -110,7 +110,8 @@ static void spapr_tce_free_table(uint64_t *table, int fd, uint32_t nb_table)
 }
 
 /* Called from RCU critical section */
-static IOMMUTLBEntry spapr_tce_translate_iommu(MemoryRegion *iommu, hwaddr addr,
+static IOMMUTLBEntry spapr_tce_translate_iommu(IOMMUMemoryRegion *iommu,
+                                               hwaddr addr,
                                                IOMMUAccessFlags flag)
 {
     sPAPRTCETable *tcet = container_of(iommu, sPAPRTCETable, iommu);
@@ -150,14 +151,14 @@ static void spapr_tce_table_pre_save(void *opaque)
                                tcet->bus_offset, tcet->page_shift);
 }
 
-static uint64_t spapr_tce_get_min_page_size(MemoryRegion *iommu)
+static uint64_t spapr_tce_get_min_page_size(IOMMUMemoryRegion *iommu)
 {
     sPAPRTCETable *tcet = container_of(iommu, sPAPRTCETable, iommu);
 
     return 1ULL << tcet->page_shift;
 }
 
-static void spapr_tce_notify_flag_changed(MemoryRegion *iommu,
+static void spapr_tce_notify_flag_changed(IOMMUMemoryRegion *iommu,
                                           IOMMUNotifierFlag old,
                                           IOMMUNotifierFlag new)
 {
@@ -348,9 +349,10 @@ void spapr_tce_table_enable(sPAPRTCETable *tcet,
                                         &tcet->fd,
                                         tcet->need_vfio);
 
-    memory_region_set_size(&tcet->iommu,
+    memory_region_set_size(MEMORY_REGION(&tcet->iommu),
                            (uint64_t)tcet->nb_table << tcet->page_shift);
-    memory_region_add_subregion(&tcet->root, tcet->bus_offset, &tcet->iommu);
+    memory_region_add_subregion(&tcet->root, tcet->bus_offset,
+                                MEMORY_REGION(&tcet->iommu));
 }
 
 void spapr_tce_table_disable(sPAPRTCETable *tcet)
@@ -359,8 +361,8 @@ void spapr_tce_table_disable(sPAPRTCETable *tcet)
         return;
     }
 
-    memory_region_del_subregion(&tcet->root, &tcet->iommu);
-    memory_region_set_size(&tcet->iommu, 0);
+    memory_region_del_subregion(&tcet->root, MEMORY_REGION(&tcet->iommu));
+    memory_region_set_size(MEMORY_REGION(&tcet->iommu), 0);
 
     spapr_tce_free_table(tcet->table, tcet->fd, tcet->nb_table);
     tcet->fd = -1;
diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 5651483781..e4fc82cbe1 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -356,7 +356,7 @@ out:
     return pte;
 }
 
-static IOMMUTLBEntry s390_translate_iommu(MemoryRegion *mr, hwaddr addr,
+static IOMMUTLBEntry s390_translate_iommu(IOMMUMemoryRegion *mr, hwaddr addr,
                                           IOMMUAccessFlags flag)
 {
     uint64_t pte;
@@ -525,14 +525,14 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu)
     memory_region_init_iommu(&iommu->iommu_mr, OBJECT(&iommu->mr),
                              &s390_iommu_ops, name, iommu->pal + 1);
     iommu->enabled = true;
-    memory_region_add_subregion(&iommu->mr, 0, &iommu->iommu_mr);
+    memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr));
     g_free(name);
 }
 
 void s390_pci_iommu_disable(S390PCIIOMMU *iommu)
 {
     iommu->enabled = false;
-    memory_region_del_subregion(&iommu->mr, &iommu->iommu_mr);
+    memory_region_del_subregion(&iommu->mr, MEMORY_REGION(&iommu->iommu_mr));
     object_unparent(OBJECT(&iommu->iommu_mr));
 }
 
diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index 8bc7c98682..a53c29c487 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -563,7 +563,7 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
     S390PCIIOMMU *iommu;
     hwaddr start, end;
     IOMMUTLBEntry entry;
-    MemoryRegion *mr;
+    IOMMUMemoryRegion *iommu_mr;
 
     cpu_synchronize_state(CPU(cpu));
 
@@ -622,9 +622,9 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
         goto out;
     }
 
-    mr = &iommu->iommu_mr;
+    iommu_mr = &iommu->iommu_mr;
     while (start < end) {
-        entry = mr->iommu_ops->translate(mr, start, IOMMU_NONE);
+        entry = iommu_mr->iommu_ops->translate(iommu_mr, start, IOMMU_NONE);
 
         if (!entry.translated_addr) {
             pbdev->state = ZPCI_FS_ERROR;
@@ -635,7 +635,7 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
             goto out;
         }
 
-        memory_region_notify_iommu(mr, entry);
+        memory_region_notify_iommu(iommu_mr, entry);
         start += entry.addr_mask + 1;
     }
 
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index b9abe77f5a..2965b68e5d 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -479,6 +479,7 @@ static void vfio_listener_region_add(MemoryListener *listener,
 
     if (memory_region_is_iommu(section->mr)) {
         VFIOGuestIOMMU *giommu;
+        IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr);
 
         trace_vfio_listener_region_add_iommu(iova, end);
         /*
@@ -488,7 +489,7 @@ static void vfio_listener_region_add(MemoryListener *listener,
          * device emulation the VFIO iommu handles to use).
          */
         giommu = g_malloc0(sizeof(*giommu));
-        giommu->iommu = section->mr;
+        giommu->iommu = iommu_mr;
         giommu->iommu_offset = section->offset_within_address_space -
                                section->offset_within_region;
         giommu->container = container;
@@ -501,7 +502,7 @@ static void vfio_listener_region_add(MemoryListener *listener,
                             int128_get64(llend));
         QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
 
-        memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
+        memory_region_register_iommu_notifier(section->mr, &giommu->n);
         memory_region_iommu_replay(giommu->iommu, &giommu->n);
 
         return;
@@ -569,9 +570,9 @@ static void vfio_listener_region_del(MemoryListener *listener,
         VFIOGuestIOMMU *giommu;
 
         QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
-            if (giommu->iommu == section->mr &&
+            if (MEMORY_REGION(giommu->iommu) == section->mr &&
                 giommu->n.start == section->offset_within_region) {
-                memory_region_unregister_iommu_notifier(giommu->iommu,
+                memory_region_unregister_iommu_notifier(section->mr,
                                                         &giommu->n);
                 QLIST_REMOVE(giommu, giommu_next);
                 g_free(giommu);
@@ -1161,7 +1162,8 @@ static void vfio_disconnect_container(VFIOGroup *group)
         QLIST_REMOVE(container, next);
 
         QLIST_FOREACH_SAFE(giommu, &container->giommu_list, giommu_next, tmp) {
-            memory_region_unregister_iommu_notifier(giommu->iommu, &giommu->n);
+            memory_region_unregister_iommu_notifier(
+                    MEMORY_REGION(giommu->iommu), &giommu->n);
             QLIST_REMOVE(giommu, giommu_next);
             g_free(giommu);
         }
diff --git a/hw/vfio/spapr.c b/hw/vfio/spapr.c
index 4409bcc0d7..32fd6a9b54 100644
--- a/hw/vfio/spapr.c
+++ b/hw/vfio/spapr.c
@@ -143,7 +143,8 @@ int vfio_spapr_create_window(VFIOContainer *container,
                              hwaddr *pgsize)
 {
     int ret;
-    unsigned pagesize = memory_region_iommu_get_min_page_size(section->mr);
+    IOMMUMemoryRegion *iommu_mr = IOMMU_MEMORY_REGION(section->mr);
+    unsigned pagesize = memory_region_iommu_get_min_page_size(iommu_mr);
     unsigned entries, pages;
     struct vfio_iommu_spapr_tce_create create = { .argsz = sizeof(create) };
 
diff --git a/memory.c b/memory.c
index 1044bbaf0c..45e10e2e3b 100644
--- a/memory.c
+++ b/memory.c
@@ -977,12 +977,11 @@ static char *memory_region_escape_name(const char *name)
     return escaped;
 }
 
-void memory_region_init(MemoryRegion *mr,
-                        Object *owner,
-                        const char *name,
-                        uint64_t size)
+static void memory_region_do_init(MemoryRegion *mr,
+                                  Object *owner,
+                                  const char *name,
+                                  uint64_t size)
 {
-    object_initialize(mr, sizeof(*mr), TYPE_MEMORY_REGION);
     mr->size = int128_make64(size);
     if (size == UINT64_MAX) {
         mr->size = int128_2_64();
@@ -1006,6 +1005,15 @@ void memory_region_init(MemoryRegion *mr,
     }
 }
 
+void memory_region_init(MemoryRegion *mr,
+                        Object *owner,
+                        const char *name,
+                        uint64_t size)
+{
+    object_initialize(mr, sizeof(*mr), TYPE_MEMORY_REGION);
+    memory_region_do_init(mr, owner, name, size);
+}
+
 static void memory_region_get_addr(Object *obj, Visitor *v, const char *name,
                                    void *opaque, Error **errp)
 {
@@ -1092,6 +1100,13 @@ static void memory_region_initfn(Object *obj)
                         NULL, NULL, &error_abort);
 }
 
+static void iommu_memory_region_initfn(Object *obj)
+{
+    MemoryRegion *mr = MEMORY_REGION(obj);
+
+    mr->is_iommu = true;
+}
+
 static uint64_t unassigned_mem_read(void *opaque, hwaddr addr,
                                     unsigned size)
 {
@@ -1491,17 +1506,22 @@ void memory_region_init_rom_device(MemoryRegion *mr,
     mr->ram_block = qemu_ram_alloc(size, mr, errp);
 }
 
-void memory_region_init_iommu(MemoryRegion *mr,
+void memory_region_init_iommu(IOMMUMemoryRegion *iommu_mr,
                               Object *owner,
                               const MemoryRegionIOMMUOps *ops,
                               const char *name,
                               uint64_t size)
 {
-    memory_region_init(mr, owner, name, size);
-    mr->iommu_ops = ops,
+    struct MemoryRegion *mr;
+
+    object_initialize(iommu_mr, sizeof(*iommu_mr), TYPE_IOMMU_MEMORY_REGION);
+    mr = MEMORY_REGION(iommu_mr);
+    memory_region_do_init(mr, owner, name, size);
+    iommu_mr = IOMMU_MEMORY_REGION(mr);
+    iommu_mr->iommu_ops = ops,
     mr->terminates = true;  /* then re-forwards */
-    QLIST_INIT(&mr->iommu_notify);
-    mr->iommu_notify_flags = IOMMU_NOTIFIER_NONE;
+    QLIST_INIT(&iommu_mr->iommu_notify);
+    iommu_mr->iommu_notify_flags = IOMMU_NOTIFIER_NONE;
 }
 
 static void memory_region_finalize(Object *obj)
@@ -1596,63 +1616,67 @@ bool memory_region_is_logging(MemoryRegion *mr, uint8_t client)
     return memory_region_get_dirty_log_mask(mr) & (1 << client);
 }
 
-static void memory_region_update_iommu_notify_flags(MemoryRegion *mr)
+static void memory_region_update_iommu_notify_flags(IOMMUMemoryRegion *iommu_mr)
 {
     IOMMUNotifierFlag flags = IOMMU_NOTIFIER_NONE;
     IOMMUNotifier *iommu_notifier;
 
-    IOMMU_NOTIFIER_FOREACH(iommu_notifier, mr) {
+    IOMMU_NOTIFIER_FOREACH(iommu_notifier, iommu_mr) {
         flags |= iommu_notifier->notifier_flags;
     }
 
-    if (flags != mr->iommu_notify_flags &&
-        mr->iommu_ops->notify_flag_changed) {
-        mr->iommu_ops->notify_flag_changed(mr, mr->iommu_notify_flags,
-                                           flags);
+    if (flags != iommu_mr->iommu_notify_flags &&
+        iommu_mr->iommu_ops->notify_flag_changed) {
+        iommu_mr->iommu_ops->notify_flag_changed(iommu_mr,
+                                                iommu_mr->iommu_notify_flags,
+                                                flags);
     }
 
-    mr->iommu_notify_flags = flags;
+    iommu_mr->iommu_notify_flags = flags;
 }
 
 void memory_region_register_iommu_notifier(MemoryRegion *mr,
                                            IOMMUNotifier *n)
 {
+    IOMMUMemoryRegion *iommu_mr;
+
     if (mr->alias) {
         memory_region_register_iommu_notifier(mr->alias, n);
         return;
     }
 
     /* We need to register for at least one bitfield */
+    iommu_mr = IOMMU_MEMORY_REGION(mr);
     assert(n->notifier_flags != IOMMU_NOTIFIER_NONE);
     assert(n->start <= n->end);
-    QLIST_INSERT_HEAD(&mr->iommu_notify, n, node);
-    memory_region_update_iommu_notify_flags(mr);
+    QLIST_INSERT_HEAD(&iommu_mr->iommu_notify, n, node);
+    memory_region_update_iommu_notify_flags(iommu_mr);
 }
 
-uint64_t memory_region_iommu_get_min_page_size(MemoryRegion *mr)
+uint64_t memory_region_iommu_get_min_page_size(IOMMUMemoryRegion *iommu_mr)
 {
-    assert(memory_region_is_iommu(mr));
-    if (mr->iommu_ops && mr->iommu_ops->get_min_page_size) {
-        return mr->iommu_ops->get_min_page_size(mr);
+    if (iommu_mr->iommu_ops && iommu_mr->iommu_ops->get_min_page_size) {
+        return iommu_mr->iommu_ops->get_min_page_size(iommu_mr);
     }
     return TARGET_PAGE_SIZE;
 }
 
-void memory_region_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n)
+void memory_region_iommu_replay(IOMMUMemoryRegion *iommu_mr, IOMMUNotifier *n)
 {
+    MemoryRegion *mr = MEMORY_REGION(iommu_mr);
     hwaddr addr, granularity;
     IOMMUTLBEntry iotlb;
 
     /* If the IOMMU has its own replay callback, override */
-    if (mr->iommu_ops->replay) {
-        mr->iommu_ops->replay(mr, n);
+    if (iommu_mr->iommu_ops->replay) {
+        iommu_mr->iommu_ops->replay(iommu_mr, n);
         return;
     }
 
-    granularity = memory_region_iommu_get_min_page_size(mr);
+    granularity = memory_region_iommu_get_min_page_size(iommu_mr);
 
     for (addr = 0; addr < memory_region_size(mr); addr += granularity) {
-        iotlb = mr->iommu_ops->translate(mr, addr, IOMMU_NONE);
+        iotlb = iommu_mr->iommu_ops->translate(iommu_mr, addr, IOMMU_NONE);
         if (iotlb.perm != IOMMU_NONE) {
             n->notify(n, &iotlb);
         }
@@ -1665,24 +1689,27 @@ void memory_region_iommu_replay(MemoryRegion *mr, IOMMUNotifier *n)
     }
 }
 
-void memory_region_iommu_replay_all(MemoryRegion *mr)
+void memory_region_iommu_replay_all(IOMMUMemoryRegion *iommu_mr)
 {
     IOMMUNotifier *notifier;
 
-    IOMMU_NOTIFIER_FOREACH(notifier, mr) {
-        memory_region_iommu_replay(mr, notifier);
+    IOMMU_NOTIFIER_FOREACH(notifier, iommu_mr) {
+        memory_region_iommu_replay(iommu_mr, notifier);
     }
 }
 
 void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
                                              IOMMUNotifier *n)
 {
+    IOMMUMemoryRegion *iommu_mr;
+
     if (mr->alias) {
         memory_region_unregister_iommu_notifier(mr->alias, n);
         return;
     }
     QLIST_REMOVE(n, node);
-    memory_region_update_iommu_notify_flags(mr);
+    iommu_mr = IOMMU_MEMORY_REGION(mr);
+    memory_region_update_iommu_notify_flags(iommu_mr);
 }
 
 void memory_region_notify_one(IOMMUNotifier *notifier,
@@ -1710,14 +1737,14 @@ void memory_region_notify_one(IOMMUNotifier *notifier,
     }
 }
 
-void memory_region_notify_iommu(MemoryRegion *mr,
+void memory_region_notify_iommu(IOMMUMemoryRegion *iommu_mr,
                                 IOMMUTLBEntry entry)
 {
     IOMMUNotifier *iommu_notifier;
 
-    assert(memory_region_is_iommu(mr));
+    assert(memory_region_is_iommu(MEMORY_REGION(iommu_mr)));
 
-    IOMMU_NOTIFIER_FOREACH(iommu_notifier, mr) {
+    IOMMU_NOTIFIER_FOREACH(iommu_notifier, iommu_mr) {
         memory_region_notify_one(iommu_notifier, &entry);
     }
 }
@@ -2825,9 +2852,17 @@ static const TypeInfo memory_region_info = {
     .instance_finalize  = memory_region_finalize,
 };
 
+static const TypeInfo iommu_memory_region_info = {
+    .parent             = TYPE_MEMORY_REGION,
+    .name               = TYPE_IOMMU_MEMORY_REGION,
+    .instance_size      = sizeof(IOMMUMemoryRegion),
+    .instance_init      = iommu_memory_region_initfn,
+};
+
 static void memory_register_types(void)
 {
     type_register_static(&memory_region_info);
+    type_register_static(&iommu_memory_region_info);
 }
 
 type_init(memory_register_types)
-- 
2.11.0