add --no-reboot in lab2_result

labcodes_answer/lab2_result/Makefile

@@ -209,12 +209,12 @@ QEMUOPTS = -hda $(UCOREIMG)
 
 .PHONY: qemu qemu-nox gdb debug debug-mon debug-nox
 qemu-mon: targets
-	$(V)$(QEMU) -monitor stdio $(QEMUOPTS) -serial null
+	$(V)$(QEMU) -no-reboot -monitor stdio $(QEMUOPTS) -serial null
 qemu: targets
-	$(V)$(QEMU) -parallel stdio $(QEMUOPTS) -serial null
+	$(V)$(QEMU) -no-reboot -parallel stdio $(QEMUOPTS) -serial null
 
 qemu-nox: targets
-	$(V)$(QEMU) -serial mon:stdio $(QEMUOPTS) -nographic
+	$(V)$(QEMU) -no-reboot -serial mon:stdio $(QEMUOPTS) -nographic
 
 gdb:
 	$(V)$(GDB) -q -x tools/gdbinit