| 1 | /* |
| 2 | * Generic Balloon handlers and management |
| 3 | * |
| 4 | * Copyright (c) 2003-2008 Fabrice Bellard |
| 5 | * Copyright (C) 2011 Red Hat, Inc. |
| 6 | * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com> |
| 7 | * |
| 8 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 9 | * of this software and associated documentation files (the "Software"), to deal |
| 10 | * in the Software without restriction, including without limitation the rights |
| 11 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 12 | * copies of the Software, and to permit persons to whom the Software is |
| 13 | * furnished to do so, subject to the following conditions: |
| 14 | * |
| 15 | * The above copyright notice and this permission notice shall be included in |
| 16 | * all copies or substantial portions of the Software. |
| 17 | * |
| 18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 20 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| 21 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 22 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 23 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| 24 | * THE SOFTWARE. |
| 25 | */ |
| 26 | |
| 27 | #include "qemu/osdep.h" |
| 28 | #include "qemu/atomic.h" |
| 29 | #include "system/kvm.h" |
| 30 | #include "system/balloon.h" |
| 31 | #include "qapi/error.h" |
| 32 | #include "qapi/qapi-commands-machine.h" |
| 33 | #include "qapi/qmp/qerror.h" |
| 34 | #include "trace.h" |
| 35 | |
| 36 | static QEMUBalloonEvent *balloon_event_fn; |
| 37 | static QEMUBalloonStatus *balloon_stat_fn; |
| 38 | static void *balloon_opaque; |
| 39 | |
| 40 | static bool have_balloon(Error **errp) |
| 41 | { |
| 42 | if (kvm_enabled() && !kvm_has_sync_mmu()) { |
| 43 | error_set(errp, ERROR_CLASS_KVM_MISSING_CAP, |
| 44 | "Using KVM without synchronous MMU, balloon unavailable"); |
| 45 | return false; |
| 46 | } |
| 47 | if (!balloon_event_fn) { |
| 48 | error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE, |
| 49 | "No balloon device has been activated"); |
| 50 | return false; |
| 51 | } |
| 52 | return true; |
| 53 | } |
| 54 | |
| 55 | int qemu_add_balloon_handler(QEMUBalloonEvent *event_func, |
| 56 | QEMUBalloonStatus *stat_func, void *opaque) |
| 57 | { |
| 58 | if (balloon_event_fn || balloon_stat_fn || balloon_opaque) { |
| 59 | /* We're already registered one balloon handler. How many can |
| 60 | * a guest really have? |
| 61 | */ |
| 62 | return -1; |
| 63 | } |
| 64 | balloon_event_fn = event_func; |
| 65 | balloon_stat_fn = stat_func; |
| 66 | balloon_opaque = opaque; |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | void qemu_remove_balloon_handler(void *opaque) |
| 71 | { |
| 72 | if (balloon_opaque != opaque) { |
| 73 | return; |
| 74 | } |
| 75 | balloon_event_fn = NULL; |
| 76 | balloon_stat_fn = NULL; |
| 77 | balloon_opaque = NULL; |
| 78 | } |
| 79 | |
| 80 | BalloonInfo *qmp_query_balloon(Error **errp) |
| 81 | { |
| 82 | BalloonInfo *info; |
| 83 | |
| 84 | if (!have_balloon(errp)) { |
| 85 | return NULL; |
| 86 | } |
| 87 | |
| 88 | info = g_malloc0(sizeof(*info)); |
| 89 | balloon_stat_fn(balloon_opaque, info); |
| 90 | return info; |
| 91 | } |
| 92 | |
| 93 | void qmp_balloon(int64_t value, Error **errp) |
| 94 | { |
| 95 | if (!have_balloon(errp)) { |
| 96 | return; |
| 97 | } |
| 98 | |
| 99 | if (value <= 0) { |
| 100 | error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "value", "a size"); |
| 101 | return; |
| 102 | } |
| 103 | |
| 104 | trace_balloon_event(balloon_opaque, value); |
| 105 | balloon_event_fn(balloon_opaque, value); |
| 106 | } |