diff --git a/hw/core/machine.c b/hw/core/machine.c
index 6dbbc85..23456f8 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -286,20 +286,6 @@ static void machine_set_firmware(Object *obj, const char *value, Error **errp)
     ms->firmware = g_strdup(value);
 }
 
-static bool machine_get_iommu(Object *obj, Error **errp)
-{
-    MachineState *ms = MACHINE(obj);
-
-    return ms->iommu;
-}
-
-static void machine_set_iommu(Object *obj, bool value, Error **errp)
-{
-    MachineState *ms = MACHINE(obj);
-
-    ms->iommu = value;
-}
-
 static void machine_set_suppress_vmdesc(Object *obj, bool value, Error **errp)
 {
     MachineState *ms = MACHINE(obj);
@@ -472,12 +458,6 @@ static void machine_initfn(Object *obj)
     object_property_set_description(obj, "firmware",
                                     "Firmware image",
                                     NULL);
-    object_property_add_bool(obj, "iommu",
-                             machine_get_iommu,
-                             machine_set_iommu, NULL);
-    object_property_set_description(obj, "iommu",
-                                    "Set on/off to enable/disable Intel IOMMU (VT-d)",
-                                    NULL);
     object_property_add_bool(obj, "suppress-vmdesc",
                              machine_get_suppress_vmdesc,
                              machine_set_suppress_vmdesc, NULL);
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 347718f..9af5d6b 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -24,6 +24,8 @@
 #include "exec/address-spaces.h"
 #include "intel_iommu_internal.h"
 #include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/i386/pc.h"
 
 /*#define DEBUG_INTEL_IOMMU*/
 #ifdef DEBUG_INTEL_IOMMU
@@ -2014,8 +2016,20 @@ static void vtd_reset(DeviceState *dev)
     vtd_init(s);
 }
 
+static AddressSpace *vtd_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
+{
+    IntelIOMMUState *s = opaque;
+    VTDAddressSpace *vtd_as;
+
+    assert(0 <= devfn && devfn <= VTD_PCI_DEVFN_MAX);
+
+    vtd_as = vtd_find_add_as(s, bus, devfn);
+    return &vtd_as->as;
+}
+
 static void vtd_realize(DeviceState *dev, Error **errp)
 {
+    PCIBus *bus = PC_MACHINE(qdev_get_machine())->bus;
     IntelIOMMUState *s = INTEL_IOMMU_DEVICE(dev);
 
     VTD_DPRINTF(GENERAL, "");
@@ -2029,6 +2043,9 @@ static void vtd_realize(DeviceState *dev, Error **errp)
     s->vtd_as_by_busptr = g_hash_table_new_full(vtd_uint64_hash, vtd_uint64_equal,
                                               g_free, g_free);
     vtd_init(s);
+    sysbus_mmio_map(SYS_BUS_DEVICE(s), 0, Q35_HOST_BRIDGE_IOMMU_ADDR);
+    bus->iommu_fn = vtd_host_dma_iommu;
+    bus->iommu_opaque = dev;
 }
 
 static void vtd_class_init(ObjectClass *klass, void *data)
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 04aae89..431eaed 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -281,6 +281,7 @@ static void pc_q35_machine_options(MachineClass *m)
     m->default_machine_opts = "firmware=bios-256k.bin";
     m->default_display = "std";
     m->no_floppy = 1;
+    m->has_dynamic_sysbus = true;
 }
 
 static void pc_q35_2_6_machine_options(MachineClass *m)
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index 70f897e..ea684c7 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -424,30 +424,6 @@ static void mch_reset(DeviceState *qdev)
     mch_update(mch);
 }
 
-static AddressSpace *q35_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
-{
-    IntelIOMMUState *s = opaque;
-    VTDAddressSpace *vtd_as;
-
-    assert(0 <= devfn && devfn <= VTD_PCI_DEVFN_MAX);
-
-    vtd_as = vtd_find_add_as(s, bus, devfn);
-    return &vtd_as->as;
-}
-
-static void mch_init_dmar(MCHPCIState *mch)
-{
-    PCIBus *pci_bus = PCI_BUS(qdev_get_parent_bus(DEVICE(mch)));
-
-    mch->iommu = INTEL_IOMMU_DEVICE(qdev_create(NULL, TYPE_INTEL_IOMMU_DEVICE));
-    object_property_add_child(OBJECT(mch), "intel-iommu",
-                              OBJECT(mch->iommu), NULL);
-    qdev_init_nofail(DEVICE(mch->iommu));
-    sysbus_mmio_map(SYS_BUS_DEVICE(mch->iommu), 0, Q35_HOST_BRIDGE_IOMMU_ADDR);
-
-    pci_setup_iommu(pci_bus, q35_host_dma_iommu, mch->iommu);
-}
-
 static void mch_realize(PCIDevice *d, Error **errp)
 {
     int i;
@@ -506,10 +482,6 @@ static void mch_realize(PCIDevice *d, Error **errp)
                  mch->pci_address_space, &mch->pam_regions[i+1],
                  PAM_EXPAN_BASE + i * PAM_EXPAN_SIZE, PAM_EXPAN_SIZE);
     }
-    /* Intel IOMMU (VT-d) */
-    if (object_property_get_bool(qdev_get_machine(), "iommu", NULL)) {
-        mch_init_dmar(mch);
-    }
 }
 
 uint64_t mch_mcfg_base(void)
