diff --git a/bindings/dotnet/Unicorn/Const/Common.fs b/bindings/dotnet/Unicorn/Const/Common.fs
index 2133de54..c3c4655e 100644
--- a/bindings/dotnet/Unicorn/Const/Common.fs
+++ b/bindings/dotnet/Unicorn/Const/Common.fs
@@ -58,6 +58,7 @@ module Common =
    let UC_ERR_WRITE_UNALIGNED = 17
    let UC_ERR_FETCH_UNALIGNED = 18
    let UC_ERR_HOOK_EXIST = 19
+   let UC_ERR_RESOURCE = 20
    let UC_MEM_READ = 16
    let UC_MEM_WRITE = 17
    let UC_MEM_FETCH = 18
diff --git a/bindings/go/unicorn/unicorn_const.go b/bindings/go/unicorn/unicorn_const.go
index 2f80dea3..38ba0c8b 100644
--- a/bindings/go/unicorn/unicorn_const.go
+++ b/bindings/go/unicorn/unicorn_const.go
@@ -53,6 +53,7 @@ const (
 	ERR_WRITE_UNALIGNED = 17
 	ERR_FETCH_UNALIGNED = 18
 	ERR_HOOK_EXIST = 19
+	ERR_RESOURCE = 20
 	MEM_READ = 16
 	MEM_WRITE = 17
 	MEM_FETCH = 18
diff --git a/bindings/java/unicorn/UnicornConst.java b/bindings/java/unicorn/UnicornConst.java
index 6139ecf5..2bd8eabe 100644
--- a/bindings/java/unicorn/UnicornConst.java
+++ b/bindings/java/unicorn/UnicornConst.java
@@ -55,6 +55,7 @@ public interface UnicornConst {
    public static final int UC_ERR_WRITE_UNALIGNED = 17;
    public static final int UC_ERR_FETCH_UNALIGNED = 18;
    public static final int UC_ERR_HOOK_EXIST = 19;
+   public static final int UC_ERR_RESOURCE = 20;
    public static final int UC_MEM_READ = 16;
    public static final int UC_MEM_WRITE = 17;
    public static final int UC_MEM_FETCH = 18;
diff --git a/bindings/python/unicorn/unicorn_const.py b/bindings/python/unicorn/unicorn_const.py
index 48162807..01cde40c 100644
--- a/bindings/python/unicorn/unicorn_const.py
+++ b/bindings/python/unicorn/unicorn_const.py
@@ -51,6 +51,7 @@ UC_ERR_READ_UNALIGNED = 16
 UC_ERR_WRITE_UNALIGNED = 17
 UC_ERR_FETCH_UNALIGNED = 18
 UC_ERR_HOOK_EXIST = 19
+UC_ERR_RESOURCE = 20
 UC_MEM_READ = 16
 UC_MEM_WRITE = 17
 UC_MEM_FETCH = 18
diff --git a/include/uc_priv.h b/include/uc_priv.h
index f1f7ec2e..1493a7fd 100644
--- a/include/uc_priv.h
+++ b/include/uc_priv.h
@@ -36,6 +36,7 @@ typedef bool (*uc_read_mem_t)(AddressSpace *as, hwaddr addr, uint8_t *buf, int l
 typedef void (*uc_args_void_t)(void*);
 
 typedef void (*uc_args_uc_t)(struct uc_struct*);
+typedef int (*uc_args_int_uc_t)(struct uc_struct*);
 
 typedef bool (*uc_args_tcg_enable_t)(struct uc_struct*);
 
@@ -91,7 +92,8 @@ struct uc_struct {
     uc_args_uc_u64_t set_pc;  // set PC for tracecode
     uc_args_int_t stop_interrupt;   // check if the interrupt should stop emulation
 
-    uc_args_uc_t init_arch, pause_all_vcpus, vm_start, cpu_exec_init_all;
+    uc_args_uc_t init_arch, pause_all_vcpus, cpu_exec_init_all;
+    uc_args_int_uc_t vm_start;
     uc_args_tcg_enable_t tcg_enabled;
     uc_args_uc_long_t tcg_exec_init;
     uc_args_uc_ram_size_t memory_map;
diff --git a/include/unicorn/unicorn.h b/include/unicorn/unicorn.h
index b812b473..a7a13b60 100644
--- a/include/unicorn/unicorn.h
+++ b/include/unicorn/unicorn.h
@@ -125,6 +125,7 @@ typedef enum uc_err {
     UC_ERR_WRITE_UNALIGNED,  // Unaligned write
     UC_ERR_FETCH_UNALIGNED,  // Unaligned fetch
     UC_ERR_HOOK_EXIST,  // hook for this event already existed
+    UC_ERR_RESOURCE,    // Insufficient resource: uc_emu_start()
 } uc_err;
 
 
diff --git a/qemu/cpus.c b/qemu/cpus.c
index e274fe5a..98ee07c1 100644
--- a/qemu/cpus.c
+++ b/qemu/cpus.c
@@ -37,16 +37,19 @@ static bool cpu_can_run(CPUState *cpu);
 static void cpu_handle_guest_debug(CPUState *cpu);
 static int tcg_cpu_exec(struct uc_struct *uc, CPUArchState *env);
 static bool tcg_exec_all(struct uc_struct* uc);
-static void qemu_tcg_init_vcpu(CPUState *cpu);
+static int qemu_tcg_init_vcpu(CPUState *cpu);
 static void *qemu_tcg_cpu_thread_fn(void *arg);
 
-void vm_start(struct uc_struct* uc)
+int vm_start(struct uc_struct* uc)
 {
-    resume_all_vcpus(uc);
+    if (resume_all_vcpus(uc)) {
+        return -1;
+    }
 
-    //sleep(3);
     // kick off TCG thread
     qemu_mutex_unlock_iothread(uc);
+
+    return 0;
 }
 
 bool cpu_is_stopped(CPUState *cpu)
@@ -78,7 +81,7 @@ void pause_all_vcpus(struct uc_struct *uc)
 }
 
 
-void resume_all_vcpus(struct uc_struct *uc)
+int resume_all_vcpus(struct uc_struct *uc)
 {
     CPUState *cpu;
 
@@ -93,7 +96,8 @@ void resume_all_vcpus(struct uc_struct *uc)
             CPU_FOREACH(cpu) {
                 cpu->created = true;
                 cpu->halted = 0;
-                qemu_init_vcpu(cpu);
+                if (qemu_init_vcpu(cpu))
+                    return -1;
             }
             qemu_mutex_lock_iothread(uc);
         }
@@ -103,18 +107,21 @@ void resume_all_vcpus(struct uc_struct *uc)
     CPU_FOREACH(cpu) {
         cpu_resume(cpu);
     }
+
+    return 0;
 }
 
-void qemu_init_vcpu(CPUState *cpu)
+int qemu_init_vcpu(CPUState *cpu)
 {
     cpu->nr_cores = smp_cores;
     cpu->nr_threads = smp_threads;
     cpu->stopped = true;
     cpu->uc->tcg_cpu_thread = NULL;
 
-    if (tcg_enabled(cpu->uc)) {
-        qemu_tcg_init_vcpu(cpu);
-    }
+    if (tcg_enabled(cpu->uc))
+        return qemu_tcg_init_vcpu(cpu);
+
+    return 0;
 }
 
 
@@ -133,7 +140,6 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
     }
     qemu_cond_signal(&uc->qemu_cpu_cond);
 
-
    /* wait for initial kick-off after machine start */
     while (QTAILQ_FIRST(&uc->cpus)->stopped) {
         qemu_cond_wait(uc->tcg_halt_cond, &uc->qemu_global_mutex);
@@ -170,7 +176,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
 /* For temporary buffers for forming a name */
 #define VCPU_THREAD_NAME_SIZE 16
 
-static void qemu_tcg_init_vcpu(CPUState *cpu)
+static int qemu_tcg_init_vcpu(CPUState *cpu)
 {
     struct uc_struct *uc = cpu->uc;
     char thread_name[VCPU_THREAD_NAME_SIZE];
@@ -185,8 +191,9 @@ static void qemu_tcg_init_vcpu(CPUState *cpu)
         uc->tcg_halt_cond = cpu->halt_cond;
         snprintf(thread_name, VCPU_THREAD_NAME_SIZE, "CPU %d/TCG",
                 cpu->cpu_index);
-        qemu_thread_create(uc, cpu->thread, thread_name, qemu_tcg_cpu_thread_fn,
-                cpu, QEMU_THREAD_JOINABLE);
+        if (qemu_thread_create(uc, cpu->thread, thread_name, qemu_tcg_cpu_thread_fn,
+                cpu, QEMU_THREAD_JOINABLE))
+            return -1;
 #ifdef _WIN32
         cpu->hThread = qemu_thread_get_handle(cpu->thread);
 #endif
@@ -198,6 +205,8 @@ static void qemu_tcg_init_vcpu(CPUState *cpu)
         cpu->thread = uc->tcg_cpu_thread;
         cpu->halt_cond = uc->tcg_halt_cond;
     }
+
+    return 0;
 }
 
 static int tcg_cpu_exec(struct uc_struct *uc, CPUArchState *env)
diff --git a/qemu/hw/arm/tosa.c b/qemu/hw/arm/tosa.c
index 818fe32f..fe9eaf6e 100644
--- a/qemu/hw/arm/tosa.c
+++ b/qemu/hw/arm/tosa.c
@@ -17,10 +17,12 @@
 #include "exec/address-spaces.h"
 
 
-static void tosa_init(struct uc_struct *uc, MachineState *machine)
+static int tosa_init(struct uc_struct *uc, MachineState *machine)
 {
     //cpu_arm_init(uc, "pxa255");
     cpu_arm_init(uc, "cortex-a15"); // FIXME
+
+    return 0;
 }
 
 void tosa_machine_init(struct uc_struct *uc)
diff --git a/qemu/hw/arm/virt.c b/qemu/hw/arm/virt.c
index b9156317..554e89d7 100644
--- a/qemu/hw/arm/virt.c
+++ b/qemu/hw/arm/virt.c
@@ -36,7 +36,7 @@
 #include "exec/address-spaces.h"
 
 
-static void machvirt_init(struct uc_struct *uc, MachineState *machine)
+static int machvirt_init(struct uc_struct *uc, MachineState *machine)
 {
     const char *cpu_model = machine->cpu_model;
     int n;
@@ -51,12 +51,14 @@ static void machvirt_init(struct uc_struct *uc, MachineState *machine)
 
         if (!oc) {
             fprintf(stderr, "Unable to find CPU definition\n");
-            exit(1);
+            return -1;
         }
 
         cpuobj = object_new(uc, object_class_get_name(oc));
         object_property_set_bool(uc, cpuobj, true, "realized", NULL);
     }
+
+    return 0;
 }
 
 void machvirt_machine_init(struct uc_struct *uc)
diff --git a/qemu/hw/core/qdev.c b/qemu/hw/core/qdev.c
index e3340895..14e3ccec 100644
--- a/qemu/hw/core/qdev.c
+++ b/qemu/hw/core/qdev.c
@@ -155,7 +155,7 @@ static bool device_get_realized(struct uc_struct *uc, Object *obj, Error **errp)
     return dev->realized;
 }
 
-static void device_set_realized(struct uc_struct *uc, Object *obj, bool value, Error **errp)
+static int device_set_realized(struct uc_struct *uc, Object *obj, bool value, Error **errp)
 {
     DeviceState *dev = DEVICE(uc, obj);
     DeviceClass *dc = DEVICE_GET_CLASS(uc, dev);
@@ -164,7 +164,7 @@ static void device_set_realized(struct uc_struct *uc, Object *obj, bool value, E
 
     if (dev->hotplugged && !dc->hotpluggable) {
         error_set(errp, QERR_DEVICE_NO_HOTPLUG, object_get_typename(obj));
-        return;
+        return -1;
     }
 
     if (value && !dev->realized) {
@@ -181,7 +181,8 @@ static void device_set_realized(struct uc_struct *uc, Object *obj, bool value, E
 #endif
 
         if (dc->realize) {
-            dc->realize(uc, dev, &local_err);
+            if (dc->realize(uc, dev, &local_err))
+                return -1;
         }
 
         if (local_err != NULL) {
@@ -222,7 +223,7 @@ static void device_set_realized(struct uc_struct *uc, Object *obj, bool value, E
     }
 
     dev->realized = value;
-    return;
+    return 0;
 
 child_realize_fail:
     QLIST_FOREACH(bus, &dev->child_bus, sibling) {
@@ -237,7 +238,7 @@ post_realize_fail:
 
 fail:
     error_propagate(errp, local_err);
-    return;
+    return -1;
 }
 
 static void device_initfn(struct uc_struct *uc, Object *obj, void *opaque)
diff --git a/qemu/hw/i386/pc.c b/qemu/hw/i386/pc.c
index 5f201dbc..0721fba1 100644
--- a/qemu/hw/i386/pc.c
+++ b/qemu/hw/i386/pc.c
@@ -104,7 +104,7 @@ static X86CPU *pc_new_cpu(struct uc_struct *uc, const char *cpu_model, int64_t a
     }
 
     object_property_set_int(uc, OBJECT(cpu), apic_id, "apic-id", &local_err);
-    object_property_set_bool(uc, OBJECT(cpu), true, "realized", &local_err);
+    object_property_set_bool(uc, OBJECT(cpu), true, "realized", &local_err);    // qq
 
     if (local_err) {
         error_propagate(errp, local_err);
@@ -114,7 +114,7 @@ static X86CPU *pc_new_cpu(struct uc_struct *uc, const char *cpu_model, int64_t a
     return cpu;
 }
 
-void pc_cpus_init(struct uc_struct *uc, const char *cpu_model)
+int pc_cpus_init(struct uc_struct *uc, const char *cpu_model)
 {
     int i;
     Error *error = NULL;
@@ -129,13 +129,15 @@ void pc_cpus_init(struct uc_struct *uc, const char *cpu_model)
     }
 
     for (i = 0; i < smp_cpus; i++) {
-        uc->cpu = pc_new_cpu(uc, cpu_model, x86_cpu_apic_id_from_index(i), &error);
+        uc->cpu = pc_new_cpu(uc, cpu_model, x86_cpu_apic_id_from_index(i), &error); // qq
         if (error) {
             //error_report("%s", error_get_pretty(error));
             error_free(error);
-            exit(1);
+            return -1;
         }
     }
+
+    return 0;
 }
 
 static void pc_machine_initfn(struct uc_struct *uc, Object *obj, void *opaque)
diff --git a/qemu/hw/i386/pc_piix.c b/qemu/hw/i386/pc_piix.c
index 41f06ee3..b9759621 100644
--- a/qemu/hw/i386/pc_piix.c
+++ b/qemu/hw/i386/pc_piix.c
@@ -36,14 +36,14 @@
 #define GIGABYTE_ALIGN true
 
 /* PC hardware initialisation */
-static void pc_init1(struct uc_struct *uc, MachineState *machine)
+static int pc_init1(struct uc_struct *uc, MachineState *machine)
 {
-    pc_cpus_init(uc, machine->cpu_model);
+    return pc_cpus_init(uc, machine->cpu_model);
 }
 
-static void pc_init_pci(struct uc_struct *uc, MachineState *machine)
+static int pc_init_pci(struct uc_struct *uc, MachineState *machine)
 {
-    pc_init1(uc, machine);
+    return pc_init1(uc, machine);
 }
 
 #define PC_I440FX_MACHINE_OPTIONS \
diff --git a/qemu/hw/intc/apic.c b/qemu/hw/intc/apic.c
index 0cd0ab68..e58d742b 100644
--- a/qemu/hw/intc/apic.c
+++ b/qemu/hw/intc/apic.c
@@ -186,8 +186,9 @@ static void apic_post_load(APICCommonState *s)
     }
 }
 
-static void apic_realize(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int apic_realize(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
+    return 0;
 }
 
 static void apic_class_init(struct uc_struct *uc, ObjectClass *klass, void *data)
diff --git a/qemu/hw/intc/apic_common.c b/qemu/hw/intc/apic_common.c
index d8f9cda6..c5d32e39 100644
--- a/qemu/hw/intc/apic_common.c
+++ b/qemu/hw/intc/apic_common.c
@@ -196,7 +196,7 @@ static void apic_reset_common(struct uc_struct *uc, DeviceState *dev)
     }
 }
 
-static void apic_common_realize(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int apic_common_realize(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     APICCommonState *s = APIC_COMMON(uc, dev);
     APICCommonClass *info;
@@ -204,7 +204,7 @@ static void apic_common_realize(struct uc_struct *uc, DeviceState *dev, Error **
     if (uc->apic_no >= MAX_APICS) {
         error_setg(errp, "%s initialization failed.",
                    object_get_typename(OBJECT(dev)));
-        return;
+        return -1;
     }
     s->idx = uc->apic_no++;
 
@@ -225,6 +225,8 @@ static void apic_common_realize(struct uc_struct *uc, DeviceState *dev, Error **
     if (uc->apic_report_tpr_access && info->enable_tpr_reporting) {
         info->enable_tpr_reporting(s, true);
     }
+
+    return 0;
 }
 
 static void apic_common_class_init(struct uc_struct *uc, ObjectClass *klass, void *data)
diff --git a/qemu/hw/m68k/dummy_m68k.c b/qemu/hw/m68k/dummy_m68k.c
index 735e820c..5fd6ecb0 100644
--- a/qemu/hw/m68k/dummy_m68k.c
+++ b/qemu/hw/m68k/dummy_m68k.c
@@ -16,7 +16,7 @@
 
 
 /* Board init.  */
-static void dummy_m68k_init(struct uc_struct *uc, MachineState *machine)
+static int dummy_m68k_init(struct uc_struct *uc, MachineState *machine)
 {
     const char *cpu_model = machine->cpu_model;
     CPUM68KState *env;
@@ -27,12 +27,14 @@ static void dummy_m68k_init(struct uc_struct *uc, MachineState *machine)
     env = cpu_init(uc, cpu_model);
     if (!env) {
         fprintf(stderr, "Unable to find m68k CPU definition\n");
-        exit(1);
+        return -1;
     }
 
     /* Initialize CPU registers.  */
     env->vbr = 0;
     env->pc = 0;
+
+    return 0;
 }
 
 void dummy_m68k_machine_init(struct uc_struct *uc)
diff --git a/qemu/hw/mips/mips_r4k.c b/qemu/hw/mips/mips_r4k.c
index 739d8029..0482567c 100644
--- a/qemu/hw/mips/mips_r4k.c
+++ b/qemu/hw/mips/mips_r4k.c
@@ -20,7 +20,7 @@
 #include "exec/address-spaces.h"
 
 
-static void mips_r4k_init(struct uc_struct *uc, MachineState *machine)
+static int mips_r4k_init(struct uc_struct *uc, MachineState *machine)
 {
     const char *cpu_model = machine->cpu_model;
     MIPSCPU *cpu;
@@ -38,8 +38,10 @@ static void mips_r4k_init(struct uc_struct *uc, MachineState *machine)
     cpu = cpu_mips_init(uc, cpu_model);
     if (cpu == NULL) {
         fprintf(stderr, "Unable to find CPU definition\n");
-        exit(1);
+        return -1;
     }
+
+    return 0;
 }
 
 void mips_machine_init(struct uc_struct *uc)
diff --git a/qemu/hw/sparc/leon3.c b/qemu/hw/sparc/leon3.c
index 48c04576..07a4296c 100644
--- a/qemu/hw/sparc/leon3.c
+++ b/qemu/hw/sparc/leon3.c
@@ -33,7 +33,7 @@
 #include "exec/address-spaces.h"
 
 
-static void leon3_generic_hw_init(struct uc_struct *uc, MachineState *machine)
+static int leon3_generic_hw_init(struct uc_struct *uc, MachineState *machine)
 {
     const char *cpu_model = machine->cpu_model;
     SPARCCPU *cpu;
@@ -46,10 +46,12 @@ static void leon3_generic_hw_init(struct uc_struct *uc, MachineState *machine)
     cpu = cpu_sparc_init(uc, cpu_model);
     if (cpu == NULL) {
         fprintf(stderr, "qemu: Unable to find Sparc CPU definition\n");
-        exit(1);
+        return -1;
     }
 
     cpu_sparc_set_id(&cpu->env, 0);
+
+    return 0;
 }
 
 void leon3_machine_init(struct uc_struct *uc)
diff --git a/qemu/hw/sparc64/sun4u.c b/qemu/hw/sparc64/sun4u.c
index 7377a023..7e85a4a4 100644
--- a/qemu/hw/sparc64/sun4u.c
+++ b/qemu/hw/sparc64/sun4u.c
@@ -30,7 +30,7 @@
 
 
 /* Sun4u hardware initialisation */
-static void sun4u_init(struct uc_struct *uc, MachineState *machine)
+static int sun4u_init(struct uc_struct *uc, MachineState *machine)
 {
     const char *cpu_model = machine->cpu_model;
     SPARCCPU *cpu;
@@ -41,8 +41,10 @@ static void sun4u_init(struct uc_struct *uc, MachineState *machine)
     cpu = cpu_sparc_init(uc, cpu_model);
     if (cpu == NULL) {
         fprintf(stderr, "Unable to find Sparc CPU definition\n");
-        exit(1);
+        return -1;
     }
+
+    return 0;
 }
 
 void sun4u_machine_init(struct uc_struct *uc)
diff --git a/qemu/include/hw/boards.h b/qemu/include/hw/boards.h
index b18d75ad..e0afde01 100644
--- a/qemu/include/hw/boards.h
+++ b/qemu/include/hw/boards.h
@@ -9,7 +9,7 @@
 #include "qom/object.h"
 #include "uc_priv.h"
 
-typedef void QEMUMachineInitFunc(struct uc_struct *uc, MachineState *ms);
+typedef int QEMUMachineInitFunc(struct uc_struct *uc, MachineState *ms);
 
 typedef void QEMUMachineResetFunc(void);
 
@@ -54,7 +54,7 @@ struct MachineClass {
     const char *family; /* NULL iff @name identifies a standalone machtype */
     const char *name;
 
-    void (*init)(struct uc_struct *uc, MachineState *state);
+    int (*init)(struct uc_struct *uc, MachineState *state);
     void (*reset)(void);
 
     int max_cpus;
diff --git a/qemu/include/hw/i386/pc.h b/qemu/include/hw/i386/pc.h
index c5478641..c149ed7a 100644
--- a/qemu/include/hw/i386/pc.h
+++ b/qemu/include/hw/i386/pc.h
@@ -34,7 +34,7 @@ typedef struct PCMachineClass PCMachineClass;
 #define PC_MACHINE_CLASS(klass) \
     OBJECT_CLASS_CHECK(PCMachineClass, (klass), TYPE_PC_MACHINE)
 
-void pc_cpus_init(struct uc_struct *uc, const char *cpu_model);
+int pc_cpus_init(struct uc_struct *uc, const char *cpu_model);
 
 FWCfgState *pc_memory_init(MachineState *machine,
                            MemoryRegion *system_memory,
diff --git a/qemu/include/hw/qdev-core.h b/qemu/include/hw/qdev-core.h
index c735dfe0..bfaf773b 100644
--- a/qemu/include/hw/qdev-core.h
+++ b/qemu/include/hw/qdev-core.h
@@ -32,7 +32,7 @@ typedef enum DeviceCategory {
 typedef int (*qdev_initfn)(DeviceState *dev);
 typedef int (*qdev_event)(DeviceState *dev);
 typedef void (*qdev_resetfn)(DeviceState *dev);
-typedef void (*DeviceRealize)(struct uc_struct *uc, DeviceState *dev, Error **errp);
+typedef int (*DeviceRealize)(struct uc_struct *uc, DeviceState *dev, Error **errp);
 typedef void (*DeviceUnrealize)(DeviceState *dev, Error **errp);
 typedef void (*BusRealize)(BusState *bus, Error **errp);
 typedef void (*BusUnrealize)(BusState *bus, Error **errp);
diff --git a/qemu/include/qemu/thread.h b/qemu/include/qemu/thread.h
index de5956b2..2a402673 100644
--- a/qemu/include/qemu/thread.h
+++ b/qemu/include/qemu/thread.h
@@ -53,7 +53,8 @@ void qemu_event_wait(QemuEvent *ev);
 void qemu_event_destroy(QemuEvent *ev);
 
 struct uc_struct;
-void qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *name,
+// return -1 on error, 0 on success
+int qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *name,
                         void *(*start_routine)(void *),
                         void *arg, int mode);
 void *qemu_thread_join(QemuThread *thread);
diff --git a/qemu/include/qom/cpu.h b/qemu/include/qom/cpu.h
index 4e293c21..fb666d1e 100644
--- a/qemu/include/qom/cpu.h
+++ b/qemu/include/qom/cpu.h
@@ -582,7 +582,7 @@ void cpu_resume(CPUState *cpu);
  *
  * Initializes a vCPU.
  */
-void qemu_init_vcpu(CPUState *cpu);
+int qemu_init_vcpu(CPUState *cpu);
 
 #define SSTEP_ENABLE  0x1  /* Enable simulated HW single stepping */
 #define SSTEP_NOIRQ   0x2  /* Do not use IRQ while single stepping */
diff --git a/qemu/include/qom/object.h b/qemu/include/qom/object.h
index 8e097cf7..001e6236 100644
--- a/qemu/include/qom/object.h
+++ b/qemu/include/qom/object.h
@@ -304,6 +304,11 @@ typedef void (ObjectPropertyAccessor)(struct uc_struct *uc, Object *obj,
                                       void *opaque,
                                       const char *name,
                                       Error **errp);
+typedef int (ObjectPropertySetAccessor)(struct uc_struct *uc, Object *obj,
+                                      struct Visitor *v,
+                                      void *opaque,
+                                      const char *name,
+                                      Error **errp);
 
 /**
  * ObjectPropertyResolve:
@@ -342,7 +347,7 @@ typedef struct ObjectProperty
     gchar *type;
     gchar *description;
     ObjectPropertyAccessor *get;
-    ObjectPropertyAccessor *set;
+    ObjectPropertySetAccessor *set;
     ObjectPropertyResolve *resolve;
     ObjectPropertyRelease *release;
     void *opaque;
@@ -799,7 +804,7 @@ void object_unref(struct uc_struct *uc, Object *obj);
 ObjectProperty *object_property_add(Object *obj, const char *name,
                                     const char *type,
                                     ObjectPropertyAccessor *get,
-                                    ObjectPropertyAccessor *set,
+                                    ObjectPropertySetAccessor *set,
                                     ObjectPropertyRelease *release,
                                     void *opaque, Error **errp);
 
@@ -1168,7 +1173,7 @@ void object_property_add_link(Object *obj, const char *name,
  */
 void object_property_add_str(Object *obj, const char *name,
                              char *(*get)(struct uc_struct *uc, Object *, Error **),
-                             void (*set)(struct uc_struct *uc, Object *, const char *, Error **),
+                             int (*set)(struct uc_struct *uc, Object *, const char *, Error **),
                              Error **errp);
 
 /**
@@ -1184,7 +1189,7 @@ void object_property_add_str(Object *obj, const char *name,
  */
 void object_property_add_bool(struct uc_struct *uc, Object *obj, const char *name,
                               bool (*get)(struct uc_struct *uc, Object *, Error **),
-                              void (*set)(struct uc_struct *uc, Object *, bool, Error **),
+                              int (*set)(struct uc_struct *uc, Object *, bool, Error **),
                               Error **errp);
 
 /**
diff --git a/qemu/include/sysemu/cpus.h b/qemu/include/sysemu/cpus.h
index 80843a65..f22ad69d 100644
--- a/qemu/include/sysemu/cpus.h
+++ b/qemu/include/sysemu/cpus.h
@@ -5,7 +5,7 @@ struct uc_struct;
 
 /* cpus.c */
 void qemu_init_cpu_loop(struct uc_struct*);
-void resume_all_vcpus(struct uc_struct*);
+int resume_all_vcpus(struct uc_struct*);
 void pause_all_vcpus(struct uc_struct*);
 void cpu_stop_current(struct uc_struct*);
 
diff --git a/qemu/include/sysemu/sysemu.h b/qemu/include/sysemu/sysemu.h
index 3e08b527..f2ab6e95 100644
--- a/qemu/include/sysemu/sysemu.h
+++ b/qemu/include/sysemu/sysemu.h
@@ -17,7 +17,7 @@ typedef struct vm_change_state_entry VMChangeStateEntry;
 #define VMRESET_SILENT   false
 #define VMRESET_REPORT   true
 
-void vm_start(struct uc_struct*);
+int vm_start(struct uc_struct*);
 
 void qemu_system_reset_request(struct uc_struct*);
 void qemu_system_shutdown_request(void);
diff --git a/qemu/qom/cpu.c b/qemu/qom/cpu.c
index c98535ca..d01d5f5c 100644
--- a/qemu/qom/cpu.c
+++ b/qemu/qom/cpu.c
@@ -216,13 +216,15 @@ static void cpu_common_parse_features(CPUState *cpu, char *features,
     }
 }
 
-static void cpu_common_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int cpu_common_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     CPUState *cpu = CPU(dev);
 
     if (dev->hotplugged) {
         cpu_resume(cpu);
     }
+
+    return 0;
 }
 
 static void cpu_common_initfn(struct uc_struct *uc, Object *obj, void *opaque)
diff --git a/qemu/qom/object.c b/qemu/qom/object.c
index ab6b4882..aca451ba 100644
--- a/qemu/qom/object.c
+++ b/qemu/qom/object.c
@@ -716,7 +716,7 @@ void object_unref(struct uc_struct *uc, Object *obj)
 ObjectProperty *
 object_property_add(Object *obj, const char *name, const char *type,
                     ObjectPropertyAccessor *get,
-                    ObjectPropertyAccessor *set,
+                    ObjectPropertySetAccessor *set,
                     ObjectPropertyRelease *release,
                     void *opaque, Error **errp)
 {
@@ -826,7 +826,8 @@ void object_property_set(struct uc_struct *uc, Object *obj, Visitor *v, const ch
     if (!prop->set) {
         error_set(errp, QERR_PERMISSION_DENIED);
     } else {
-        prop->set(uc, obj, v, prop->opaque, name, errp);
+        if (prop->set(uc, obj, v, prop->opaque, name, errp))
+            error_set(errp, QERR_UNDEFINED_ERROR);
     }
 }
 
@@ -1169,7 +1170,7 @@ static Object *object_resolve_link(struct uc_struct *uc, Object *obj, const char
     return target;
 }
 
-static void object_set_link_property(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int object_set_link_property(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                                      const char *name, Error **errp)
 {
     Error *local_err = NULL;
@@ -1188,18 +1189,20 @@ static void object_set_link_property(struct uc_struct *uc, Object *obj, Visitor
     g_free(path);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
 
     prop->check(obj, name, new_target, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
 
     object_ref(new_target);
     *child = new_target;
     object_unref(uc, old_target);
+
+    return 0;
 }
 
 static Object *object_resolve_link_property(struct uc_struct *uc, Object *parent, void *opaque, const gchar *part)
@@ -1410,7 +1413,7 @@ Object *object_resolve_path(struct uc_struct *uc, const char *path, bool *ambigu
 typedef struct StringProperty
 {
     char *(*get)(struct uc_struct *uc, Object *, Error **);
-    void (*set)(struct uc_struct *uc, Object *, const char *, Error **);
+    int (*set)(struct uc_struct *uc, Object *, const char *, Error **);
 } StringProperty;
 
 static void property_get_str(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
@@ -1426,7 +1429,7 @@ static void property_get_str(struct uc_struct *uc, Object *obj, Visitor *v, void
     }
 }
 
-static void property_set_str(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int property_set_str(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                              const char *name, Error **errp)
 {
     StringProperty *prop = opaque;
@@ -1436,11 +1439,13 @@ static void property_set_str(struct uc_struct *uc, Object *obj, Visitor *v, void
     visit_type_str(v, &value, name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
 
     prop->set(uc, obj, value, errp);
     g_free(value);
+
+    return 0;
 }
 
 static void property_release_str(struct uc_struct *uc, Object *obj, const char *name,
@@ -1452,7 +1457,7 @@ static void property_release_str(struct uc_struct *uc, Object *obj, const char *
 
 void object_property_add_str(Object *obj, const char *name,
                            char *(*get)(struct uc_struct *uc, Object *, Error **),
-                           void (*set)(struct uc_struct *uc, Object *, const char *, Error **),
+                           int (*set)(struct uc_struct *uc, Object *, const char *, Error **),
                            Error **errp)
 {
     Error *local_err = NULL;
@@ -1475,7 +1480,7 @@ void object_property_add_str(Object *obj, const char *name,
 typedef struct BoolProperty
 {
     bool (*get)(struct uc_struct *uc, Object *, Error **);
-    void (*set)(struct uc_struct *uc, Object *, bool, Error **);
+    int (*set)(struct uc_struct *uc, Object *, bool, Error **);
 } BoolProperty;
 
 static void property_get_bool(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
@@ -1488,7 +1493,7 @@ static void property_get_bool(struct uc_struct *uc, Object *obj, Visitor *v, voi
     visit_type_bool(v, &value, name, errp);
 }
 
-static void property_set_bool(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int property_set_bool(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                               const char *name, Error **errp)
 {
     BoolProperty *prop = opaque;
@@ -1498,10 +1503,10 @@ static void property_set_bool(struct uc_struct *uc, Object *obj, Visitor *v, voi
     visit_type_bool(v, &value, name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
 
-    prop->set(uc, obj, value, errp);
+    return prop->set(uc, obj, value, errp);
 }
 
 static void property_release_bool(struct uc_struct *uc, Object *obj, const char *name,
@@ -1513,7 +1518,7 @@ static void property_release_bool(struct uc_struct *uc, Object *obj, const char
 
 void object_property_add_bool(struct uc_struct *uc, Object *obj, const char *name,
                               bool (*get)(struct uc_struct *uc, Object *, Error **),
-                              void (*set)(struct uc_struct *uc, Object *, bool, Error **),
+                              int (*set)(struct uc_struct *uc, Object *, bool, Error **),
                               Error **errp)
 {
     Error *local_err = NULL;
@@ -1611,12 +1616,14 @@ static void property_get_alias(struct uc_struct *uc, Object *obj, struct Visitor
     object_property_get(uc, prop->target_obj, v, prop->target_name, errp);
 }
 
-static void property_set_alias(struct uc_struct *uc, Object *obj, struct Visitor *v, void *opaque,
+static int property_set_alias(struct uc_struct *uc, Object *obj, struct Visitor *v, void *opaque,
                                const char *name, Error **errp)
 {
     AliasProperty *prop = opaque;
 
     object_property_set(uc, prop->target_obj, v, prop->target_name, errp);
+
+    return 0;
 }
 
 static Object *property_resolve_alias(struct uc_struct *uc, Object *obj, void *opaque,
diff --git a/qemu/qom/qom-qobject.c b/qemu/qom/qom-qobject.c
index 9b0172ea..f1579ff2 100644
--- a/qemu/qom/qom-qobject.c
+++ b/qemu/qom/qom-qobject.c
@@ -21,7 +21,7 @@ void object_property_set_qobject(struct uc_struct *uc, Object *obj, QObject *val
 {
     QmpInputVisitor *mi;
     mi = qmp_input_visitor_new(value);
-    object_property_set(uc, obj, qmp_input_get_visitor(mi), name, errp);
+    object_property_set(uc, obj, qmp_input_get_visitor(mi), name, errp);    // qq
 
     qmp_input_visitor_cleanup(mi);
 }
diff --git a/qemu/target-arm/cpu.c b/qemu/target-arm/cpu.c
index d52b56d2..3373be6b 100644
--- a/qemu/target-arm/cpu.c
+++ b/qemu/target-arm/cpu.c
@@ -329,7 +329,7 @@ static void arm_cpu_finalizefn(struct uc_struct *uc, Object *obj, void *opaque)
     g_hash_table_destroy(cpu->cp_regs);
 }
 
-static void arm_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int arm_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     CPUState *cs = CPU(dev);
     ARMCPU *cpu = ARM_CPU(uc, dev);
@@ -399,6 +399,8 @@ static void arm_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **er
     cpu_reset(cs);
 
     acc->parent_realize(uc, dev, errp);
+
+    return 0;
 }
 
 static ObjectClass *arm_cpu_class_by_name(struct uc_struct *uc, const char *cpu_model)
diff --git a/qemu/target-i386/cpu.c b/qemu/target-i386/cpu.c
index 4301b946..d8b58510 100644
--- a/qemu/target-i386/cpu.c
+++ b/qemu/target-i386/cpu.c
@@ -1162,7 +1162,7 @@ static void x86_cpuid_version_get_family(struct uc_struct *uc, Object *obj, Visi
     visit_type_int(v, &value, name, errp);
 }
 
-static void x86_cpuid_version_set_family(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int x86_cpuid_version_set_family(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                                          const char *name, Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
@@ -1175,12 +1175,12 @@ static void x86_cpuid_version_set_family(struct uc_struct *uc, Object *obj, Visi
     visit_type_int(v, &value, name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
     if (value < min || value > max) {
         error_set(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE, "",
                   name ? name : "null", value, min, max);
-        return;
+        return -1;
     }
 
     env->cpuid_version &= ~0xff00f00;
@@ -1189,6 +1189,8 @@ static void x86_cpuid_version_set_family(struct uc_struct *uc, Object *obj, Visi
     } else {
         env->cpuid_version |= value << 8;
     }
+
+    return 0;
 }
 
 static void x86_cpuid_version_get_model(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
@@ -1203,7 +1205,7 @@ static void x86_cpuid_version_get_model(struct uc_struct *uc, Object *obj, Visit
     visit_type_int(v, &value, name, errp);
 }
 
-static void x86_cpuid_version_set_model(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int x86_cpuid_version_set_model(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                                         const char *name, Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
@@ -1216,16 +1218,18 @@ static void x86_cpuid_version_set_model(struct uc_struct *uc, Object *obj, Visit
     visit_type_int(v, &value, name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
     if (value < min || value > max) {
         error_set(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE, "",
                   name ? name : "null", value, min, max);
-        return;
+        return -1;
     }
 
     env->cpuid_version &= ~0xf00f0;
     env->cpuid_version |= ((value & 0xf) << 4) | ((value >> 4) << 16);
+
+    return 0;
 }
 
 static void x86_cpuid_version_get_stepping(struct uc_struct *uc, Object *obj, Visitor *v,
@@ -1240,7 +1244,7 @@ static void x86_cpuid_version_get_stepping(struct uc_struct *uc, Object *obj, Vi
     visit_type_int(v, &value, name, errp);
 }
 
-static void x86_cpuid_version_set_stepping(struct uc_struct *uc, Object *obj, Visitor *v,
+static int x86_cpuid_version_set_stepping(struct uc_struct *uc, Object *obj, Visitor *v,
                                            void *opaque, const char *name,
                                            Error **errp)
 {
@@ -1254,16 +1258,18 @@ static void x86_cpuid_version_set_stepping(struct uc_struct *uc, Object *obj, Vi
     visit_type_int(v, &value, name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
     if (value < min || value > max) {
         error_set(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE, "",
                   name ? name : "null", value, min, max);
-        return;
+        return -1;
     }
 
     env->cpuid_version &= ~0xf;
     env->cpuid_version |= value & 0xf;
+
+    return 0;
 }
 
 static void x86_cpuid_get_level(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
@@ -1274,12 +1280,14 @@ static void x86_cpuid_get_level(struct uc_struct *uc, Object *obj, Visitor *v, v
     visit_type_uint32(v, &cpu->env.cpuid_level, name, errp);
 }
 
-static void x86_cpuid_set_level(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int x86_cpuid_set_level(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                                 const char *name, Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
 
     visit_type_uint32(v, &cpu->env.cpuid_level, name, errp);
+
+    return 0;
 }
 
 static void x86_cpuid_get_xlevel(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
@@ -1290,12 +1298,14 @@ static void x86_cpuid_get_xlevel(struct uc_struct *uc, Object *obj, Visitor *v,
     visit_type_uint32(v, &cpu->env.cpuid_xlevel, name, errp);
 }
 
-static void x86_cpuid_set_xlevel(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int x86_cpuid_set_xlevel(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                                  const char *name, Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
 
     visit_type_uint32(v, &cpu->env.cpuid_xlevel, name, errp);
+
+    return 0;
 }
 
 static char *x86_cpuid_get_vendor(struct uc_struct *uc, Object *obj, Error **errp)
@@ -1310,7 +1320,7 @@ static char *x86_cpuid_get_vendor(struct uc_struct *uc, Object *obj, Error **err
     return value;
 }
 
-static void x86_cpuid_set_vendor(struct uc_struct *uc, Object *obj, const char *value,
+static int x86_cpuid_set_vendor(struct uc_struct *uc, Object *obj, const char *value,
                                  Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
@@ -1320,7 +1330,7 @@ static void x86_cpuid_set_vendor(struct uc_struct *uc, Object *obj, const char *
     if (strlen(value) != CPUID_VENDOR_SZ) {
         error_set(errp, QERR_PROPERTY_VALUE_BAD, "",
                   "vendor", value);
-        return;
+        return -1;
     }
 
     env->cpuid_vendor1 = 0;
@@ -1331,6 +1341,8 @@ static void x86_cpuid_set_vendor(struct uc_struct *uc, Object *obj, const char *
         env->cpuid_vendor2 |= ((uint8_t)value[i + 4]) << (8 * i);
         env->cpuid_vendor3 |= ((uint8_t)value[i + 8]) << (8 * i);
     }
+
+    return 0;
 }
 
 static char *x86_cpuid_get_model_id(struct uc_struct *uc, Object *obj, Error **errp)
@@ -1348,7 +1360,7 @@ static char *x86_cpuid_get_model_id(struct uc_struct *uc, Object *obj, Error **e
     return value;
 }
 
-static void x86_cpuid_set_model_id(struct uc_struct *uc, Object *obj, const char *model_id,
+static int x86_cpuid_set_model_id(struct uc_struct *uc, Object *obj, const char *model_id,
                                    Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
@@ -1368,6 +1380,8 @@ static void x86_cpuid_set_model_id(struct uc_struct *uc, Object *obj, const char
         }
         env->cpuid_model[i >> 2] |= c << (8 * (i & 3));
     }
+
+    return 0;
 }
 
 static void x86_cpuid_get_tsc_freq(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
@@ -1380,7 +1394,7 @@ static void x86_cpuid_get_tsc_freq(struct uc_struct *uc, Object *obj, Visitor *v
     visit_type_int(v, &value, name, errp);
 }
 
-static void x86_cpuid_set_tsc_freq(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int x86_cpuid_set_tsc_freq(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                                    const char *name, Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
@@ -1392,15 +1406,17 @@ static void x86_cpuid_set_tsc_freq(struct uc_struct *uc, Object *obj, Visitor *v
     visit_type_int(v, &value, name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
     if (value < min || value > max) {
         error_set(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE, "",
                   name ? name : "null", value, min, max);
-        return;
+        return -1;
     }
 
     cpu->env.tsc_khz = value / 1000;
+
+    return 0;
 }
 
 static void x86_cpuid_get_apic_id(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
@@ -1412,7 +1428,7 @@ static void x86_cpuid_get_apic_id(struct uc_struct *uc, Object *obj, Visitor *v,
     visit_type_int(v, &value, name, errp);
 }
 
-static void x86_cpuid_set_apic_id(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
+static int x86_cpuid_set_apic_id(struct uc_struct *uc, Object *obj, Visitor *v, void *opaque,
                                   const char *name, Error **errp)
 {
     X86CPU *cpu = X86_CPU(uc, obj);
@@ -1425,26 +1441,28 @@ static void x86_cpuid_set_apic_id(struct uc_struct *uc, Object *obj, Visitor *v,
     if (dev->realized) {
         error_setg(errp, "Attempt to set property '%s' on '%s' after "
                    "it was realized", name, object_get_typename(obj));
-        return;
+        return -1;
     }
 
     visit_type_int(v, &value, name, &error);
     if (error) {
         error_propagate(errp, error);
-        return;
+        return -1;
     }
     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;
+        return -1;
     }
 
     if ((value != cpu->env.cpuid_apic_id) && cpu_exists(uc, value)) {
         error_setg(errp, "CPU with APIC ID %" PRIi64 " exists", value);
-        return;
+        return -1;
     }
     cpu->env.cpuid_apic_id = value;
+
+    return 0;
 }
 
 /* Generic getter for "feature-words" and "filtered-features" properties */
@@ -2249,7 +2267,7 @@ static void x86_cpu_apic_realize(X86CPU *cpu, Error **errp)
 #define IS_AMD_CPU(env) ((env)->cpuid_vendor1 == CPUID_VENDOR_AMD_1 && \
                          (env)->cpuid_vendor2 == CPUID_VENDOR_AMD_2 && \
                          (env)->cpuid_vendor3 == CPUID_VENDOR_AMD_3)
-static void x86_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int x86_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     CPUState *cs = CPU(dev);
     X86CPU *cpu = X86_CPU(uc, dev);
@@ -2270,7 +2288,6 @@ static void x86_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **er
            & CPUID_EXT2_AMD_ALIASES);
     }
 
-
     if (x86_cpu_filter_features(cpu) && cpu->enforce_cpuid) {
         error_setg(&local_err,
                        "TCG doesn't support requested features");
@@ -2289,7 +2306,8 @@ static void x86_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **er
 #endif
 
     mce_init(cpu);
-    qemu_init_vcpu(cs);
+    if (qemu_init_vcpu(cs))
+        return -1;
 
     x86_cpu_apic_realize(cpu, &local_err);
     if (local_err != NULL) {
@@ -2301,8 +2319,10 @@ static void x86_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **er
 out:
     if (local_err != NULL) {
         error_propagate(errp, local_err);
-        return;
+        return -1;
     }
+
+    return 0;
 }
 
 /* Enables contiguous-apic-ID mode, for compatibility */
diff --git a/qemu/target-m68k/cpu.c b/qemu/target-m68k/cpu.c
index 140179b0..19e00067 100644
--- a/qemu/target-m68k/cpu.c
+++ b/qemu/target-m68k/cpu.c
@@ -146,7 +146,7 @@ static const M68kCPUInfo m68k_cpus[] = {
     { .name = "any",   .instance_init = any_cpu_initfn },
 };
 
-static void m68k_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int m68k_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     CPUState *cs = CPU(dev);
     M68kCPUClass *mcc = M68K_CPU_GET_CLASS(uc, dev);
@@ -155,6 +155,8 @@ static void m68k_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **e
     qemu_init_vcpu(cs);
 
     mcc->parent_realize(cs->uc, dev, errp);
+
+    return 0;
 }
 
 static void m68k_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
diff --git a/qemu/target-mips/cpu.c b/qemu/target-mips/cpu.c
index 2cb6e14a..00672634 100644
--- a/qemu/target-mips/cpu.c
+++ b/qemu/target-mips/cpu.c
@@ -92,7 +92,7 @@ static void mips_cpu_reset(CPUState *s)
     cpu_state_reset(env);
 }
 
-static void mips_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int mips_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     CPUState *cs = CPU(dev);
     MIPSCPUClass *mcc = MIPS_CPU_GET_CLASS(uc, dev);
@@ -101,6 +101,8 @@ static void mips_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **e
     qemu_init_vcpu(cs);
 
     mcc->parent_realize(uc, dev, errp);
+
+    return 0;
 }
 
 static void mips_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
diff --git a/qemu/target-sparc/cpu.c b/qemu/target-sparc/cpu.c
index e14c4c55..c3f779b7 100644
--- a/qemu/target-sparc/cpu.c
+++ b/qemu/target-sparc/cpu.c
@@ -783,7 +783,7 @@ static bool sparc_cpu_has_work(CPUState *cs)
         cpu_interrupts_enabled(env);
 }
 
-static void sparc_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
+static int sparc_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **errp)
 {
     SPARCCPUClass *scc = SPARC_CPU_GET_CLASS(uc, dev);
 #if defined(CONFIG_USER_ONLY)
@@ -798,6 +798,8 @@ static void sparc_cpu_realizefn(struct uc_struct *uc, DeviceState *dev, Error **
     qemu_init_vcpu(CPU(dev));
 
     scc->parent_realize(uc, dev, errp);
+
+    return 0;
 }
 
 static void sparc_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
diff --git a/qemu/util/qemu-thread-posix.c b/qemu/util/qemu-thread-posix.c
index 34632bca..26cba2da 100644
--- a/qemu/util/qemu-thread-posix.c
+++ b/qemu/util/qemu-thread-posix.c
@@ -29,8 +29,8 @@
 
 static void error_exit(int err, const char *msg)
 {
-    fprintf(stderr, "qemu: %s: %s\n", msg, strerror(err));
-    abort();
+    // fprintf(stderr, "qemu: %s: %s\n", msg, strerror(err));
+    // abort();
 }
 
 void qemu_mutex_init(QemuMutex *mutex)
@@ -389,7 +389,7 @@ void qemu_event_wait(QemuEvent *ev)
     }
 }
 
-void qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *name,
+int qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *name,
                        void *(*start_routine)(void*),
                        void *arg, int mode)
 {
@@ -397,20 +397,16 @@ void qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *na
     int err;
     pthread_attr_t attr;
 
-#if 0
-    static int count = 0;
-    count++;
-    printf(">>> create thread %u\n", count);
-#endif
-
     err = pthread_attr_init(&attr);
     if (err) {
         error_exit(err, __func__);
+        return -1;
     }
     if (mode == QEMU_THREAD_DETACHED) {
         err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
         if (err) {
             error_exit(err, __func__);
+            return -1;
         }
     }
 
@@ -418,12 +414,16 @@ void qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *na
     sigfillset(&set);
     pthread_sigmask(SIG_SETMASK, &set, &oldset);
     err = pthread_create(&thread->thread, &attr, start_routine, arg);
-    if (err)
+    if (err) {
         error_exit(err, __func__);
+        return -1;
+    }
 
     pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 
     pthread_attr_destroy(&attr);
+
+    return 0;
 }
 
 void qemu_thread_get_self(struct uc_struct *uc, QemuThread *thread)
diff --git a/qemu/util/qemu-thread-win32.c b/qemu/util/qemu-thread-win32.c
index 3f7f7015..2c2cf4ad 100644
--- a/qemu/util/qemu-thread-win32.c
+++ b/qemu/util/qemu-thread-win32.c
@@ -27,7 +27,7 @@ static void error_exit(int err, const char *msg)
                   NULL, err, 0, (LPTSTR)&pstr, 2, NULL);
     fprintf(stderr, "qemu: %s: %s\n", msg, pstr);
     LocalFree(pstr);
-    abort();
+    //abort();
 }
 
 void qemu_mutex_init(QemuMutex *mutex)
@@ -326,7 +326,7 @@ void *qemu_thread_join(QemuThread *thread)
     return ret;
 }
 
-void qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *name,
+int qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *name,
                        void *(*start_routine)(void *),
                        void *arg, int mode)
 {
@@ -350,9 +350,13 @@ void qemu_thread_create(struct uc_struct *uc, QemuThread *thread, const char *na
                                       data, 0, &thread->tid);
     if (!hThread) {
         error_exit(GetLastError(), __func__);
+        return -1;
     }
+
     CloseHandle(hThread);
     thread->data = (mode == QEMU_THREAD_DETACHED) ? NULL : data;
+
+    return 0;
 }
 
 void qemu_thread_get_self(struct uc_struct *uc, QemuThread *thread)
diff --git a/qemu/vl.c b/qemu/vl.c
index a65a91fa..caf6686f 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -94,8 +94,6 @@ int machine_initialize(struct uc_struct *uc)
     MachineClass *machine_class;
     MachineState *current_machine;
 
-    //printf(">>> starting machine initialize\n");
-
     module_call_init(uc, MODULE_INIT_QOM);
     register_types_object(uc);
     machine_register_types(uc);
@@ -115,11 +113,8 @@ int machine_initialize(struct uc_struct *uc)
         return -2;
     }
 
-    // printf("222\n");
     current_machine = MACHINE(uc, object_new(uc, object_class_get_name(
                     OBJECT_CLASS(machine_class))));
-    //object_property_add_child(object_get_root(), "machine",
-    //                          OBJECT(current_machine), &error_abort);
 
     current_machine->uc = uc;
     uc->cpu_exec_init_all(uc);
@@ -129,14 +124,10 @@ int machine_initialize(struct uc_struct *uc)
 
     qemu_init_cpu_loop(uc);
     qemu_mutex_lock_iothread(uc);
-    //cpu_ticks_init();
-    // printf("333\n");
 
     current_machine->cpu_model = NULL;
-    machine_class->init(uc, current_machine);
 
-    //printf(">>> ending machine initialize\n");
-    return 0;
+    return machine_class->init(uc, current_machine);
 }
 
 void qemu_system_reset_request(struct uc_struct* uc)
diff --git a/uc.c b/uc.c
index cf9e7026..7ff96368 100644
--- a/uc.c
+++ b/uc.c
@@ -97,6 +97,8 @@ const char *uc_strerror(uc_err code)
             return "Fetch from unaligned memory (UC_ERR_FETCH_UNALIGNED)";
         case UC_ERR_HOOK_EXIST:
             return "Hook for this type event already exists (UC_ERR_HOOK_EXIST)";
+        case UC_ERR_RESOURCE:
+            return "Insufficient resource (UC_ERR_RESOURCE)";
     }
 }
 
@@ -235,7 +237,8 @@ uc_err uc_open(uc_arch arch, uc_mode mode, uc_engine **result)
             return UC_ERR_ARCH;
         }
 
-        machine_initialize(uc);
+        if (machine_initialize(uc))
+            return UC_ERR_RESOURCE;
 
         *result = uc;
 
@@ -502,7 +505,10 @@ uc_err uc_emu_start(uc_engine* uc, uint64_t begin, uint64_t until, uint64_t time
 
     uc->addr_end = until;
 
-    uc->vm_start(uc);
+    if (uc->vm_start(uc)) {
+        return UC_ERR_RESOURCE;
+    }
+
     if (timeout)
         enable_emu_timer(uc, timeout * 1000);   // microseconds -> nanoseconds
     uc->pause_all_vcpus(uc);