diff --git a/tests/drivers/ipm/prj.conf b/tests/drivers/ipm/prj.conf
index f92214c24f3c8..c003e22202a43 100644
--- a/tests/drivers/ipm/prj.conf
+++ b/tests/drivers/ipm/prj.conf
@@ -5,3 +5,4 @@ CONFIG_STDOUT_CONSOLE=n
 CONFIG_IPM_CONSOLE_RECEIVER=y
 CONFIG_IPM_CONSOLE_SENDER=y
 CONFIG_IRQ_OFFLOAD=y
+CONFIG_MP_NUM_CPUS=1
diff --git a/tests/drivers/ipm/testcase.yaml b/tests/drivers/ipm/testcase.yaml
index c3092e543941e..2c346c9b058a9 100644
--- a/tests/drivers/ipm/testcase.yaml
+++ b/tests/drivers/ipm/testcase.yaml
@@ -1,5 +1,4 @@
 tests:
   peripheral.mailbox:
     arch_exclude: posix xtensa
-    platform_exclude: qemu_x86_64 # see issue #12478
     tags: drivers ipc