diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c
index dba99315e37f..e327d90afd05 100644
--- a/accel/tcg/tcg-all.c
+++ b/accel/tcg/tcg-all.c
@@ -28,7 +28,7 @@
 #include "sysemu/sysemu.h"
 #include "qom/object.h"
 
-int tcg_tb_size;
+unsigned long tcg_tb_size;
 static bool tcg_allowed = true;
 
 static int tcg_init(MachineState *ms)
diff --git a/include/sysemu/accel.h b/include/sysemu/accel.h
index ecc5c8462171..5a632cee1d97 100644
--- a/include/sysemu/accel.h
+++ b/include/sysemu/accel.h
@@ -63,7 +63,7 @@ typedef struct AccelClass {
 #define ACCEL_GET_CLASS(obj) \
     OBJECT_GET_CLASS(AccelClass, (obj), TYPE_ACCEL)
 
-extern int tcg_tb_size;
+extern unsigned long tcg_tb_size;
 
 void configure_accelerator(MachineState *ms);
 /* Register accelerator specific global properties */
diff --git a/vl.c b/vl.c
index 36ff3f4345b5..ea8ef5fd38c9 100644
--- a/vl.c
+++ b/vl.c
@@ -3933,9 +3933,9 @@ int main(int argc, char **argv, char **envp)
                 configure_rtc(opts);
                 break;
             case QEMU_OPTION_tb_size:
-                tcg_tb_size = strtol(optarg, NULL, 0);
-                if (tcg_tb_size < 0) {
-                    tcg_tb_size = 0;
+                if (qemu_strtoul(optarg, NULL, 0, &tcg_tb_size) < 0) {
+                    error_report("Invalid argument to -tb-size");
+                    exit(1);
                 }
                 break;
             case QEMU_OPTION_icount: