/* * 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-common.h" #include "qemu/atomic.h" #include "exec/cpu-common.h" #include "sysemu/kvm.h" #include "sysemu/balloon.h" #include "trace-root.h" #include "qapi/error.h" #include "qapi/qapi-commands-misc.h" #include "qapi/qmp/qerror.h" static QEMUBalloonEvent *balloon_event_fn; static QEMUBalloonStatus *balloon_stat_fn; static void *balloon_opaque; static int balloon_inhibit_count; bool qemu_balloon_is_inhibited(void) { return atomic_read(&balloon_inhibit_count) > 0; } void qemu_balloon_inhibit(bool state) { if (state) { atomic_inc(&balloon_inhibit_count); } else { atomic_dec(&balloon_inhibit_count); } assert(atomic_read(&balloon_inhibit_count) >= 0); } 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); }