hw/mem/pc-dimm.c - qemu - Git at Google

 /*
  * Dimm device for Memory Hotplug
  *
  * Copyright ProfitBricks GmbH 2012
  * Copyright (C) 2014 Red Hat Inc
  *
  * 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 "qemu/osdep.h"
 #include "hw/mem/pc-dimm.h"
 #include "qapi/error.h"
 #include "qemu/config-file.h"
 #include "qapi/visitor.h"
 #include "qemu/range.h"
 #include "sysemu/numa.h"
 #include "sysemu/kvm.h"
 #include "trace.h"
 #include "hw/virtio/vhost.h"

 typedef struct pc_dimms_capacity {
      uint64_t size;
      Error    **errp;
 } pc_dimms_capacity;

 void pc_dimm_memory_plug(DeviceState *dev, MemoryHotplugState *hpms,
                          MemoryRegion *mr, uint64_t align, Error **errp)
 {
     int slot;
     MachineState *machine = MACHINE(qdev_get_machine());
     PCDIMMDevice *dimm = PC_DIMM(dev);
     Error *local_err = NULL;
     uint64_t existing_dimms_capacity = 0;
     uint64_t addr;

     addr = object_property_get_int(OBJECT(dimm), PC_DIMM_ADDR_PROP, &local_err);
     if (local_err) {
         goto out;
     }

     addr = pc_dimm_get_free_addr(hpms->base,
                                  memory_region_size(&hpms->mr),
                                  !addr ? NULL : &addr, align,
                                  memory_region_size(mr), &local_err);
     if (local_err) {
         goto out;
     }

     existing_dimms_capacity = pc_existing_dimms_capacity(&local_err);
     if (local_err) {
         goto out;
     }

     if (existing_dimms_capacity + memory_region_size(mr) >
         machine->maxram_size - machine->ram_size) {
         error_setg(&local_err, "not enough space, currently 0x%" PRIx64
                    " in use of total hot pluggable 0x" RAM_ADDR_FMT,
                    existing_dimms_capacity,
                    machine->maxram_size - machine->ram_size);
         goto out;
     }

     object_property_set_int(OBJECT(dev), addr, PC_DIMM_ADDR_PROP, &local_err);
     if (local_err) {
         goto out;
     }
     trace_mhp_pc_dimm_assigned_address(addr);

     slot = object_property_get_int(OBJECT(dev), PC_DIMM_SLOT_PROP, &local_err);
     if (local_err) {
         goto out;
     }

     slot = pc_dimm_get_free_slot(slot == PC_DIMM_UNASSIGNED_SLOT ? NULL : &slot,
                                  machine->ram_slots, &local_err);
     if (local_err) {
         goto out;
     }
     object_property_set_int(OBJECT(dev), slot, PC_DIMM_SLOT_PROP, &local_err);
     if (local_err) {
         goto out;
     }
     trace_mhp_pc_dimm_assigned_slot(slot);

     if (kvm_enabled() && !kvm_has_free_slot(machine)) {
         error_setg(&local_err, "hypervisor has no free memory slots left");
         goto out;
     }

     if (!vhost_has_free_slot()) {
         error_setg(&local_err, "a used vhost backend has no free"
                                " memory slots left");
         goto out;
     }

     memory_region_add_subregion(&hpms->mr, addr - hpms->base, mr);
     vmstate_register_ram(mr, dev);
     numa_set_mem_node_id(addr, memory_region_size(mr), dimm->node);

 out:
     error_propagate(errp, local_err);
 }

 void pc_dimm_memory_unplug(DeviceState *dev, MemoryHotplugState *hpms,
                            MemoryRegion *mr)
 {
     PCDIMMDevice *dimm = PC_DIMM(dev);

     numa_unset_mem_node_id(dimm->addr, memory_region_size(mr), dimm->node);
     memory_region_del_subregion(&hpms->mr, mr);
     vmstate_unregister_ram(mr, dev);
 }

 static int pc_existing_dimms_capacity_internal(Object *obj, void *opaque)
 {
     pc_dimms_capacity *cap = opaque;
     uint64_t *size = &cap->size;

     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
         DeviceState *dev = DEVICE(obj);

         if (dev->realized) {
             (*size) += object_property_get_int(obj, PC_DIMM_SIZE_PROP,
                 cap->errp);
         }

         if (cap->errp && *cap->errp) {
             return 1;
         }
     }
     object_child_foreach(obj, pc_existing_dimms_capacity_internal, opaque);
     return 0;
 }

 uint64_t pc_existing_dimms_capacity(Error **errp)
 {
     pc_dimms_capacity cap;

     cap.size = 0;
     cap.errp = errp;

     pc_existing_dimms_capacity_internal(qdev_get_machine(), &cap);
     return cap.size;
 }

 int qmp_pc_dimm_device_list(Object *obj, void *opaque)
 {
     MemoryDeviceInfoList ***prev = opaque;

     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
         DeviceState *dev = DEVICE(obj);

         if (dev->realized) {
             MemoryDeviceInfoList *elem = g_new0(MemoryDeviceInfoList, 1);
             MemoryDeviceInfo *info = g_new0(MemoryDeviceInfo, 1);
             PCDIMMDeviceInfo *di = g_new0(PCDIMMDeviceInfo, 1);
             DeviceClass *dc = DEVICE_GET_CLASS(obj);
             PCDIMMDevice *dimm = PC_DIMM(obj);

             if (dev->id) {
                 di->has_id = true;
                 di->id = g_strdup(dev->id);
             }
             di->hotplugged = dev->hotplugged;
             di->hotpluggable = dc->hotpluggable;
             di->addr = dimm->addr;
             di->slot = dimm->slot;
             di->node = dimm->node;
             di->size = object_property_get_int(OBJECT(dimm), PC_DIMM_SIZE_PROP,
                                                NULL);
             di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));

             info->u.dimm.data = di;
             elem->value = info;
             elem->next = NULL;
             **prev = elem;
             *prev = &elem->next;
         }
     }

     object_child_foreach(obj, qmp_pc_dimm_device_list, opaque);
     return 0;
 }

 static int pc_dimm_slot2bitmap(Object *obj, void *opaque)
 {
     unsigned long *bitmap = opaque;

     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
         DeviceState *dev = DEVICE(obj);
         if (dev->realized) { /* count only realized DIMMs */
             PCDIMMDevice *d = PC_DIMM(obj);
             set_bit(d->slot, bitmap);
         }
     }

     object_child_foreach(obj, pc_dimm_slot2bitmap, opaque);
     return 0;
 }

 int pc_dimm_get_free_slot(const int *hint, int max_slots, Error **errp)
 {
     unsigned long *bitmap = bitmap_new(max_slots);
     int slot = 0;

     object_child_foreach(qdev_get_machine(), pc_dimm_slot2bitmap, bitmap);

     /* check if requested slot is not occupied */
     if (hint) {
         if (*hint >= max_slots) {
             error_setg(errp, "invalid slot# %d, should be less than %d",
                        *hint, max_slots);
         } else if (!test_bit(*hint, bitmap)) {
             slot = *hint;
         } else {
             error_setg(errp, "slot %d is busy", *hint);
         }
         goto out;
     }

     /* search for free slot */
     slot = find_first_zero_bit(bitmap, max_slots);
     if (slot == max_slots) {
         error_setg(errp, "no free slots available");
     }
 out:
     g_free(bitmap);
     return slot;
 }

 static gint pc_dimm_addr_sort(gconstpointer a, gconstpointer b)
 {
     PCDIMMDevice *x = PC_DIMM(a);
     PCDIMMDevice *y = PC_DIMM(b);
     Int128 diff = int128_sub(int128_make64(x->addr), int128_make64(y->addr));

     if (int128_lt(diff, int128_zero())) {
         return -1;
     } else if (int128_gt(diff, int128_zero())) {
         return 1;
     }
     return 0;
 }

 static int pc_dimm_built_list(Object *obj, void *opaque)
 {
     GSList **list = opaque;

     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
         DeviceState *dev = DEVICE(obj);
         if (dev->realized) { /* only realized DIMMs matter */
             *list = g_slist_insert_sorted(*list, dev, pc_dimm_addr_sort);
         }
     }

     object_child_foreach(obj, pc_dimm_built_list, opaque);
     return 0;
 }

 uint64_t pc_dimm_get_free_addr(uint64_t address_space_start,
                                uint64_t address_space_size,
                                uint64_t *hint, uint64_t align, uint64_t size,
                                Error **errp)
 {
     GSList *list = NULL, *item;
     uint64_t new_addr, ret = 0;
     uint64_t address_space_end = address_space_start + address_space_size;

     g_assert(QEMU_ALIGN_UP(address_space_start, align) == address_space_start);

     if (!address_space_size) {
         error_setg(errp, "memory hotplug is not enabled, "
                          "please add maxmem option");
         goto out;
     }

     if (hint && QEMU_ALIGN_UP(*hint, align) != *hint) {
         error_setg(errp, "address must be aligned to 0x%" PRIx64 " bytes",
                    align);
         goto out;
     }

     if (QEMU_ALIGN_UP(size, align) != size) {
         error_setg(errp, "backend memory size must be multiple of 0x%"
                    PRIx64, align);
         goto out;
     }

     assert(address_space_end > address_space_start);
     object_child_foreach(qdev_get_machine(), pc_dimm_built_list, &list);

     if (hint) {
         new_addr = *hint;
     } else {
         new_addr = address_space_start;
     }

     /* find address range that will fit new DIMM */
     for (item = list; item; item = g_slist_next(item)) {
         PCDIMMDevice *dimm = item->data;
         uint64_t dimm_size = object_property_get_int(OBJECT(dimm),
                                                      PC_DIMM_SIZE_PROP,
                                                      errp);
         if (errp && *errp) {
             goto out;
         }

         if (ranges_overlap(dimm->addr, dimm_size, new_addr, size)) {
             if (hint) {
                 DeviceState *d = DEVICE(dimm);
                 error_setg(errp, "address range conflicts with '%s'", d->id);
                 goto out;
             }
             new_addr = QEMU_ALIGN_UP(dimm->addr + dimm_size, align);
         }
     }
     ret = new_addr;

     if (new_addr < address_space_start) {
         error_setg(errp, "can't add memory [0x%" PRIx64 ":0x%" PRIx64
                    "] at 0x%" PRIx64, new_addr, size, address_space_start);
     } else if ((new_addr + size) > address_space_end) {
         error_setg(errp, "can't add memory [0x%" PRIx64 ":0x%" PRIx64
                    "] beyond 0x%" PRIx64, new_addr, size, address_space_end);
     }

 out:
     g_slist_free(list);
     return ret;
 }

 static Property pc_dimm_properties[] = {
     DEFINE_PROP_UINT64(PC_DIMM_ADDR_PROP, PCDIMMDevice, addr, 0),
     DEFINE_PROP_UINT32(PC_DIMM_NODE_PROP, PCDIMMDevice, node, 0),
     DEFINE_PROP_INT32(PC_DIMM_SLOT_PROP, PCDIMMDevice, slot,
                       PC_DIMM_UNASSIGNED_SLOT),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void pc_dimm_get_size(Object *obj, Visitor *v, const char *name,
                              void *opaque, Error **errp)
 {
     int64_t value;
     MemoryRegion *mr;
     PCDIMMDevice *dimm = PC_DIMM(obj);

     mr = host_memory_backend_get_memory(dimm->hostmem, errp);
     value = memory_region_size(mr);

     visit_type_int(v, name, &value, errp);
 }

 static void pc_dimm_check_memdev_is_busy(Object *obj, const char *name,
                                       Object *val, Error **errp)
 {
     MemoryRegion *mr;
     Error *local_err = NULL;

     mr = host_memory_backend_get_memory(MEMORY_BACKEND(val), &local_err);
     if (local_err) {
         goto out;
     }
     if (memory_region_is_mapped(mr)) {
         char *path = object_get_canonical_path_component(val);
         error_setg(&local_err, "can't use already busy memdev: %s", path);
         g_free(path);
     } else {
         qdev_prop_allow_set_link_before_realize(obj, name, val, &local_err);
     }

 out:
     error_propagate(errp, local_err);
 }

 static void pc_dimm_init(Object *obj)
 {
     PCDIMMDevice *dimm = PC_DIMM(obj);

     object_property_add(obj, PC_DIMM_SIZE_PROP, "int", pc_dimm_get_size,
                         NULL, NULL, NULL, &error_abort);
     object_property_add_link(obj, PC_DIMM_MEMDEV_PROP, TYPE_MEMORY_BACKEND,
                              (Object **)&dimm->hostmem,
                              pc_dimm_check_memdev_is_busy,
                              OBJ_PROP_LINK_UNREF_ON_RELEASE,
                              &error_abort);
 }

 static void pc_dimm_realize(DeviceState *dev, Error **errp)
 {
     PCDIMMDevice *dimm = PC_DIMM(dev);

     if (!dimm->hostmem) {
         error_setg(errp, "'" PC_DIMM_MEMDEV_PROP "' property is not set");
         return;
     }
     if (((nb_numa_nodes > 0) && (dimm->node >= nb_numa_nodes)) ||
         (!nb_numa_nodes && dimm->node)) {
         error_setg(errp, "'DIMM property " PC_DIMM_NODE_PROP " has value %"
                    PRIu32 "' which exceeds the number of numa nodes: %d",
                    dimm->node, nb_numa_nodes ? nb_numa_nodes : 1);
         return;
     }
 }

 static MemoryRegion *pc_dimm_get_memory_region(PCDIMMDevice *dimm)
 {
     return host_memory_backend_get_memory(dimm->hostmem, &error_abort);
 }

 static void pc_dimm_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
     PCDIMMDeviceClass *ddc = PC_DIMM_CLASS(oc);

     dc->realize = pc_dimm_realize;
     dc->props = pc_dimm_properties;
     dc->desc = "DIMM memory module";

     ddc->get_memory_region = pc_dimm_get_memory_region;
 }

 static TypeInfo pc_dimm_info = {
     .name          = TYPE_PC_DIMM,
     .parent        = TYPE_DEVICE,
     .instance_size = sizeof(PCDIMMDevice),
     .instance_init = pc_dimm_init,
     .class_init    = pc_dimm_class_init,
     .class_size    = sizeof(PCDIMMDeviceClass),
 };

 static void pc_dimm_register_types(void)
 {
     type_register_static(&pc_dimm_info);
 }

 type_init(pc_dimm_register_types)
	/*
	* Dimm device for Memory Hotplug
	*
	* Copyright ProfitBricks GmbH 2012
	* Copyright (C) 2014 Red Hat Inc
	*
	* 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 "qemu/osdep.h"
	#include "hw/mem/pc-dimm.h"
	#include "qapi/error.h"
	#include "qemu/config-file.h"
	#include "qapi/visitor.h"
	#include "qemu/range.h"
	#include "sysemu/numa.h"
	#include "sysemu/kvm.h"
	#include "trace.h"
	#include "hw/virtio/vhost.h"

	typedef struct pc_dimms_capacity {
	uint64_t size;
	Error **errp;
	} pc_dimms_capacity;

	void pc_dimm_memory_plug(DeviceState dev, MemoryHotplugState hpms,
	MemoryRegion mr, uint64_t align, Error *errp)
	{
	int slot;
	MachineState *machine = MACHINE(qdev_get_machine());
	PCDIMMDevice *dimm = PC_DIMM(dev);
	Error *local_err = NULL;
	uint64_t existing_dimms_capacity = 0;
	uint64_t addr;

	addr = object_property_get_int(OBJECT(dimm), PC_DIMM_ADDR_PROP, &local_err);
	if (local_err) {
	goto out;
	}

	addr = pc_dimm_get_free_addr(hpms->base,
	memory_region_size(&hpms->mr),
	!addr ? NULL : &addr, align,
	memory_region_size(mr), &local_err);
	if (local_err) {
	goto out;
	}

	existing_dimms_capacity = pc_existing_dimms_capacity(&local_err);
	if (local_err) {
	goto out;
	}

	if (existing_dimms_capacity + memory_region_size(mr) >
	machine->maxram_size - machine->ram_size) {
	error_setg(&local_err, "not enough space, currently 0x%" PRIx64
	" in use of total hot pluggable 0x" RAM_ADDR_FMT,
	existing_dimms_capacity,
	machine->maxram_size - machine->ram_size);
	goto out;
	}

	object_property_set_int(OBJECT(dev), addr, PC_DIMM_ADDR_PROP, &local_err);
	if (local_err) {
	goto out;
	}
	trace_mhp_pc_dimm_assigned_address(addr);

	slot = object_property_get_int(OBJECT(dev), PC_DIMM_SLOT_PROP, &local_err);
	if (local_err) {
	goto out;
	}

	slot = pc_dimm_get_free_slot(slot == PC_DIMM_UNASSIGNED_SLOT ? NULL : &slot,
	machine->ram_slots, &local_err);
	if (local_err) {
	goto out;
	}
	object_property_set_int(OBJECT(dev), slot, PC_DIMM_SLOT_PROP, &local_err);
	if (local_err) {
	goto out;
	}
	trace_mhp_pc_dimm_assigned_slot(slot);

	if (kvm_enabled() && !kvm_has_free_slot(machine)) {
	error_setg(&local_err, "hypervisor has no free memory slots left");
	goto out;
	}

	if (!vhost_has_free_slot()) {
	error_setg(&local_err, "a used vhost backend has no free"
	" memory slots left");
	goto out;
	}

	memory_region_add_subregion(&hpms->mr, addr - hpms->base, mr);
	vmstate_register_ram(mr, dev);
	numa_set_mem_node_id(addr, memory_region_size(mr), dimm->node);

	out:
	error_propagate(errp, local_err);
	}

	void pc_dimm_memory_unplug(DeviceState dev, MemoryHotplugState hpms,
	MemoryRegion *mr)
	{
	PCDIMMDevice *dimm = PC_DIMM(dev);

	numa_unset_mem_node_id(dimm->addr, memory_region_size(mr), dimm->node);
	memory_region_del_subregion(&hpms->mr, mr);
	vmstate_unregister_ram(mr, dev);
	}

	static int pc_existing_dimms_capacity_internal(Object obj, void opaque)
	{
	pc_dimms_capacity *cap = opaque;
	uint64_t *size = &cap->size;

	if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
	DeviceState *dev = DEVICE(obj);

	if (dev->realized) {
	(*size) += object_property_get_int(obj, PC_DIMM_SIZE_PROP,
	cap->errp);
	}

	if (cap->errp && *cap->errp) {
	return 1;
	}
	}
	object_child_foreach(obj, pc_existing_dimms_capacity_internal, opaque);
	return 0;
	}

	uint64_t pc_existing_dimms_capacity(Error **errp)
	{
	pc_dimms_capacity cap;

	cap.size = 0;
	cap.errp = errp;

	pc_existing_dimms_capacity_internal(qdev_get_machine(), &cap);
	return cap.size;
	}

	int qmp_pc_dimm_device_list(Object obj, void opaque)
	{
	MemoryDeviceInfoList ***prev = opaque;

	if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
	DeviceState *dev = DEVICE(obj);

	if (dev->realized) {
	MemoryDeviceInfoList *elem = g_new0(MemoryDeviceInfoList, 1);
	MemoryDeviceInfo *info = g_new0(MemoryDeviceInfo, 1);
	PCDIMMDeviceInfo *di = g_new0(PCDIMMDeviceInfo, 1);
	DeviceClass *dc = DEVICE_GET_CLASS(obj);
	PCDIMMDevice *dimm = PC_DIMM(obj);

	if (dev->id) {
	di->has_id = true;
	di->id = g_strdup(dev->id);
	}
	di->hotplugged = dev->hotplugged;
	di->hotpluggable = dc->hotpluggable;
	di->addr = dimm->addr;
	di->slot = dimm->slot;
	di->node = dimm->node;
	di->size = object_property_get_int(OBJECT(dimm), PC_DIMM_SIZE_PROP,
	NULL);
	di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));

	info->u.dimm.data = di;
	elem->value = info;
	elem->next = NULL;
	**prev = elem;
	*prev = &elem->next;
	}
	}

	object_child_foreach(obj, qmp_pc_dimm_device_list, opaque);
	return 0;
	}

	static int pc_dimm_slot2bitmap(Object obj, void opaque)
	{
	unsigned long *bitmap = opaque;

	if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
	DeviceState *dev = DEVICE(obj);
	if (dev->realized) { /* count only realized DIMMs */
	PCDIMMDevice *d = PC_DIMM(obj);
	set_bit(d->slot, bitmap);
	}
	}

	object_child_foreach(obj, pc_dimm_slot2bitmap, opaque);
	return 0;
	}

	int pc_dimm_get_free_slot(const int hint, int max_slots, Error *errp)
	{
	unsigned long *bitmap = bitmap_new(max_slots);
	int slot = 0;

	object_child_foreach(qdev_get_machine(), pc_dimm_slot2bitmap, bitmap);

	/* check if requested slot is not occupied */
	if (hint) {
	if (*hint >= max_slots) {
	error_setg(errp, "invalid slot# %d, should be less than %d",
	*hint, max_slots);
	} else if (!test_bit(*hint, bitmap)) {
	slot = *hint;
	} else {
	error_setg(errp, "slot %d is busy", *hint);
	}
	goto out;
	}

	/* search for free slot */
	slot = find_first_zero_bit(bitmap, max_slots);
	if (slot == max_slots) {
	error_setg(errp, "no free slots available");
	}
	out:
	g_free(bitmap);
	return slot;
	}

	static gint pc_dimm_addr_sort(gconstpointer a, gconstpointer b)
	{
	PCDIMMDevice *x = PC_DIMM(a);
	PCDIMMDevice *y = PC_DIMM(b);
	Int128 diff = int128_sub(int128_make64(x->addr), int128_make64(y->addr));

	if (int128_lt(diff, int128_zero())) {
	return -1;
	} else if (int128_gt(diff, int128_zero())) {
	return 1;
	}
	return 0;
	}

	static int pc_dimm_built_list(Object obj, void opaque)
	{
	GSList **list = opaque;

	if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
	DeviceState *dev = DEVICE(obj);
	if (dev->realized) { /* only realized DIMMs matter */
	list = g_slist_insert_sorted(list, dev, pc_dimm_addr_sort);
	}
	}

	object_child_foreach(obj, pc_dimm_built_list, opaque);
	return 0;
	}

	uint64_t pc_dimm_get_free_addr(uint64_t address_space_start,
	uint64_t address_space_size,
	uint64_t *hint, uint64_t align, uint64_t size,
	Error **errp)
	{
	GSList list = NULL, item;
	uint64_t new_addr, ret = 0;
	uint64_t address_space_end = address_space_start + address_space_size;

	g_assert(QEMU_ALIGN_UP(address_space_start, align) == address_space_start);

	if (!address_space_size) {
	error_setg(errp, "memory hotplug is not enabled, "
	"please add maxmem option");
	goto out;
	}

	if (hint && QEMU_ALIGN_UP(hint, align) != hint) {
	error_setg(errp, "address must be aligned to 0x%" PRIx64 " bytes",
	align);
	goto out;
	}

	if (QEMU_ALIGN_UP(size, align) != size) {
	error_setg(errp, "backend memory size must be multiple of 0x%"
	PRIx64, align);
	goto out;
	}

	assert(address_space_end > address_space_start);
	object_child_foreach(qdev_get_machine(), pc_dimm_built_list, &list);

	if (hint) {
	new_addr = *hint;
	} else {
	new_addr = address_space_start;
	}

	/* find address range that will fit new DIMM */
	for (item = list; item; item = g_slist_next(item)) {
	PCDIMMDevice *dimm = item->data;
	uint64_t dimm_size = object_property_get_int(OBJECT(dimm),
	PC_DIMM_SIZE_PROP,
	errp);
	if (errp && *errp) {
	goto out;
	}

	if (ranges_overlap(dimm->addr, dimm_size, new_addr, size)) {
	if (hint) {
	DeviceState *d = DEVICE(dimm);
	error_setg(errp, "address range conflicts with '%s'", d->id);
	goto out;
	}
	new_addr = QEMU_ALIGN_UP(dimm->addr + dimm_size, align);
	}
	}
	ret = new_addr;

	if (new_addr < address_space_start) {
	error_setg(errp, "can't add memory [0x%" PRIx64 ":0x%" PRIx64
	"] at 0x%" PRIx64, new_addr, size, address_space_start);
	} else if ((new_addr + size) > address_space_end) {
	error_setg(errp, "can't add memory [0x%" PRIx64 ":0x%" PRIx64
	"] beyond 0x%" PRIx64, new_addr, size, address_space_end);
	}

	out:
	g_slist_free(list);
	return ret;
	}

	static Property pc_dimm_properties[] = {
	DEFINE_PROP_UINT64(PC_DIMM_ADDR_PROP, PCDIMMDevice, addr, 0),
	DEFINE_PROP_UINT32(PC_DIMM_NODE_PROP, PCDIMMDevice, node, 0),
	DEFINE_PROP_INT32(PC_DIMM_SLOT_PROP, PCDIMMDevice, slot,
	PC_DIMM_UNASSIGNED_SLOT),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void pc_dimm_get_size(Object obj, Visitor v, const char *name,
	void opaque, Error *errp)
	{
	int64_t value;
	MemoryRegion *mr;
	PCDIMMDevice *dimm = PC_DIMM(obj);

	mr = host_memory_backend_get_memory(dimm->hostmem, errp);
	value = memory_region_size(mr);

	visit_type_int(v, name, &value, errp);
	}

	static void pc_dimm_check_memdev_is_busy(Object obj, const char name,
	Object val, Error *errp)
	{
	MemoryRegion *mr;
	Error *local_err = NULL;

	mr = host_memory_backend_get_memory(MEMORY_BACKEND(val), &local_err);
	if (local_err) {
	goto out;
	}
	if (memory_region_is_mapped(mr)) {
	char *path = object_get_canonical_path_component(val);
	error_setg(&local_err, "can't use already busy memdev: %s", path);
	g_free(path);
	} else {
	qdev_prop_allow_set_link_before_realize(obj, name, val, &local_err);
	}

	out:
	error_propagate(errp, local_err);
	}

	static void pc_dimm_init(Object *obj)
	{
	PCDIMMDevice *dimm = PC_DIMM(obj);

	object_property_add(obj, PC_DIMM_SIZE_PROP, "int", pc_dimm_get_size,
	NULL, NULL, NULL, &error_abort);
	object_property_add_link(obj, PC_DIMM_MEMDEV_PROP, TYPE_MEMORY_BACKEND,
	(Object **)&dimm->hostmem,
	pc_dimm_check_memdev_is_busy,
	OBJ_PROP_LINK_UNREF_ON_RELEASE,
	&error_abort);
	}

	static void pc_dimm_realize(DeviceState dev, Error *errp)
	{
	PCDIMMDevice *dimm = PC_DIMM(dev);

	if (!dimm->hostmem) {
	error_setg(errp, "'" PC_DIMM_MEMDEV_PROP "' property is not set");
	return;
	}
	if (((nb_numa_nodes > 0) && (dimm->node >= nb_numa_nodes)) \|\|
	(!nb_numa_nodes && dimm->node)) {
	error_setg(errp, "'DIMM property " PC_DIMM_NODE_PROP " has value %"
	PRIu32 "' which exceeds the number of numa nodes: %d",
	dimm->node, nb_numa_nodes ? nb_numa_nodes : 1);
	return;
	}
	}

	static MemoryRegion pc_dimm_get_memory_region(PCDIMMDevice dimm)
	{
	return host_memory_backend_get_memory(dimm->hostmem, &error_abort);
	}

	static void pc_dimm_class_init(ObjectClass oc, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(oc);
	PCDIMMDeviceClass *ddc = PC_DIMM_CLASS(oc);

	dc->realize = pc_dimm_realize;
	dc->props = pc_dimm_properties;
	dc->desc = "DIMM memory module";

	ddc->get_memory_region = pc_dimm_get_memory_region;
	}

	static TypeInfo pc_dimm_info = {
	.name = TYPE_PC_DIMM,
	.parent = TYPE_DEVICE,
	.instance_size = sizeof(PCDIMMDevice),
	.instance_init = pc_dimm_init,
	.class_init = pc_dimm_class_init,
	.class_size = sizeof(PCDIMMDeviceClass),
	};

	static void pc_dimm_register_types(void)
	{
	type_register_static(&pc_dimm_info);
	}

	type_init(pc_dimm_register_types)