diff --git a/include/uc_priv.h b/include/uc_priv.h
index d235e3e9..2a726cee 100644
--- a/include/uc_priv.h
+++ b/include/uc_priv.h
@@ -58,6 +58,7 @@ 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 void (*uc_cpu_exec_exit_t)(CPUState*);
 
 typedef bool (*uc_args_tcg_enable_t)(struct uc_struct*);
 
@@ -162,6 +163,7 @@ struct uc_struct {
     uc_args_int_t stop_interrupt;   // check if the interrupt should stop emulation
 
     uc_args_uc_t init_arch, cpu_exec_init_all;
+    uc_cpu_exec_exit_t cpu_exec_exit;
     uc_args_int_uc_t vm_start;
     uc_args_tcg_enable_t tcg_enabled;
     uc_args_uc_long_t tcg_exec_init;
diff --git a/qemu/aarch64.h b/qemu/aarch64.h
index d0ea77a8..6b8004dc 100644
--- a/qemu/aarch64.h
+++ b/qemu/aarch64.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_aarch64
 #define cpu_dump_statistics cpu_dump_statistics_aarch64
 #define cpu_exec cpu_exec_aarch64
+#define cpu_exec_exit cpu_exec_exit_aarch64
 #define cpu_exec_init cpu_exec_init_aarch64
 #define cpu_exec_init_all cpu_exec_init_all_aarch64
 #define cpu_exec_step_atomic cpu_exec_step_atomic_aarch64
diff --git a/qemu/aarch64eb.h b/qemu/aarch64eb.h
index d6a79ac7..9205a359 100644
--- a/qemu/aarch64eb.h
+++ b/qemu/aarch64eb.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_aarch64eb
 #define cpu_dump_statistics cpu_dump_statistics_aarch64eb
 #define cpu_exec cpu_exec_aarch64eb
+#define cpu_exec_exit cpu_exec_exit_aarch64eb
 #define cpu_exec_init cpu_exec_init_aarch64eb
 #define cpu_exec_init_all cpu_exec_init_all_aarch64eb
 #define cpu_exec_step_atomic cpu_exec_step_atomic_aarch64eb
diff --git a/qemu/arm.h b/qemu/arm.h
index bd0a792c..2c6d61ca 100644
--- a/qemu/arm.h
+++ b/qemu/arm.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_arm
 #define cpu_dump_statistics cpu_dump_statistics_arm
 #define cpu_exec cpu_exec_arm
+#define cpu_exec_exit cpu_exec_exit_arm
 #define cpu_exec_init cpu_exec_init_arm
 #define cpu_exec_init_all cpu_exec_init_all_arm
 #define cpu_exec_step_atomic cpu_exec_step_atomic_arm
diff --git a/qemu/armeb.h b/qemu/armeb.h
index 2dcb704b..6ba9e124 100644
--- a/qemu/armeb.h
+++ b/qemu/armeb.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_armeb
 #define cpu_dump_statistics cpu_dump_statistics_armeb
 #define cpu_exec cpu_exec_armeb
+#define cpu_exec_exit cpu_exec_exit_armeb
 #define cpu_exec_init cpu_exec_init_armeb
 #define cpu_exec_init_all cpu_exec_init_all_armeb
 #define cpu_exec_step_atomic cpu_exec_step_atomic_armeb
diff --git a/qemu/exec.c b/qemu/exec.c
index aa4c9ebe..6d95c776 100644
--- a/qemu/exec.c
+++ b/qemu/exec.c
@@ -577,18 +577,78 @@ AddressSpace *cpu_get_address_space(CPUState *cpu, int asidx)
 }
 #endif
 
+#ifndef CONFIG_USER_ONLY
+static int cpu_get_free_index(Error **errp)
+{
+    // Unicorn: if'd out
+#if 0
+    int cpu = find_first_zero_bit(cpu_index_map, MAX_CPUMASK_BITS);
+
+    if (cpu >= MAX_CPUMASK_BITS) {
+        error_setg(errp, "Trying to use more CPUs than max of %d",
+                   MAX_CPUMASK_BITS);
+        return -1;
+    }
+
+    bitmap_set(cpu_index_map, cpu, 1);
+    return cpu;
+#endif
+    return 0;
+}
+
+void cpu_exec_exit(CPUState *cpu)
+{
+    if (cpu->cpu_index == -1) {
+        /* cpu_index was never allocated by this @cpu or was already freed. */
+        return;
+    }
+
+    // Unicorn: if'd out
+#if 0
+    bitmap_clear(cpu_index_map, cpu->cpu_index, 1);
+#endif
+    cpu->cpu_index = -1;
+}
+#else
+
+static int cpu_get_free_index(Error **errp)
+{
+    // Unicorn: if'd out
+#if 0
+    CPUState *some_cpu;
+    int cpu_index = 0;
+
+    CPU_FOREACH(some_cpu) {
+        cpu_index++;
+    }
+    return cpu_index;
+#endif
+    return 0;
+}
+
+void cpu_exec_exit(CPUState *cpu)
+{
+}
+#endif
+
 void cpu_exec_init(CPUState *cpu, Error **errp, void *opaque)
 {
     struct uc_struct *uc = opaque;
     CPUClass *cc = CPU_GET_CLASS(uc, cpu);
     CPUArchState *env = cpu->env_ptr;
+    Error *local_err = NULL;
 
     cpu->as = NULL;
-    cpu->cpu_index = 0;
     cpu->num_ases = 0;
     cpu->uc = uc;
     env->uc = uc;
 
+    cpu->cpu_index = cpu_get_free_index(&local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
     // TODO: assert uc does not already have a cpu?
     uc->cpu = cpu;
 
diff --git a/qemu/header_gen.py b/qemu/header_gen.py
index 8b8cbe89..fdafd258 100644
--- a/qemu/header_gen.py
+++ b/qemu/header_gen.py
@@ -282,6 +282,7 @@ symbols = (
     'cpu_common_reset',
     'cpu_dump_statistics',
     'cpu_exec',
+    'cpu_exec_exit',
     'cpu_exec_init',
     'cpu_exec_init_all',
     'cpu_exec_step_atomic',
diff --git a/qemu/include/qom/cpu.h b/qemu/include/qom/cpu.h
index 0345167c..50e6f0b3 100644
--- a/qemu/include/qom/cpu.h
+++ b/qemu/include/qom/cpu.h
@@ -807,6 +807,7 @@ static inline bool cpu_breakpoint_test(CPUState *cpu, vaddr pc, int mask)
 
 void QEMU_NORETURN cpu_abort(CPUState *cpu, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
+void cpu_exec_exit(CPUState *cpu);
 
 void cpu_register_types(struct uc_struct *uc);
 
diff --git a/qemu/m68k.h b/qemu/m68k.h
index ecd7499b..32513a5f 100644
--- a/qemu/m68k.h
+++ b/qemu/m68k.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_m68k
 #define cpu_dump_statistics cpu_dump_statistics_m68k
 #define cpu_exec cpu_exec_m68k
+#define cpu_exec_exit cpu_exec_exit_m68k
 #define cpu_exec_init cpu_exec_init_m68k
 #define cpu_exec_init_all cpu_exec_init_all_m68k
 #define cpu_exec_step_atomic cpu_exec_step_atomic_m68k
diff --git a/qemu/mips.h b/qemu/mips.h
index d66d73a6..8b539661 100644
--- a/qemu/mips.h
+++ b/qemu/mips.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_mips
 #define cpu_dump_statistics cpu_dump_statistics_mips
 #define cpu_exec cpu_exec_mips
+#define cpu_exec_exit cpu_exec_exit_mips
 #define cpu_exec_init cpu_exec_init_mips
 #define cpu_exec_init_all cpu_exec_init_all_mips
 #define cpu_exec_step_atomic cpu_exec_step_atomic_mips
diff --git a/qemu/mips64.h b/qemu/mips64.h
index 42e318b3..9010919b 100644
--- a/qemu/mips64.h
+++ b/qemu/mips64.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_mips64
 #define cpu_dump_statistics cpu_dump_statistics_mips64
 #define cpu_exec cpu_exec_mips64
+#define cpu_exec_exit cpu_exec_exit_mips64
 #define cpu_exec_init cpu_exec_init_mips64
 #define cpu_exec_init_all cpu_exec_init_all_mips64
 #define cpu_exec_step_atomic cpu_exec_step_atomic_mips64
diff --git a/qemu/mips64el.h b/qemu/mips64el.h
index b281b9aa..a2e44acd 100644
--- a/qemu/mips64el.h
+++ b/qemu/mips64el.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_mips64el
 #define cpu_dump_statistics cpu_dump_statistics_mips64el
 #define cpu_exec cpu_exec_mips64el
+#define cpu_exec_exit cpu_exec_exit_mips64el
 #define cpu_exec_init cpu_exec_init_mips64el
 #define cpu_exec_init_all cpu_exec_init_all_mips64el
 #define cpu_exec_step_atomic cpu_exec_step_atomic_mips64el
diff --git a/qemu/mipsel.h b/qemu/mipsel.h
index 81df74e8..6ff8943e 100644
--- a/qemu/mipsel.h
+++ b/qemu/mipsel.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_mipsel
 #define cpu_dump_statistics cpu_dump_statistics_mipsel
 #define cpu_exec cpu_exec_mipsel
+#define cpu_exec_exit cpu_exec_exit_mipsel
 #define cpu_exec_init cpu_exec_init_mipsel
 #define cpu_exec_init_all cpu_exec_init_all_mipsel
 #define cpu_exec_step_atomic cpu_exec_step_atomic_mipsel
diff --git a/qemu/powerpc.h b/qemu/powerpc.h
index 4a0946bf..76036bd9 100644
--- a/qemu/powerpc.h
+++ b/qemu/powerpc.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_powerpc
 #define cpu_dump_statistics cpu_dump_statistics_powerpc
 #define cpu_exec cpu_exec_powerpc
+#define cpu_exec_exit cpu_exec_exit_powerpc
 #define cpu_exec_init cpu_exec_init_powerpc
 #define cpu_exec_init_all cpu_exec_init_all_powerpc
 #define cpu_exec_step_atomic cpu_exec_step_atomic_powerpc
diff --git a/qemu/qom/cpu.c b/qemu/qom/cpu.c
index 9a7cbb6b..b79fd8a0 100644
--- a/qemu/qom/cpu.c
+++ b/qemu/qom/cpu.c
@@ -258,10 +258,16 @@ static void cpu_common_initfn(struct uc_struct *uc, Object *obj, void *opaque)
 {
     CPUState *cpu = CPU(obj);
 
+    cpu->cpu_index = -1;
     QTAILQ_INIT(&cpu->breakpoints);
     QTAILQ_INIT(&cpu->watchpoints);
 }
 
+static void cpu_common_finalize(struct uc_struct *uc, Object *obj, void *opaque)
+{
+    uc->cpu_exec_exit(CPU(obj));
+}
+
 static int64_t cpu_common_get_arch_id(CPUState *cpu)
 {
     return cpu->cpu_index;
@@ -308,7 +314,7 @@ static const TypeInfo cpu_type_info = {
 
     cpu_common_initfn,
     NULL,
-    NULL,
+    cpu_common_finalize,
 
     NULL,
 
diff --git a/qemu/sparc.h b/qemu/sparc.h
index f705f196..2b96df45 100644
--- a/qemu/sparc.h
+++ b/qemu/sparc.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_sparc
 #define cpu_dump_statistics cpu_dump_statistics_sparc
 #define cpu_exec cpu_exec_sparc
+#define cpu_exec_exit cpu_exec_exit_sparc
 #define cpu_exec_init cpu_exec_init_sparc
 #define cpu_exec_init_all cpu_exec_init_all_sparc
 #define cpu_exec_step_atomic cpu_exec_step_atomic_sparc
diff --git a/qemu/sparc64.h b/qemu/sparc64.h
index bca41e2c..9961a6ce 100644
--- a/qemu/sparc64.h
+++ b/qemu/sparc64.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_sparc64
 #define cpu_dump_statistics cpu_dump_statistics_sparc64
 #define cpu_exec cpu_exec_sparc64
+#define cpu_exec_exit cpu_exec_exit_sparc64
 #define cpu_exec_init cpu_exec_init_sparc64
 #define cpu_exec_init_all cpu_exec_init_all_sparc64
 #define cpu_exec_step_atomic cpu_exec_step_atomic_sparc64
diff --git a/qemu/unicorn_common.h b/qemu/unicorn_common.h
index cba7f339..71adf268 100644
--- a/qemu/unicorn_common.h
+++ b/qemu/unicorn_common.h
@@ -100,6 +100,7 @@ static inline void uc_common_init(struct uc_struct* uc)
     uc->tcg_enabled = tcg_enabled;
     uc->tcg_exec_init = tcg_exec_init;
     uc->cpu_exec_init_all = cpu_exec_init_all;
+    uc->cpu_exec_exit = cpu_exec_exit;
     uc->vm_start = vm_start;
     uc->memory_map = memory_map;
     uc->memory_map_ptr = memory_map_ptr;
diff --git a/qemu/x86_64.h b/qemu/x86_64.h
index 26eb361e..d987b500 100644
--- a/qemu/x86_64.h
+++ b/qemu/x86_64.h
@@ -276,6 +276,7 @@
 #define cpu_common_reset cpu_common_reset_x86_64
 #define cpu_dump_statistics cpu_dump_statistics_x86_64
 #define cpu_exec cpu_exec_x86_64
+#define cpu_exec_exit cpu_exec_exit_x86_64
 #define cpu_exec_init cpu_exec_init_x86_64
 #define cpu_exec_init_all cpu_exec_init_all_x86_64
 #define cpu_exec_step_atomic cpu_exec_step_atomic_x86_64