diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index ecfee362a1..acf9bfbece 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2546,10 +2546,17 @@ static void machvirt_machine_init(void)
 }
 type_init(machvirt_machine_init);
 
-static void virt_machine_5_1_options(MachineClass *mc)
+static void virt_machine_5_2_options(MachineClass *mc)
 {
 }
-DEFINE_VIRT_MACHINE_AS_LATEST(5, 1)
+DEFINE_VIRT_MACHINE_AS_LATEST(5, 2)
+
+static void virt_machine_5_1_options(MachineClass *mc)
+{
+    virt_machine_5_2_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
+}
+DEFINE_VIRT_MACHINE(5, 1)
 
 static void virt_machine_5_0_options(MachineClass *mc)
 {
diff --git a/hw/core/machine-qmp-cmds.c b/hw/core/machine-qmp-cmds.c
index 963088b798..21551221ad 100644
--- a/hw/core/machine-qmp-cmds.c
+++ b/hw/core/machine-qmp-cmds.c
@@ -238,6 +238,10 @@ MachineInfoList *qmp_query_machines(Error **errp)
             info->default_cpu_type = g_strdup(mc->default_cpu_type);
             info->has_default_cpu_type = true;
         }
+        if (mc->default_ram_id) {
+            info->default_ram_id = g_strdup(mc->default_ram_id);
+            info->has_default_ram_id = true;
+        }
 
         entry = g_malloc0(sizeof(*entry));
         entry->value = info;
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 8d1a90c6cf..cf5f2dfaeb 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -28,6 +28,9 @@
 #include "hw/mem/nvdimm.h"
 #include "migration/vmstate.h"
 
+GlobalProperty hw_compat_5_1[] = {};
+const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
+
 GlobalProperty hw_compat_5_0[] = {
     { "pci-host-bridge", "x-config-reg-migration-enabled", "off" },
     { "virtio-balloon-device", "page-poison", "false" },
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index cc616e48f3..5d8d5ef8b3 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -97,6 +97,9 @@
 #include "trace.h"
 #include CONFIG_DEVICES
 
+GlobalProperty pc_compat_5_1[] = {};
+const size_t pc_compat_5_1_len = G_N_ELEMENTS(pc_compat_5_1);
+
 GlobalProperty pc_compat_5_0[] = {
 };
 const size_t pc_compat_5_0_len = G_N_ELEMENTS(pc_compat_5_0);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 456e336934..32b1453e6a 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -426,7 +426,7 @@ static void pc_i440fx_machine_options(MachineClass *m)
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE);
 }
 
-static void pc_i440fx_5_1_machine_options(MachineClass *m)
+static void pc_i440fx_5_2_machine_options(MachineClass *m)
 {
     PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_i440fx_machine_options(m);
@@ -435,6 +435,18 @@ static void pc_i440fx_5_1_machine_options(MachineClass *m)
     pcmc->default_cpu_version = 1;
 }
 
+DEFINE_I440FX_MACHINE(v5_2, "pc-i440fx-5.2", NULL,
+                      pc_i440fx_5_2_machine_options);
+
+static void pc_i440fx_5_1_machine_options(MachineClass *m)
+{
+    pc_i440fx_5_2_machine_options(m);
+    m->alias = NULL;
+    m->is_default = false;
+    compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
+    compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
+}
+
 DEFINE_I440FX_MACHINE(v5_1, "pc-i440fx-5.1", NULL,
                       pc_i440fx_5_1_machine_options);
 
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index a3e607a544..0cb9c18cd4 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -353,7 +353,7 @@ static void pc_q35_machine_options(MachineClass *m)
     m->max_cpus = 288;
 }
 
-static void pc_q35_5_1_machine_options(MachineClass *m)
+static void pc_q35_5_2_machine_options(MachineClass *m)
 {
     PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_machine_options(m);
@@ -361,6 +361,17 @@ static void pc_q35_5_1_machine_options(MachineClass *m)
     pcmc->default_cpu_version = 1;
 }
 
+DEFINE_Q35_MACHINE(v5_2, "pc-q35-5.2", NULL,
+                   pc_q35_5_2_machine_options);
+
+static void pc_q35_5_1_machine_options(MachineClass *m)
+{
+    pc_q35_5_2_machine_options(m);
+    m->alias = NULL;
+    compat_props_add(m->compat_props, hw_compat_5_1, hw_compat_5_1_len);
+    compat_props_add(m->compat_props, pc_compat_5_1, pc_compat_5_1_len);
+}
+
 DEFINE_Q35_MACHINE(v5_1, "pc-q35-5.1", NULL,
                    pc_q35_5_1_machine_options);
 
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 0ae293ec94..1c8d0981b3 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4580,14 +4580,25 @@ static void spapr_machine_latest_class_options(MachineClass *mc)
     type_init(spapr_machine_register_##suffix)
 
 /*
- * pseries-5.1
+ * pseries-5.2
  */
-static void spapr_machine_5_1_class_options(MachineClass *mc)
+static void spapr_machine_5_2_class_options(MachineClass *mc)
 {
     /* Defaults for the latest behaviour inherited from the base class */
 }
 
-DEFINE_SPAPR_MACHINE(5_1, "5.1", true);
+DEFINE_SPAPR_MACHINE(5_2, "5.2", true);
+
+/*
+ * pseries-5.1
+ */
+static void spapr_machine_5_1_class_options(MachineClass *mc)
+{
+    spapr_machine_5_2_class_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
+}
+
+DEFINE_SPAPR_MACHINE(5_1, "5.1", false);
 
 /*
  * pseries-5.0
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index e72c61d2ea..f4ea6a9545 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -801,14 +801,26 @@ bool css_migration_enabled(void)
     }                                                                         \
     type_init(ccw_machine_register_##suffix)
 
+static void ccw_machine_5_2_instance_options(MachineState *machine)
+{
+}
+
+static void ccw_machine_5_2_class_options(MachineClass *mc)
+{
+}
+DEFINE_CCW_MACHINE(5_2, "5.2", true);
+
 static void ccw_machine_5_1_instance_options(MachineState *machine)
 {
+    ccw_machine_5_2_instance_options(machine);
 }
 
 static void ccw_machine_5_1_class_options(MachineClass *mc)
 {
+    ccw_machine_5_2_class_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_5_1, hw_compat_5_1_len);
 }
-DEFINE_CCW_MACHINE(5_1, "5.1", true);
+DEFINE_CCW_MACHINE(5_1, "5.1", false);
 
 static void ccw_machine_5_0_instance_options(MachineState *machine)
 {
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 426ce5f625..bc5b82ad20 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -319,6 +319,9 @@ struct MachineState {
     } \
     type_init(machine_initfn##_register_types)
 
+extern GlobalProperty hw_compat_5_1[];
+extern const size_t hw_compat_5_1_len;
+
 extern GlobalProperty hw_compat_5_0[];
 extern const size_t hw_compat_5_0_len;
 
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 3d7ed3a55e..fe52e165b2 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -193,6 +193,9 @@ void pc_system_firmware_init(PCMachineState *pcms, MemoryRegion *rom_memory);
 void pc_madt_cpu_entry(AcpiDeviceIf *adev, int uid,
                        const CPUArchIdList *apic_ids, GArray *entry);
 
+extern GlobalProperty pc_compat_5_1[];
+extern const size_t pc_compat_5_1_len;
+
 extern GlobalProperty pc_compat_5_0[];
 extern const size_t pc_compat_5_0_len;
 
diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
index 8f3a98cba6..528310bb22 100644
--- a/include/hw/qdev-properties.h
+++ b/include/hw/qdev-properties.h
@@ -238,6 +238,8 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
 
 /*
  * Set properties between creation and realization.
+ *
+ * Returns: %true on success, %false on error.
  */
 bool qdev_prop_set_drive_err(DeviceState *dev, const char *name,
                              BlockBackend *value, Error **errp);
diff --git a/qapi/machine.json b/qapi/machine.json
index 481b1f07ec..abc6fd0477 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -357,13 +357,16 @@
 # @default-cpu-type: default CPU model typename if none is requested via
 #                    the -cpu argument. (since 4.2)
 #
+# @default-ram-id: the default ID of initial RAM memory backend (since 5.2)
+#
 # Since: 1.2.0
 ##
 { 'struct': 'MachineInfo',
   'data': { 'name': 'str', '*alias': 'str',
             '*is-default': 'bool', 'cpu-max': 'int',
             'hotpluggable-cpus': 'bool',  'numa-mem-supported': 'bool',
-            'deprecated': 'bool', '*default-cpu-type': 'str' } }
+            'deprecated': 'bool', '*default-cpu-type': 'str',
+            '*default-ram-id': 'str' } }
 
 ##
 # @query-machines: