You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

126 lines
3.6KB

  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. #include "qemu/osdep.h"
  27. #include "qemu-common.h"
  28. #include "qemu/atomic.h"
  29. #include "exec/cpu-common.h"
  30. #include "sysemu/kvm.h"
  31. #include "sysemu/balloon.h"
  32. #include "trace-root.h"
  33. #include "qapi/error.h"
  34. #include "qapi/qapi-commands-misc.h"
  35. #include "qapi/qmp/qerror.h"
  36. static QEMUBalloonEvent *balloon_event_fn;
  37. static QEMUBalloonStatus *balloon_stat_fn;
  38. static void *balloon_opaque;
  39. static int balloon_inhibit_count;
  40. bool qemu_balloon_is_inhibited(void)
  41. {
  42. return atomic_read(&balloon_inhibit_count) > 0;
  43. }
  44. void qemu_balloon_inhibit(bool state)
  45. {
  46. if (state) {
  47. atomic_inc(&balloon_inhibit_count);
  48. } else {
  49. atomic_dec(&balloon_inhibit_count);
  50. }
  51. assert(atomic_read(&balloon_inhibit_count) >= 0);
  52. }
  53. static bool have_balloon(Error **errp)
  54. {
  55. if (kvm_enabled() && !kvm_has_sync_mmu()) {
  56. error_set(errp, ERROR_CLASS_KVM_MISSING_CAP,
  57. "Using KVM without synchronous MMU, balloon unavailable");
  58. return false;
  59. }
  60. if (!balloon_event_fn) {
  61. error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
  62. "No balloon device has been activated");
  63. return false;
  64. }
  65. return true;
  66. }
  67. int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
  68. QEMUBalloonStatus *stat_func, void *opaque)
  69. {
  70. if (balloon_event_fn || balloon_stat_fn || balloon_opaque) {
  71. /* We're already registered one balloon handler. How many can
  72. * a guest really have?
  73. */
  74. return -1;
  75. }
  76. balloon_event_fn = event_func;
  77. balloon_stat_fn = stat_func;
  78. balloon_opaque = opaque;
  79. return 0;
  80. }
  81. void qemu_remove_balloon_handler(void *opaque)
  82. {
  83. if (balloon_opaque != opaque) {
  84. return;
  85. }
  86. balloon_event_fn = NULL;
  87. balloon_stat_fn = NULL;
  88. balloon_opaque = NULL;
  89. }
  90. BalloonInfo *qmp_query_balloon(Error **errp)
  91. {
  92. BalloonInfo *info;
  93. if (!have_balloon(errp)) {
  94. return NULL;
  95. }
  96. info = g_malloc0(sizeof(*info));
  97. balloon_stat_fn(balloon_opaque, info);
  98. return info;
  99. }
  100. void qmp_balloon(int64_t target, Error **errp)
  101. {
  102. if (!have_balloon(errp)) {
  103. return;
  104. }
  105. if (target <= 0) {
  106. error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "target", "a size");
  107. return;
  108. }
  109. trace_balloon_event(balloon_opaque, target);
  110. balloon_event_fn(balloon_opaque, target);
  111. }