1 files changed, 80 insertions, 0 deletions
diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c
new file mode 100644
index 000000000..571ab521f
--- /dev/null
+++ b/util/qemu-coroutine-sleep.c
@@ -0,0 +1,80 @@
+/*
+ * QEMU coroutine sleep
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/coroutine.h"
+#include "qemu/coroutine_int.h"
+#include "qemu/timer.h"
+#include "block/aio.h"
+
+static const char *qemu_co_sleep_ns__scheduled = "qemu_co_sleep_ns";
+
+void qemu_co_sleep_wake(QemuCoSleep *w)
+{
+    Coroutine *co;
+
+    co = w->to_wake;
+    w->to_wake = NULL;
+    if (co) {
+        /* Write of schedule protected by barrier write in aio_co_schedule */
+        const char *scheduled = qatomic_cmpxchg(&co->scheduled,
+                                                qemu_co_sleep_ns__scheduled, NULL);
+
+        assert(scheduled == qemu_co_sleep_ns__scheduled);
+        aio_co_wake(co);
+    }
+}
+
+static void co_sleep_cb(void *opaque)
+{
+    QemuCoSleep *w = opaque;
+    qemu_co_sleep_wake(w);
+}
+
+void coroutine_fn qemu_co_sleep(QemuCoSleep *w)
+{
+    Coroutine *co = qemu_coroutine_self();
+
+    const char *scheduled = qatomic_cmpxchg(&co->scheduled, NULL,
+                                            qemu_co_sleep_ns__scheduled);
+    if (scheduled) {
+        fprintf(stderr,
+                "%s: Co-routine was already scheduled in '%s'\n",
+                __func__, scheduled);
+        abort();
+    }
+
+    w->to_wake = co;
+    qemu_coroutine_yield();
+
+    /* w->to_wake is cleared before resuming this coroutine.  */
+    assert(w->to_wake == NULL);
+}
+
+void coroutine_fn qemu_co_sleep_ns_wakeable(QemuCoSleep *w,
+                                            QEMUClockType type, int64_t ns)
+{
+    AioContext *ctx = qemu_get_current_aio_context();
+    QEMUTimer ts;
+
+    aio_timer_init(ctx, &ts, type, SCALE_NS, co_sleep_cb, w);
+    timer_mod(&ts, qemu_clock_get_ns(type) + ns);
+
+    /*
+     * The timer will fire in the current AiOContext, so the callback
+     * must happen after qemu_co_sleep yields and there is no race
+     * between timer_mod and qemu_co_sleep.
+     */
+    qemu_co_sleep(w);
+    timer_del(&ts);
+}