[PATCH 2/2] numa: prevent usage of -M memory-backend and -numa memdev at the same time

[Igor Mammedov <imammedo@redhat.com>]

Options -M memory-backend and -numa memdev are mutually exclusive,
and if used together, it might lead to a crash in the worst case.
For example when the same backend is used with these options together:
  -m 4G \
  -object memory-backend-ram,id=mem0,size=4G \
  -M pc,memory-backend=mem0 \
  -numa node,memdev=mem0
QEMU will abort with:
   exec.c:2006: qemu_ram_set_idstr: Assertion `!new_block->idstr[0]' failed.

and following backtrace:
    abort ()
    qemu_ram_set_idstr ()
    vmstate_register_ram ()
    vmstate_register_ram_global ()
    machine_consume_memdev ()
    numa_init_memdev_container ()
    numa_complete_configuration ()
    machine_run_board_init ()

add a check to error out in case the user tries to use both options at
the same time.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 hw/core/numa.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/core/numa.c b/hw/core/numa.c
index 316bc50d75..5f81900f88 100644
--- a/hw/core/numa.c
+++ b/hw/core/numa.c
@@ -757,6 +757,11 @@ void numa_complete_configuration(MachineState *ms)
         }
 
         if (!numa_uses_legacy_mem() && mc->default_ram_id) {
+            if (ms->ram_memdev_id) {
+                error_report("'-machine memory-backend' and '-numa memdev'"
+                             " properties are mutually exclusive");
+                exit(1);
+            }
             ms->ram = g_new(MemoryRegion, 1);
             memory_region_init(ms->ram, OBJECT(ms), mc->default_ram_id,
                                ram_size);
-- 
2.18.4