1 files changed, 106 insertions, 0 deletions
diff --git a/system/balloon.c b/system/balloon.c
new file mode 100644
index 0000000000..e0e8969a4b
--- /dev/null
+++ b/system/balloon.c
@@ -0,0 +1,106 @@
+/*
+ * Generic Balloon handlers and management
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (C) 2011 Red Hat, Inc.
+ * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/atomic.h"
+#include "sysemu/kvm.h"
+#include "sysemu/balloon.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-machine.h"
+#include "qapi/qmp/qerror.h"
+#include "trace.h"
+
+static QEMUBalloonEvent *balloon_event_fn;
+static QEMUBalloonStatus *balloon_stat_fn;
+static void *balloon_opaque;
+
+static bool have_balloon(Error **errp)
+{
+    if (kvm_enabled() && !kvm_has_sync_mmu()) {
+        error_set(errp, ERROR_CLASS_KVM_MISSING_CAP,
+                  "Using KVM without synchronous MMU, balloon unavailable");
+        return false;
+    }
+    if (!balloon_event_fn) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
+                  "No balloon device has been activated");
+        return false;
+    }
+    return true;
+}
+
+int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
+                             QEMUBalloonStatus *stat_func, void *opaque)
+{
+    if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
+        /* We're already registered one balloon handler.  How many can
+         * a guest really have?
+         */
+        return -1;
+    }
+    balloon_event_fn = event_func;
+    balloon_stat_fn = stat_func;
+    balloon_opaque = opaque;
+    return 0;
+}
+
+void qemu_remove_balloon_handler(void *opaque)
+{
+    if (balloon_opaque != opaque) {
+        return;
+    }
+    balloon_event_fn = NULL;
+    balloon_stat_fn = NULL;
+    balloon_opaque = NULL;
+}
+
+BalloonInfo *qmp_query_balloon(Error **errp)
+{
+    BalloonInfo *info;
+
+    if (!have_balloon(errp)) {
+        return NULL;
+    }
+
+    info = g_malloc0(sizeof(*info));
+    balloon_stat_fn(balloon_opaque, info);
+    return info;
+}
+
+void qmp_balloon(int64_t target, Error **errp)
+{
+    if (!have_balloon(errp)) {
+        return;
+    }
+
+    if (target <= 0) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
+        return;
+    }
+
+    trace_balloon_event(balloon_opaque, target);
+    balloon_event_fn(balloon_opaque, target);
+}