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-rw-r--r--balloon.c106
1 files changed, 106 insertions, 0 deletions
diff --git a/balloon.c b/balloon.c
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+++ b/balloon.c
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+/*
+ * 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-common.h"
+#include "exec/cpu-common.h"
+#include "sysemu/kvm.h"
+#include "sysemu/balloon.h"
+#include "trace.h"
+#include "qmp-commands.h"
+#include "qapi/qmp/qerror.h"
+#include "qapi/qmp/qjson.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);
+}