1 /* 2 * Virtio Balloon Device 3 * 4 * Copyright IBM, Corp. 2008 5 * Copyright (C) 2011 Red Hat, Inc. 6 * Copyright (C) 2011 Amit Shah <amit.shah@redhat.com> 7 * 8 * Authors: 9 * Anthony Liguori <aliguori@us.ibm.com> 10 * 11 * This work is licensed under the terms of the GNU GPL, version 2. See 12 * the COPYING file in the top-level directory. 13 * 14 */ 15 16 #include "qemu/osdep.h" 17 #include "qemu/iov.h" 18 #include "qemu/timer.h" 19 #include "qemu-common.h" 20 #include "hw/virtio/virtio.h" 21 #include "hw/mem/pc-dimm.h" 22 #include "sysemu/balloon.h" 23 #include "hw/virtio/virtio-balloon.h" 24 #include "sysemu/kvm.h" 25 #include "exec/address-spaces.h" 26 #include "qapi/visitor.h" 27 #include "qapi-event.h" 28 #include "trace.h" 29 #include "qemu/error-report.h" 30 31 #include "hw/virtio/virtio-bus.h" 32 #include "hw/virtio/virtio-access.h" 33 34 #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) 35 36 static void balloon_page(void *addr, int deflate) 37 { 38 if (!qemu_balloon_is_inhibited() && (!kvm_enabled() || 39 kvm_has_sync_mmu())) { 40 qemu_madvise(addr, BALLOON_PAGE_SIZE, 41 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); 42 } 43 } 44 45 static const char *balloon_stat_names[] = { 46 [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", 47 [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", 48 [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", 49 [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", 50 [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", 51 [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", 52 [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory", 53 [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches", 54 [VIRTIO_BALLOON_S_NR] = NULL 55 }; 56 57 /* 58 * reset_stats - Mark all items in the stats array as unset 59 * 60 * This function needs to be called at device initialization and before 61 * updating to a set of newly-generated stats. This will ensure that no 62 * stale values stick around in case the guest reports a subset of the supported 63 * statistics. 64 */ 65 static inline void reset_stats(VirtIOBalloon *dev) 66 { 67 int i; 68 for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); 69 } 70 71 static bool balloon_stats_supported(const VirtIOBalloon *s) 72 { 73 VirtIODevice *vdev = VIRTIO_DEVICE(s); 74 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); 75 } 76 77 static bool balloon_stats_enabled(const VirtIOBalloon *s) 78 { 79 return s->stats_poll_interval > 0; 80 } 81 82 static void balloon_stats_destroy_timer(VirtIOBalloon *s) 83 { 84 if (balloon_stats_enabled(s)) { 85 timer_del(s->stats_timer); 86 timer_free(s->stats_timer); 87 s->stats_timer = NULL; 88 s->stats_poll_interval = 0; 89 } 90 } 91 92 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs) 93 { 94 timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); 95 } 96 97 static void balloon_stats_poll_cb(void *opaque) 98 { 99 VirtIOBalloon *s = opaque; 100 VirtIODevice *vdev = VIRTIO_DEVICE(s); 101 102 if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) { 103 /* re-schedule */ 104 balloon_stats_change_timer(s, s->stats_poll_interval); 105 return; 106 } 107 108 virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset); 109 virtio_notify(vdev, s->svq); 110 g_free(s->stats_vq_elem); 111 s->stats_vq_elem = NULL; 112 } 113 114 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name, 115 void *opaque, Error **errp) 116 { 117 Error *err = NULL; 118 VirtIOBalloon *s = opaque; 119 int i; 120 121 visit_start_struct(v, name, NULL, 0, &err); 122 if (err) { 123 goto out; 124 } 125 visit_type_int(v, "last-update", &s->stats_last_update, &err); 126 if (err) { 127 goto out_end; 128 } 129 130 visit_start_struct(v, "stats", NULL, 0, &err); 131 if (err) { 132 goto out_end; 133 } 134 for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) { 135 visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err); 136 if (err) { 137 goto out_nested; 138 } 139 } 140 visit_check_struct(v, &err); 141 out_nested: 142 visit_end_struct(v, NULL); 143 144 if (!err) { 145 visit_check_struct(v, &err); 146 } 147 out_end: 148 visit_end_struct(v, NULL); 149 out: 150 error_propagate(errp, err); 151 } 152 153 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v, 154 const char *name, void *opaque, 155 Error **errp) 156 { 157 VirtIOBalloon *s = opaque; 158 visit_type_int(v, name, &s->stats_poll_interval, errp); 159 } 160 161 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, 162 const char *name, void *opaque, 163 Error **errp) 164 { 165 VirtIOBalloon *s = opaque; 166 Error *local_err = NULL; 167 int64_t value; 168 169 visit_type_int(v, name, &value, &local_err); 170 if (local_err) { 171 error_propagate(errp, local_err); 172 return; 173 } 174 175 if (value < 0) { 176 error_setg(errp, "timer value must be greater than zero"); 177 return; 178 } 179 180 if (value > UINT32_MAX) { 181 error_setg(errp, "timer value is too big"); 182 return; 183 } 184 185 if (value == s->stats_poll_interval) { 186 return; 187 } 188 189 if (value == 0) { 190 /* timer=0 disables the timer */ 191 balloon_stats_destroy_timer(s); 192 return; 193 } 194 195 if (balloon_stats_enabled(s)) { 196 /* timer interval change */ 197 s->stats_poll_interval = value; 198 balloon_stats_change_timer(s, value); 199 return; 200 } 201 202 /* create a new timer */ 203 g_assert(s->stats_timer == NULL); 204 s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); 205 s->stats_poll_interval = value; 206 balloon_stats_change_timer(s, 0); 207 } 208 209 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 210 { 211 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 212 VirtQueueElement *elem; 213 MemoryRegionSection section; 214 215 for (;;) { 216 size_t offset = 0; 217 uint32_t pfn; 218 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 219 if (!elem) { 220 return; 221 } 222 223 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) { 224 ram_addr_t pa; 225 ram_addr_t addr; 226 int p = virtio_ldl_p(vdev, &pfn); 227 228 pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT; 229 offset += 4; 230 231 /* FIXME: remove get_system_memory(), but how? */ 232 section = memory_region_find(get_system_memory(), pa, 1); 233 if (!int128_nz(section.size) || 234 !memory_region_is_ram(section.mr) || 235 memory_region_is_rom(section.mr) || 236 memory_region_is_romd(section.mr)) { 237 trace_virtio_balloon_bad_addr(pa); 238 memory_region_unref(section.mr); 239 continue; 240 } 241 242 trace_virtio_balloon_handle_output(memory_region_name(section.mr), 243 pa); 244 /* Using memory_region_get_ram_ptr is bending the rules a bit, but 245 should be OK because we only want a single page. */ 246 addr = section.offset_within_region; 247 balloon_page(memory_region_get_ram_ptr(section.mr) + addr, 248 !!(vq == s->dvq)); 249 memory_region_unref(section.mr); 250 } 251 252 virtqueue_push(vq, elem, offset); 253 virtio_notify(vdev, vq); 254 g_free(elem); 255 } 256 } 257 258 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) 259 { 260 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 261 VirtQueueElement *elem; 262 VirtIOBalloonStat stat; 263 size_t offset = 0; 264 qemu_timeval tv; 265 266 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 267 if (!elem) { 268 goto out; 269 } 270 271 if (s->stats_vq_elem != NULL) { 272 /* This should never happen if the driver follows the spec. */ 273 virtqueue_push(vq, s->stats_vq_elem, 0); 274 virtio_notify(vdev, vq); 275 g_free(s->stats_vq_elem); 276 } 277 278 s->stats_vq_elem = elem; 279 280 /* Initialize the stats to get rid of any stale values. This is only 281 * needed to handle the case where a guest supports fewer stats than it 282 * used to (ie. it has booted into an old kernel). 283 */ 284 reset_stats(s); 285 286 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) 287 == sizeof(stat)) { 288 uint16_t tag = virtio_tswap16(vdev, stat.tag); 289 uint64_t val = virtio_tswap64(vdev, stat.val); 290 291 offset += sizeof(stat); 292 if (tag < VIRTIO_BALLOON_S_NR) 293 s->stats[tag] = val; 294 } 295 s->stats_vq_offset = offset; 296 297 if (qemu_gettimeofday(&tv) < 0) { 298 warn_report("%s: failed to get time of day", __func__); 299 goto out; 300 } 301 302 s->stats_last_update = tv.tv_sec; 303 304 out: 305 if (balloon_stats_enabled(s)) { 306 balloon_stats_change_timer(s, s->stats_poll_interval); 307 } 308 } 309 310 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) 311 { 312 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 313 struct virtio_balloon_config config; 314 315 config.num_pages = cpu_to_le32(dev->num_pages); 316 config.actual = cpu_to_le32(dev->actual); 317 318 trace_virtio_balloon_get_config(config.num_pages, config.actual); 319 memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); 320 } 321 322 static int build_dimm_list(Object *obj, void *opaque) 323 { 324 GSList **list = opaque; 325 326 if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { 327 DeviceState *dev = DEVICE(obj); 328 if (dev->realized) { /* only realized DIMMs matter */ 329 *list = g_slist_prepend(*list, dev); 330 } 331 } 332 333 object_child_foreach(obj, build_dimm_list, opaque); 334 return 0; 335 } 336 337 static ram_addr_t get_current_ram_size(void) 338 { 339 GSList *list = NULL, *item; 340 ram_addr_t size = ram_size; 341 342 build_dimm_list(qdev_get_machine(), &list); 343 for (item = list; item; item = g_slist_next(item)) { 344 Object *obj = OBJECT(item->data); 345 if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { 346 size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, 347 &error_abort); 348 } 349 } 350 g_slist_free(list); 351 352 return size; 353 } 354 355 static void virtio_balloon_set_config(VirtIODevice *vdev, 356 const uint8_t *config_data) 357 { 358 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 359 struct virtio_balloon_config config; 360 uint32_t oldactual = dev->actual; 361 ram_addr_t vm_ram_size = get_current_ram_size(); 362 363 memcpy(&config, config_data, sizeof(struct virtio_balloon_config)); 364 dev->actual = le32_to_cpu(config.actual); 365 if (dev->actual != oldactual) { 366 qapi_event_send_balloon_change(vm_ram_size - 367 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT), 368 &error_abort); 369 } 370 trace_virtio_balloon_set_config(dev->actual, oldactual); 371 } 372 373 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, 374 Error **errp) 375 { 376 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 377 f |= dev->host_features; 378 virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); 379 return f; 380 } 381 382 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 383 { 384 VirtIOBalloon *dev = opaque; 385 info->actual = get_current_ram_size() - ((uint64_t) dev->actual << 386 VIRTIO_BALLOON_PFN_SHIFT); 387 } 388 389 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 390 { 391 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 392 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 393 ram_addr_t vm_ram_size = get_current_ram_size(); 394 395 if (target > vm_ram_size) { 396 target = vm_ram_size; 397 } 398 if (target) { 399 dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 400 virtio_notify_config(vdev); 401 } 402 trace_virtio_balloon_to_target(target, dev->num_pages); 403 } 404 405 static int virtio_balloon_post_load_device(void *opaque, int version_id) 406 { 407 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 408 409 if (balloon_stats_enabled(s)) { 410 balloon_stats_change_timer(s, s->stats_poll_interval); 411 } 412 return 0; 413 } 414 415 static const VMStateDescription vmstate_virtio_balloon_device = { 416 .name = "virtio-balloon-device", 417 .version_id = 1, 418 .minimum_version_id = 1, 419 .post_load = virtio_balloon_post_load_device, 420 .fields = (VMStateField[]) { 421 VMSTATE_UINT32(num_pages, VirtIOBalloon), 422 VMSTATE_UINT32(actual, VirtIOBalloon), 423 VMSTATE_END_OF_LIST() 424 }, 425 }; 426 427 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 428 { 429 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 430 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 431 int ret; 432 433 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 434 sizeof(struct virtio_balloon_config)); 435 436 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 437 virtio_balloon_stat, s); 438 439 if (ret < 0) { 440 error_setg(errp, "Only one balloon device is supported"); 441 virtio_cleanup(vdev); 442 return; 443 } 444 445 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 446 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 447 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 448 449 reset_stats(s); 450 } 451 452 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp) 453 { 454 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 455 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 456 457 balloon_stats_destroy_timer(s); 458 qemu_remove_balloon_handler(s); 459 virtio_cleanup(vdev); 460 } 461 462 static void virtio_balloon_device_reset(VirtIODevice *vdev) 463 { 464 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 465 466 if (s->stats_vq_elem != NULL) { 467 virtqueue_unpop(s->svq, s->stats_vq_elem, 0); 468 g_free(s->stats_vq_elem); 469 s->stats_vq_elem = NULL; 470 } 471 } 472 473 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status) 474 { 475 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 476 477 if (!s->stats_vq_elem && vdev->vm_running && 478 (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) { 479 /* poll stats queue for the element we have discarded when the VM 480 * was stopped */ 481 virtio_balloon_receive_stats(vdev, s->svq); 482 } 483 } 484 485 static void virtio_balloon_instance_init(Object *obj) 486 { 487 VirtIOBalloon *s = VIRTIO_BALLOON(obj); 488 489 object_property_add(obj, "guest-stats", "guest statistics", 490 balloon_stats_get_all, NULL, NULL, s, NULL); 491 492 object_property_add(obj, "guest-stats-polling-interval", "int", 493 balloon_stats_get_poll_interval, 494 balloon_stats_set_poll_interval, 495 NULL, s, NULL); 496 } 497 498 static const VMStateDescription vmstate_virtio_balloon = { 499 .name = "virtio-balloon", 500 .minimum_version_id = 1, 501 .version_id = 1, 502 .fields = (VMStateField[]) { 503 VMSTATE_VIRTIO_DEVICE, 504 VMSTATE_END_OF_LIST() 505 }, 506 }; 507 508 static Property virtio_balloon_properties[] = { 509 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features, 510 VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), 511 DEFINE_PROP_END_OF_LIST(), 512 }; 513 514 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 515 { 516 DeviceClass *dc = DEVICE_CLASS(klass); 517 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 518 519 dc->props = virtio_balloon_properties; 520 dc->vmsd = &vmstate_virtio_balloon; 521 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 522 vdc->realize = virtio_balloon_device_realize; 523 vdc->unrealize = virtio_balloon_device_unrealize; 524 vdc->reset = virtio_balloon_device_reset; 525 vdc->get_config = virtio_balloon_get_config; 526 vdc->set_config = virtio_balloon_set_config; 527 vdc->get_features = virtio_balloon_get_features; 528 vdc->set_status = virtio_balloon_set_status; 529 vdc->vmsd = &vmstate_virtio_balloon_device; 530 } 531 532 static const TypeInfo virtio_balloon_info = { 533 .name = TYPE_VIRTIO_BALLOON, 534 .parent = TYPE_VIRTIO_DEVICE, 535 .instance_size = sizeof(VirtIOBalloon), 536 .instance_init = virtio_balloon_instance_init, 537 .class_init = virtio_balloon_class_init, 538 }; 539 540 static void virtio_register_types(void) 541 { 542 type_register_static(&virtio_balloon_info); 543 } 544 545 type_init(virtio_register_types) 546