Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20160311' into staging

CPU hotplug via cpu-add for s390x, cleanup of the s390x machine
compat code and a bugfix in the s390-ccw bios.

# gpg: Signature made Fri 11 Mar 2016 09:48:02 GMT using RSA key ID C6F02FAF
# gpg: Good signature from "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"

* remotes/cohuck/tags/s390x-20160311:
  s390x/cpu: use g_new0
  s390x: Introduce S390MachineClass
  s390x: Introduce machine definition macros
  pc-bios/s390-ccw: fix old bug in ptr increment
  s390x/cpu: Allow hotplug of CPUs
  s390x/cpu: Add error handling to cpu creation
  s390x/cpu: Add CPU property links
  s390x/cpu: Tolerate max_cpus
  s390x/cpu: Get rid of side effects when creating a vcpu
  s390x/cpu: Set initial CPU state in common routine
  s390x/cpu: Cleanup init in preparation for hotplug

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

9 files changed, 289 insertions, 83 deletions

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 89f5d0d6a6..3d8c3c4fa8 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -22,20 +22,7 @@
 #include "s390-pci-bus.h"
 #include "hw/s390x/storage-keys.h"
 #include "hw/compat.h"
-
-#define TYPE_S390_CCW_MACHINE               "s390-ccw-machine"
-
-#define S390_CCW_MACHINE(obj) \
-    OBJECT_CHECK(S390CcwMachineState, (obj), TYPE_S390_CCW_MACHINE)
-
-typedef struct S390CcwMachineState {
-    /*< private >*/
-    MachineState parent_obj;
-
-    /*< public >*/
-    bool aes_key_wrap;
-    bool dea_key_wrap;
-} S390CcwMachineState;
+#include "hw/s390x/s390-virtio-ccw.h"
 
 static const char *const reset_dev_types[] = {
     "virtual-css-bridge",
@@ -136,7 +123,7 @@ static void ccw_init(MachineState *machine)
     virtio_ccw_register_hcalls();
 
     /* init CPUs */
-    s390_init_cpus(machine->cpu_model);
+    s390_init_cpus(machine);
 
     if (kvm_enabled()) {
         kvm_s390_enable_css_support(s390_cpu_addr2state(0));
@@ -156,13 +143,54 @@ static void ccw_init(MachineState *machine)
                     gtod_save, gtod_load, kvm_state);
 }
 
+static void s390_cpu_plug(HotplugHandler *hotplug_dev,
+                        DeviceState *dev, Error **errp)
+{
+    gchar *name;
+    S390CPU *cpu = S390_CPU(dev);
+    CPUState *cs = CPU(dev);
+
+    name = g_strdup_printf("cpu[%i]", cpu->env.cpu_num);
+    object_property_set_link(OBJECT(hotplug_dev), OBJECT(cs), name,
+                             errp);
+    g_free(name);
+}
+
+static void s390_machine_device_plug(HotplugHandler *hotplug_dev,
+                                     DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        s390_cpu_plug(hotplug_dev, dev, errp);
+    }
+}
+
+static HotplugHandler *s390_get_hotplug_handler(MachineState *machine,
+                                                DeviceState *dev)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        return HOTPLUG_HANDLER(machine);
+    }
+    return NULL;
+}
+
+static void s390_hot_add_cpu(const int64_t id, Error **errp)
+{
+    MachineState *machine = MACHINE(qdev_get_machine());
+    Error *err = NULL;
+
+    s390x_new_cpu(machine->cpu_model, id, &err);
+    error_propagate(errp, err);
+}
+
 static void ccw_machine_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
     NMIClass *nc = NMI_CLASS(oc);
+    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
 
     mc->init = ccw_init;
     mc->reset = s390_machine_reset;
+    mc->hot_add_cpu = s390_hot_add_cpu;
     mc->block_default_type = IF_VIRTIO;
     mc->no_cdrom = 1;
     mc->no_floppy = 1;
@@ -171,6 +199,8 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data)
     mc->no_sdcard = 1;
     mc->use_sclp = 1;
     mc->max_cpus = 255;
+    mc->get_hotplug_handler = s390_get_hotplug_handler;
+    hc->plug = s390_machine_device_plug;
     nc->nmi_monitor_handler = s390_nmi;
 }
 
@@ -232,10 +262,40 @@ static const TypeInfo ccw_machine_info = {
     .class_init    = ccw_machine_class_init,
     .interfaces = (InterfaceInfo[]) {
         { TYPE_NMI },
+        { TYPE_HOTPLUG_HANDLER},
         { }
     },
 };
 
+#define DEFINE_CCW_MACHINE(suffix, verstr, latest)                            \
+    static void ccw_machine_##suffix##_class_init(ObjectClass *oc,            \
+                                                  void *data)                 \
+    {                                                                         \
+        MachineClass *mc = MACHINE_CLASS(oc);                                 \
+        ccw_machine_##suffix##_class_options(mc);                             \
+        mc->desc = "VirtIO-ccw based S390 machine v" verstr;                  \
+        if (latest) {                                                         \
+            mc->alias = "s390-ccw-virtio";                                    \
+            mc->is_default = 1;                                               \
+        }                                                                     \
+    }                                                                         \
+    static void ccw_machine_##suffix##_instance_init(Object *obj)             \
+    {                                                                         \
+        MachineState *machine = MACHINE(obj);                                 \
+        ccw_machine_##suffix##_instance_options(machine);                     \
+    }                                                                         \
+    static const TypeInfo ccw_machine_##suffix##_info = {                     \
+        .name = MACHINE_TYPE_NAME("s390-ccw-virtio-" verstr),                 \
+        .parent = TYPE_S390_CCW_MACHINE,                                      \
+        .class_init = ccw_machine_##suffix##_class_init,                      \
+        .instance_init = ccw_machine_##suffix##_instance_init,                \
+    };                                                                        \
+    static void ccw_machine_register_##suffix(void)                           \
+    {                                                                         \
+        type_register_static(&ccw_machine_##suffix##_info);                   \
+    }                                                                         \
+    machine_init(ccw_machine_register_##suffix)
+
 #define CCW_COMPAT_2_5 \
         HW_COMPAT_2_5
 
@@ -280,63 +340,39 @@ static const TypeInfo ccw_machine_info = {
             .value    = "0",\
         },
 
-static void ccw_machine_2_4_class_init(ObjectClass *oc, void *data)
+static void ccw_machine_2_6_instance_options(MachineState *machine)
 {
-    MachineClass *mc = MACHINE_CLASS(oc);
-    static GlobalProperty compat_props[] = {
-        CCW_COMPAT_2_4
-        { /* end of list */ }
-    };
-
-    mc->desc = "VirtIO-ccw based S390 machine v2.4";
-    mc->compat_props = compat_props;
 }
 
-static const TypeInfo ccw_machine_2_4_info = {
-    .name          = MACHINE_TYPE_NAME("s390-ccw-virtio-2.4"),
-    .parent        = TYPE_S390_CCW_MACHINE,
-    .class_init    = ccw_machine_2_4_class_init,
-};
-
-static void ccw_machine_2_5_class_init(ObjectClass *oc, void *data)
+static void ccw_machine_2_6_class_options(MachineClass *mc)
 {
-    MachineClass *mc = MACHINE_CLASS(oc);
-    static GlobalProperty compat_props[] = {
-        CCW_COMPAT_2_5
-        { /* end of list */ }
-    };
-
-    mc->desc = "VirtIO-ccw based S390 machine v2.5";
-    mc->compat_props = compat_props;
 }
+DEFINE_CCW_MACHINE(2_6, "2.6", true);
 
-static const TypeInfo ccw_machine_2_5_info = {
-    .name          = MACHINE_TYPE_NAME("s390-ccw-virtio-2.5"),
-    .parent        = TYPE_S390_CCW_MACHINE,
-    .class_init    = ccw_machine_2_5_class_init,
-};
+static void ccw_machine_2_5_instance_options(MachineState *machine)
+{
+}
 
-static void ccw_machine_2_6_class_init(ObjectClass *oc, void *data)
+static void ccw_machine_2_5_class_options(MachineClass *mc)
 {
-    MachineClass *mc = MACHINE_CLASS(oc);
+    SET_MACHINE_COMPAT(mc, CCW_COMPAT_2_5);
+}
+DEFINE_CCW_MACHINE(2_5, "2.5", false);
 
-    mc->alias = "s390-ccw-virtio";
-    mc->desc = "VirtIO-ccw based S390 machine v2.6";
-    mc->is_default = 1;
+static void ccw_machine_2_4_instance_options(MachineState *machine)
+{
+    ccw_machine_2_5_instance_options(machine);
 }
 
-static const TypeInfo ccw_machine_2_6_info = {
-    .name          = MACHINE_TYPE_NAME("s390-ccw-virtio-2.6"),
-    .parent        = TYPE_S390_CCW_MACHINE,
-    .class_init    = ccw_machine_2_6_class_init,
-};
+static void ccw_machine_2_4_class_options(MachineClass *mc)
+{
+    SET_MACHINE_COMPAT(mc, CCW_COMPAT_2_4);
+}
+DEFINE_CCW_MACHINE(2_4, "2.4", false);
 
 static void ccw_machine_register_types(void)
 {
     type_register_static(&ccw_machine_info);
-    type_register_static(&ccw_machine_2_4_info);
-    type_register_static(&ccw_machine_2_5_info);
-    type_register_static(&ccw_machine_2_6_info);
 }
 
 type_init(ccw_machine_register_types)
diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
index 8e533ae88a..7c6e281af1 100644
--- a/hw/s390x/s390-virtio.c
+++ b/hw/s390x/s390-virtio.c
@@ -58,15 +58,16 @@
 #define S390_TOD_CLOCK_VALUE_MISSING    0x00
 #define S390_TOD_CLOCK_VALUE_PRESENT    0x01
 
-static S390CPU **ipi_states;
+static S390CPU **cpu_states;
 
 S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
 {
-    if (cpu_addr >= smp_cpus) {
+    if (cpu_addr >= max_cpus) {
         return NULL;
     }
 
-    return ipi_states[cpu_addr];
+    /* Fast lookup via CPU ID */
+    return cpu_states[cpu_addr];
 }
 
 void s390_init_ipl_dev(const char *kernel_filename,
@@ -93,26 +94,29 @@ void s390_init_ipl_dev(const char *kernel_filename,
     qdev_init_nofail(dev);
 }
 
-void s390_init_cpus(const char *cpu_model)
+void s390_init_cpus(MachineState *machine)
 {
     int i;
+    gchar *name;
 
-    if (cpu_model == NULL) {
-        cpu_model = "host";
+    if (machine->cpu_model == NULL) {
+        machine->cpu_model = "host";
     }
 
-    ipi_states = g_malloc(sizeof(S390CPU *) * smp_cpus);
+    cpu_states = g_new0(S390CPU *, max_cpus);
 
-    for (i = 0; i < smp_cpus; i++) {
-        S390CPU *cpu;
-        CPUState *cs;
-
-        cpu = cpu_s390x_init(cpu_model);
-        cs = CPU(cpu);
+    for (i = 0; i < max_cpus; i++) {
+        name = g_strdup_printf("cpu[%i]", i);
+        object_property_add_link(OBJECT(machine), name, TYPE_S390_CPU,
+                                 (Object **) &cpu_states[i],
+                                 object_property_allow_set_link,
+                                 OBJ_PROP_LINK_UNREF_ON_RELEASE,
+                                 &error_abort);
+        g_free(name);
+    }
 
-        ipi_states[i] = cpu;
-        cs->halted = 1;
-        cs->exception_index = EXCP_HLT;
+    for (i = 0; i < smp_cpus; i++) {
+        s390x_new_cpu(machine->cpu_model, i, &error_fatal);
     }
 }
 
diff --git a/hw/s390x/s390-virtio.h b/hw/s390x/s390-virtio.h
index eebce8e5e6..ffd014cb5b 100644
--- a/hw/s390x/s390-virtio.h
+++ b/hw/s390x/s390-virtio.h
@@ -19,7 +19,7 @@
 typedef int (*s390_virtio_fn)(const uint64_t *args);
 void s390_register_virtio_hypercall(uint64_t code, s390_virtio_fn fn);
 
-void s390_init_cpus(const char *cpu_model);
+void s390_init_cpus(MachineState *machine);
 void s390_init_ipl_dev(const char *kernel_filename,
                        const char *kernel_cmdline,
                        const char *initrd_filename,
diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
new file mode 100644
index 0000000000..ab08332fe1
--- /dev/null
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -0,0 +1,40 @@
+/*
+ * virtio ccw machine definitions
+ *
+ * Copyright 2012, 2016 IBM Corp.
+ * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+#ifndef HW_S390X_S390_VIRTIO_CCW_H
+#define HW_S390X_S390_VIRTIO_CCW_H
+
+#include "hw/boards.h"
+
+#define TYPE_S390_CCW_MACHINE               "s390-ccw-machine"
+
+#define S390_CCW_MACHINE(obj) \
+    OBJECT_CHECK(S390CcwMachineState, (obj), TYPE_S390_CCW_MACHINE)
+
+#define S390_MACHINE_CLASS(klass) \
+    OBJECT_CLASS_CHECK(S390CcwMachineClass, (klass), TYPE_S390_CCW_MACHINE)
+
+typedef struct S390CcwMachineState {
+    /*< private >*/
+    MachineState parent_obj;
+
+    /*< public >*/
+    bool aes_key_wrap;
+    bool dea_key_wrap;
+} S390CcwMachineState;
+
+typedef struct S390CcwMachineClass {
+    /*< private >*/
+    MachineClass parent_class;
+
+    /*< public >*/
+} S390CcwMachineClass;
+
+#endif
diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index 415508b279..492530275d 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -424,7 +424,7 @@ static void ipl_scsi(void)
     IPL_assert(magic_match(sec, ZIPL_MAGIC), "No zIPL magic");
 
     ns_end = sec + virtio_get_block_size();
-    for (ns = (sec + pte_len); (ns + pte_len) < ns_end; ns++) {
+    for (ns = (sec + pte_len); (ns + pte_len) < ns_end; ns += pte_len) {
         prog_table_entry = (ScsiBlockPtr *)ns;
         if (!prog_table_entry->blockno) {
             break;
diff --git a/target-s390x/cpu-qom.h b/target-s390x/cpu-qom.h
index 029a44af24..1c90933965 100644
--- a/target-s390x/cpu-qom.h
+++ b/target-s390x/cpu-qom.h
@@ -47,6 +47,8 @@ typedef struct S390CPUClass {
     CPUClass parent_class;
     /*< public >*/
 
+    int64_t next_cpu_id;
+
     DeviceRealize parent_realize;
     void (*parent_reset)(CPUState *cpu);
     void (*load_normal)(CPUState *cpu);
@@ -66,6 +68,7 @@ typedef struct S390CPU {
     /*< public >*/
 
     CPUS390XState env;
+    int64_t id;
     /* needed for live migration */
     void *irqstate;
     uint32_t irqstate_saved_size;
diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index 73a910d2fa..1cbf70355d 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -30,8 +30,11 @@
 #include "qemu/error-report.h"
 #include "hw/hw.h"
 #include "trace.h"
+#include "qapi/visitor.h"
 #ifndef CONFIG_USER_ONLY
 #include "sysemu/arch_init.h"
+#include "sysemu/sysemu.h"
+#include "hw/s390x/sclp.h"
 #endif
 
 #define CR0_RESET       0xE0UL
@@ -195,7 +198,39 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
 {
     CPUState *cs = CPU(dev);
     S390CPUClass *scc = S390_CPU_GET_CLASS(dev);
+    S390CPU *cpu = S390_CPU(dev);
+    CPUS390XState *env = &cpu->env;
+    Error *err = NULL;
+
+#if !defined(CONFIG_USER_ONLY)
+    if (cpu->id >= max_cpus) {
+        error_setg(&err, "Unable to add CPU: %" PRIi64
+                   ", max allowed: %d", cpu->id, max_cpus - 1);
+        goto out;
+    }
+#endif
+    if (cpu_exists(cpu->id)) {
+        error_setg(&err, "Unable to add CPU: %" PRIi64
+                   ", it already exists", cpu->id);
+        goto out;
+    }
+    if (cpu->id != scc->next_cpu_id) {
+        error_setg(&err, "Unable to add CPU: %" PRIi64
+                   ", The next available id is %" PRIi64, cpu->id,
+                   scc->next_cpu_id);
+        goto out;
+    }
+
+    cpu_exec_init(cs, &err);
+    if (err != NULL) {
+        goto out;
+    }
+    scc->next_cpu_id++;
 
+#if !defined(CONFIG_USER_ONLY)
+    qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
+#endif
+    env->cpu_num = cpu->id;
     s390_cpu_gdb_init(cs);
     qemu_init_vcpu(cs);
 #if !defined(CONFIG_USER_ONLY)
@@ -204,7 +239,55 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
     cpu_reset(cs);
 #endif
 
-    scc->parent_realize(dev, errp);
+    scc->parent_realize(dev, &err);
+
+#if !defined(CONFIG_USER_ONLY)
+    if (dev->hotplugged) {
+        raise_irq_cpu_hotplug();
+    }
+#endif
+
+out:
+    error_propagate(errp, err);
+}
+
+static void s390x_cpu_get_id(Object *obj, Visitor *v, const char *name,
+                             void *opaque, Error **errp)
+{
+    S390CPU *cpu = S390_CPU(obj);
+    int64_t value = cpu->id;
+
+    visit_type_int(v, name, &value, errp);
+}
+
+static void s390x_cpu_set_id(Object *obj, Visitor *v, const char *name,
+                             void *opaque, Error **errp)
+{
+    S390CPU *cpu = S390_CPU(obj);
+    DeviceState *dev = DEVICE(obj);
+    const int64_t min = 0;
+    const int64_t max = UINT32_MAX;
+    Error *err = NULL;
+    int64_t value;
+
+    if (dev->realized) {
+        error_setg(errp, "Attempt to set property '%s' on '%s' after "
+                   "it was realized", name, object_get_typename(obj));
+        return;
+    }
+
+    visit_type_int(v, name, &value, &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+    if (value < min || value > max) {
+        error_setg(errp, "Property %s.%s doesn't take value %" PRId64
+                   " (minimum: %" PRId64 ", maximum: %" PRId64 ")" ,
+                   object_get_typename(obj), name, value, min, max);
+        return;
+    }
+    cpu->id = value;
 }
 
 static void s390_cpu_initfn(Object *obj)
@@ -213,15 +296,16 @@ static void s390_cpu_initfn(Object *obj)
     S390CPU *cpu = S390_CPU(obj);
     CPUS390XState *env = &cpu->env;
     static bool inited;
-    static int cpu_num = 0;
 #if !defined(CONFIG_USER_ONLY)
     struct tm tm;
 #endif
 
     cs->env_ptr = env;
-    cpu_exec_init(cs, &error_abort);
+    cs->halted = 1;
+    cs->exception_index = EXCP_HLT;
+    object_property_add(OBJECT(cpu), "id", "int64_t", s390x_cpu_get_id,
+                        s390x_cpu_set_id, NULL, NULL, NULL);
 #if !defined(CONFIG_USER_ONLY)
-    qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
     qemu_get_timedate(&tm, 0);
     env->tod_offset = TOD_UNIX_EPOCH +
                       (time2tod(mktimegm(&tm)) * 1000000000ULL);
@@ -230,7 +314,6 @@ static void s390_cpu_initfn(Object *obj)
     env->cpu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, s390x_cpu_timer, cpu);
     s390_cpu_set_state(CPU_STATE_STOPPED, cpu);
 #endif
-    env->cpu_num = cpu_num++;
 
     if (tcg_enabled() && !inited) {
         inited = true;
@@ -337,6 +420,7 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     CPUClass *cc = CPU_CLASS(scc);
     DeviceClass *dc = DEVICE_CLASS(oc);
 
+    scc->next_cpu_id = 0;
     scc->parent_realize = dc->realize;
     dc->realize = s390_cpu_realizefn;
 
@@ -369,7 +453,7 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     cc->gdb_arch_name = s390_gdb_arch_name;
 
     /*
-     * Reason: s390_cpu_initfn() calls cpu_exec_init(), which saves
+     * Reason: s390_cpu_realizefn() calls cpu_exec_init(), which saves
      * the object in cpus -> dangling pointer after final
      * object_unref().
      */
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 49c84155be..6d97c089a4 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -413,6 +413,8 @@ void trigger_pgm_exception(CPUS390XState *env, uint32_t code, uint32_t ilen);
 #endif
 
 S390CPU *cpu_s390x_init(const char *cpu_model);
+S390CPU *s390x_new_cpu(const char *cpu_model, int64_t id, Error **errp);
+S390CPU *cpu_s390x_create(const char *cpu_model, Error **errp);
 void s390x_translate_init(void);
 int cpu_s390x_exec(CPUState *cpu);
 
diff --git a/target-s390x/helper.c b/target-s390x/helper.c
index 838bdd9e9e..76d5fbebe8 100644
--- a/target-s390x/helper.c
+++ b/target-s390x/helper.c
@@ -65,14 +65,51 @@ void s390x_cpu_timer(void *opaque)
 }
 #endif
 
-S390CPU *cpu_s390x_init(const char *cpu_model)
+S390CPU *cpu_s390x_create(const char *cpu_model, Error **errp)
 {
     S390CPU *cpu;
 
     cpu = S390_CPU(object_new(TYPE_S390_CPU));
 
-    object_property_set_bool(OBJECT(cpu), true, "realized", NULL);
+    return cpu;
+}
+
+S390CPU *s390x_new_cpu(const char *cpu_model, int64_t id, Error **errp)
+{
+    S390CPU *cpu;
+    Error *err = NULL;
+
+    cpu = cpu_s390x_create(cpu_model, &err);
+    if (err != NULL) {
+        goto out;
+    }
+
+    object_property_set_int(OBJECT(cpu), id, "id", &err);
+    if (err != NULL) {
+        goto out;
+    }
+    object_property_set_bool(OBJECT(cpu), true, "realized", &err);
 
+out:
+    if (err) {
+        error_propagate(errp, err);
+        object_unref(OBJECT(cpu));
+        cpu = NULL;
+    }
+    return cpu;
+}
+
+S390CPU *cpu_s390x_init(const char *cpu_model)
+{
+    Error *err = NULL;
+    S390CPU *cpu;
+    /* Use to track CPU ID for linux-user only */
+    static int64_t next_cpu_id;
+
+    cpu = s390x_new_cpu(cpu_model, next_cpu_id++, &err);
+    if (err) {
+        error_report_err(err);
+    }
     return cpu;
 }