qmp: add command "x-oob-test"

This command is only used to test OOB functionality.  It should not be
used for any other purposes.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180309090006.10018-22-peterx@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: grammar tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/qmp.c b/qmp.c
index 7e606d8486..ea3760acb1 100644
--- a/qmp.c
+++ b/qmp.c
@@ -770,3 +770,19 @@ MemoryInfo *qmp_query_memory_size_summary(Error **errp)
 
     return mem_info;
 }
+
+static QemuSemaphore x_oob_test_sem;
+
+static void __attribute__((constructor)) x_oob_test_init(void)
+{
+    qemu_sem_init(&x_oob_test_sem, 0);
+}
+
+void qmp_x_oob_test(bool lock, Error **errp)
+{
+    if (lock) {
+        qemu_sem_wait(&x_oob_test_sem);
+    } else {
+        qemu_sem_post(&x_oob_test_sem);
+    }
+}