Wrapper function to wait on condition for the main loop mutex

Introduce a wrapper function to wait on condition for
the main loop mutex. This function atomically releases
the main loop mutex and causes the calling thread to
block on the condition. This wrapper is required because
qemu_global_mutex is a static variable.

Signed-off-by: Aravinda Prasad <arawinda.p@gmail.com>
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20200130184423.20519-2-ganeshgr@linux.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

2 files changed, 13 insertions, 0 deletions

diff --git a/cpus.c b/cpus.c
index b612116f95..b4f8b84b61 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1839,6 +1839,11 @@ void qemu_mutex_unlock_iothread(void)
     qemu_mutex_unlock(&qemu_global_mutex);
 }
 
+void qemu_cond_wait_iothread(QemuCond *cond)
+{
+    qemu_cond_wait(cond, &qemu_global_mutex);
+}
+
 static bool all_vcpus_paused(void)
 {
     CPUState *cpu;
diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index f6ba78ea73..a6d20b0719 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -295,6 +295,14 @@ void qemu_mutex_lock_iothread_impl(const char *file, int line);
  */
 void qemu_mutex_unlock_iothread(void);
 
+/*
+ * qemu_cond_wait_iothread: Wait on condition for the main loop mutex
+ *
+ * This function atomically releases the main loop mutex and causes
+ * the calling thread to block on the condition.
+ */
+void qemu_cond_wait_iothread(QemuCond *cond);
+
 /* internal interfaces */
 
 void qemu_fd_register(int fd);