diff --git a/hw/dimm.c b/hw/dimm.c
new file mode 100644
index 0000000..288b997
--- /dev/null
+++ b/hw/dimm.c
@@ -0,0 +1,305 @@
+/*
+ * Dimm device for Memory Hotplug
+ *
+ * Copyright ProfitBricks GmbH 2012
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ */
+
+#include "trace.h"
+#include "qdev.h"
+#include "dimm.h"
+#include <time.h>
+#include "../exec-memory.h"
+#include "qmp-commands.h"
+
+/* the system-wide memory bus. */
+static DimmBus *main_memory_bus;
+/* the following list is used to hold dimm config info before machine
+ * initialization. After machine init, the list is emptied and not used anymore.*/
+static DimmConfiglist dimmconfig_list = QTAILQ_HEAD_INITIALIZER(dimmconfig_list);
+
+static void dimmbus_dev_print(Monitor *mon, DeviceState *dev, int indent);
+static char *dimmbus_get_fw_dev_path(DeviceState *dev);
+
+static Property dimm_properties[] = {
+    DEFINE_PROP_UINT64("start", DimmDevice, start, 0),
+    DEFINE_PROP_UINT64("size", DimmDevice, size, DEFAULT_DIMMSIZE),
+    DEFINE_PROP_UINT32("node", DimmDevice, node, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void dimmbus_dev_print(Monitor *mon, DeviceState *dev, int indent)
+{
+}
+
+static char *dimmbus_get_fw_dev_path(DeviceState *dev)
+{
+    char path[40];
+
+    snprintf(path, sizeof(path), "%s", qdev_fw_name(dev));
+    return strdup(path);
+}
+
+static void dimm_bus_class_init(ObjectClass *klass, void *data)
+{
+    BusClass *k = BUS_CLASS(klass);
+
+    k->print_dev = dimmbus_dev_print;
+    k->get_fw_dev_path = dimmbus_get_fw_dev_path;
+}
+
+static void dimm_bus_initfn(Object *obj)
+{
+    DimmConfig *dimm_cfg, *next_dimm_cfg;
+    DimmBus *bus = DIMM_BUS(obj);
+    QTAILQ_INIT(&bus->dimmconfig_list);
+    QTAILQ_INIT(&bus->dimmlist);
+
+    QTAILQ_FOREACH_SAFE(dimm_cfg, &dimmconfig_list, nextdimmcfg, next_dimm_cfg) {
+        QTAILQ_REMOVE(&dimmconfig_list, dimm_cfg, nextdimmcfg);
+        QTAILQ_INSERT_TAIL(&bus->dimmconfig_list, dimm_cfg, nextdimmcfg);
+    }
+}
+
+static const TypeInfo dimm_bus_info = {
+    .name = TYPE_DIMM_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(DimmBus),
+    .instance_init = dimm_bus_initfn,
+    .class_init = dimm_bus_class_init,
+};
+
+void main_memory_bus_create(Object *parent)
+{
+    main_memory_bus = g_malloc0(dimm_bus_info.instance_size);
+    main_memory_bus->qbus.glib_allocated = true;
+    qbus_create_inplace(&main_memory_bus->qbus, TYPE_DIMM_BUS, DEVICE(parent),
+                        "membus");
+}
+
+static void dimm_populate(DimmDevice *s)
+{
+    DeviceState *dev= (DeviceState*)s;
+    MemoryRegion *new = NULL;
+
+    new = g_malloc(sizeof(MemoryRegion));
+    memory_region_init_ram(new, dev->id, s->size);
+    vmstate_register_ram_global(new);
+    memory_region_add_subregion(get_system_memory(), s->start, new);
+    s->mr = new;
+}
+
+static void dimm_depopulate(DimmDevice *s)
+{
+    assert(s);
+    vmstate_unregister_ram(s->mr, NULL);
+    memory_region_del_subregion(get_system_memory(), s->mr);
+    memory_region_destroy(s->mr);
+    s->mr = NULL;
+}
+
+void dimm_config_create(char *id, uint64_t size, uint64_t node, uint32_t
+        dimm_idx, uint32_t populated)
+{
+    DimmConfig *dimm_cfg;
+    dimm_cfg = (DimmConfig*) g_malloc0(sizeof(DimmConfig));
+    dimm_cfg->name = id;
+    dimm_cfg->idx = dimm_idx;
+    dimm_cfg->start = 0;
+    dimm_cfg->size = size;
+    dimm_cfg->node = node;
+    dimm_cfg->populated = populated;
+
+    QTAILQ_INSERT_TAIL(&dimmconfig_list, dimm_cfg, nextdimmcfg);
+}
+
+void dimm_bus_hotplug(dimm_hotplug_fn hotplug, DeviceState *qdev)
+{
+    DimmBus *bus = main_memory_bus;
+    bus->qbus.allow_hotplug = 1;
+    bus->dimm_hotplug_qdev = qdev;
+    bus->dimm_hotplug = hotplug;
+}
+
+static void dimm_plug_device(DimmDevice *slot)
+{
+    DimmBus *bus = main_memory_bus;
+
+    dimm_populate(slot);
+    if (bus->dimm_hotplug)
+        bus->dimm_hotplug(bus->dimm_hotplug_qdev, slot, 1);
+}
+
+static int dimm_unplug_device(DeviceState *qdev)
+{
+    DimmBus *bus = main_memory_bus;
+
+    if (bus->dimm_hotplug)
+        bus->dimm_hotplug(bus->dimm_hotplug_qdev, DIMM(qdev), 0);
+    return 1;
+}
+
+static DimmConfig *dimmcfg_find_from_name(const char *name)
+{
+    DimmConfig *slot;
+    DimmBus *bus = main_memory_bus;
+
+    QTAILQ_FOREACH(slot, &bus->dimmconfig_list, nextdimmcfg) {
+        if (!strcmp(slot->name, name)) {
+            return slot;
+        }
+    }
+    return NULL;
+}
+
+static DimmDevice *dimm_find_from_idx(uint32_t idx)
+{
+    DimmDevice *slot;
+    DimmBus *bus = main_memory_bus;
+
+    QTAILQ_FOREACH(slot, &bus->dimmlist, nextdimm) {
+        if (slot->idx == idx) {
+            return slot;
+        }
+    }
+    return NULL;
+}
+
+/* used to create a dimm device, only on incoming migration of a hotplugged
+ * RAMBlock
+ */
+int dimm_add(char *id)
+{
+    DimmConfig *slotcfg = NULL;
+    QemuOpts *devopts;
+    char buf[256];
+
+    if (!id) {
+        fprintf(stderr, "ERROR %s invalid id\n",__FUNCTION__);
+        return 1;
+    }
+
+    slotcfg = dimmcfg_find_from_name(id);
+
+    if (!slotcfg) {
+        fprintf(stderr, "%s no slot %s found\n", __FUNCTION__, id);
+        return 1;
+    }
+
+    devopts = qemu_opts_create(qemu_find_opts("device"), id, 0, NULL);
+    qemu_opt_set(devopts, "driver", "dimm");
+
+    snprintf(buf, sizeof(buf), "%lu", slotcfg->size);
+    qemu_opt_set(devopts, "size", buf);
+    snprintf(buf, sizeof(buf), "%u", slotcfg->node);
+    qemu_opt_set(devopts, "node", buf);
+    qdev_device_add(devopts);
+
+    return 0;
+}
+
+/* used to calculate physical address offsets for all dimms */
+void dimm_calc_offsets(dimm_calcoffset_fn calcfn)
+{
+    DimmConfig *slot;
+    QTAILQ_FOREACH(slot, &dimmconfig_list, nextdimmcfg) {
+        if (!slot->start) {
+            slot->start = calcfn(slot->size);
+        }
+    }
+}
+
+void setup_fwcfg_hp_dimms(uint64_t *fw_cfg_slots)
+{
+    DimmConfig *slot;
+
+    QTAILQ_FOREACH(slot, &dimmconfig_list, nextdimmcfg) {
+        assert(slot->start);
+        fw_cfg_slots[3 * slot->idx] = cpu_to_le64(slot->start);
+        fw_cfg_slots[3 * slot->idx + 1] = cpu_to_le64(slot->size);
+        fw_cfg_slots[3 * slot->idx + 2] = cpu_to_le64(slot->node);
+    }
+}
+
+void dimm_notify(uint32_t idx, uint32_t event)
+{
+    DimmBus *bus = main_memory_bus;
+    DimmDevice *s;
+    s = dimm_find_from_idx(idx);
+    assert(s != NULL);
+
+    switch(event) {
+        case DIMM_REMOVE_SUCCESS:
+            dimm_depopulate(s);
+            qdev_simple_unplug_cb((DeviceState*)s);
+            QTAILQ_REMOVE(&bus->dimmlist, s, nextdimm);
+            break;
+        default:
+            break;
+    }
+}
+
+static int dimm_init(DeviceState *s)
+{
+    DimmBus *bus = main_memory_bus;
+    DimmDevice *slot;
+    DimmConfig *slotcfg;
+
+    slot = DIMM(s);
+    slot->mr = NULL;
+
+    slotcfg = dimmcfg_find_from_name(s->id);
+
+    if (!slotcfg) {
+        fprintf(stderr, "%s no config for slot %s found\n",
+                __FUNCTION__, s->id);
+        return 1;
+    }
+
+    slot->idx = slotcfg->idx;
+    assert(slotcfg->start);
+    slot->start = slotcfg->start;
+    slot->size = slotcfg->size;
+    slot->node = slotcfg->node;
+
+    QTAILQ_INSERT_TAIL(&bus->dimmlist, slot, nextdimm);
+    dimm_plug_device(slot);
+
+    return 0;
+}
+
+
+static void dimm_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->props = dimm_properties;
+    dc->unplug = dimm_unplug_device;
+    dc->init = dimm_init;
+}
+
+static TypeInfo dimm_info = {
+    .name          = TYPE_DIMM,
+    .parent        = TYPE_DEVICE,
+    .instance_size = sizeof(DimmDevice),
+    .class_init    = dimm_class_init,
+};
+
+static void dimm_register_types(void)
+{
+    type_register_static(&dimm_bus_info);
+    type_register_static(&dimm_info);
+}
+
+type_init(dimm_register_types)
diff --git a/hw/dimm.h b/hw/dimm.h
new file mode 100644
index 0000000..5e991a6
--- /dev/null
+++ b/hw/dimm.h
@@ -0,0 +1,90 @@
+#ifndef QEMU_DIMM_H
+#define QEMU_DIMM_H
+
+#include "qemu-common.h"
+#include "memory.h"
+#include "sysbus.h"
+#include "qapi-types.h"
+#include "qemu-queue.h"
+#include "cpus.h"
+#define MAX_DIMMS 255
+#define DIMM_BITMAP_BYTES (MAX_DIMMS + 7) / 8
+#define DEFAULT_DIMMSIZE 1024*1024*1024
+
+typedef enum {
+    DIMM_REMOVE_SUCCESS = 0,
+    DIMM_REMOVE_FAIL = 1,
+    DIMM_ADD_SUCCESS = 2,
+    DIMM_ADD_FAIL = 3
+} dimm_hp_result_code;
+
+#define TYPE_DIMM "dimm"
+#define DIMM(obj) \
+    OBJECT_CHECK(DimmDevice, (obj), TYPE_DIMM)
+#define DIMM_CLASS(klass) \
+    OBJECT_CLASS_CHECK(DimmDeviceClass, (klass), TYPE_DIMM)
+#define DIMM_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(DimmDeviceClass, (obj), TYPE_DIMM)
+
+typedef struct DimmDevice DimmDevice;
+typedef QTAILQ_HEAD(DimmConfiglist, DimmConfig) DimmConfiglist;
+
+typedef struct DimmDeviceClass {
+    DeviceClass parent_class;
+
+    int (*init)(DimmDevice *dev);
+} DimmDeviceClass;
+
+typedef struct DimmDevice {
+    DeviceState qdev;
+    uint32_t idx; /* index in memory hotplug register/bitmap */
+    ram_addr_t start; /* starting physical address */
+    ram_addr_t size;
+    uint32_t node; /* numa node proximity */
+    MemoryRegion *mr; /* MemoryRegion for this slot. !NULL only if populated */
+    QTAILQ_ENTRY (DimmDevice) nextdimm;
+} DimmDevice;
+
+typedef struct DimmConfig
+{
+    const char *name;
+    uint32_t idx; /* index in memory hotplug register/bitmap */
+    ram_addr_t start; /* starting physical address */
+    ram_addr_t size;
+    uint32_t node; /* numa node proximity */
+    uint32_t populated; /* 1 means device has been hotplugged. Default is 0. */
+    QTAILQ_ENTRY (DimmConfig) nextdimmcfg;
+} DimmConfig;
+
+typedef int (*dimm_hotplug_fn)(DeviceState *qdev, DimmDevice *dev, int add);
+typedef target_phys_addr_t (*dimm_calcoffset_fn)(uint64_t size);
+
+#define TYPE_DIMM_BUS "dimmbus"
+#define DIMM_BUS(obj) OBJECT_CHECK(DimmBus, (obj), TYPE_DIMM_BUS)
+
+typedef struct DimmBus {
+    BusState qbus;
+    DeviceState *dimm_hotplug_qdev;
+    dimm_hotplug_fn dimm_hotplug;
+    dimm_calcoffset_fn dimm_calcoffset;
+    DimmConfiglist dimmconfig_list;
+    QTAILQ_HEAD(Dimmlist, DimmDevice) dimmlist;
+} DimmBus;
+
+struct dimm_hp_result {
+    const char *dimmname;
+    dimm_hp_result_code ret;
+    QTAILQ_ENTRY (dimm_hp_result) next;
+};
+
+void dimm_calc_offsets(dimm_calcoffset_fn calcfn);
+void dimm_notify(uint32_t idx, uint32_t event);
+void dimm_bus_hotplug(dimm_hotplug_fn hotplug, DeviceState *qdev);
+void setup_fwcfg_hp_dimms(uint64_t *fw_cfg_slots);
+int dimm_add(char *id);
+void main_memory_bus_create(Object *parent);
+void dimm_config_create(char *id, uint64_t size, uint64_t node,
+        uint32_t dimm_idx, uint32_t populated);
+
+
+#endif
