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 "exec/address-spaces.h" 25 #include "qapi/error.h" 26 #include "qapi/qapi-events-misc.h" 27 #include "qapi/visitor.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()) { 39 qemu_madvise(addr, BALLOON_PAGE_SIZE, 40 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); 41 } 42 } 43 44 static const char *balloon_stat_names[] = { 45 [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", 46 [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", 47 [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", 48 [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", 49 [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", 50 [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", 51 [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory", 52 [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches", 53 [VIRTIO_BALLOON_S_HTLB_PGALLOC] = "stat-htlb-pgalloc", 54 [VIRTIO_BALLOON_S_HTLB_PGFAIL] = "stat-htlb-pgfail", 55 [VIRTIO_BALLOON_S_NR] = NULL 56 }; 57 58 /* 59 * reset_stats - Mark all items in the stats array as unset 60 * 61 * This function needs to be called at device initialization and before 62 * updating to a set of newly-generated stats. This will ensure that no 63 * stale values stick around in case the guest reports a subset of the supported 64 * statistics. 65 */ 66 static inline void reset_stats(VirtIOBalloon *dev) 67 { 68 int i; 69 for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); 70 } 71 72 static bool balloon_stats_supported(const VirtIOBalloon *s) 73 { 74 VirtIODevice *vdev = VIRTIO_DEVICE(s); 75 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); 76 } 77 78 static bool balloon_stats_enabled(const VirtIOBalloon *s) 79 { 80 return s->stats_poll_interval > 0; 81 } 82 83 static void balloon_stats_destroy_timer(VirtIOBalloon *s) 84 { 85 if (balloon_stats_enabled(s)) { 86 timer_del(s->stats_timer); 87 timer_free(s->stats_timer); 88 s->stats_timer = NULL; 89 s->stats_poll_interval = 0; 90 } 91 } 92 93 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs) 94 { 95 timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); 96 } 97 98 static void balloon_stats_poll_cb(void *opaque) 99 { 100 VirtIOBalloon *s = opaque; 101 VirtIODevice *vdev = VIRTIO_DEVICE(s); 102 103 if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) { 104 /* re-schedule */ 105 balloon_stats_change_timer(s, s->stats_poll_interval); 106 return; 107 } 108 109 virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset); 110 virtio_notify(vdev, s->svq); 111 g_free(s->stats_vq_elem); 112 s->stats_vq_elem = NULL; 113 } 114 115 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name, 116 void *opaque, Error **errp) 117 { 118 Error *err = NULL; 119 VirtIOBalloon *s = opaque; 120 int i; 121 122 visit_start_struct(v, name, NULL, 0, &err); 123 if (err) { 124 goto out; 125 } 126 visit_type_int(v, "last-update", &s->stats_last_update, &err); 127 if (err) { 128 goto out_end; 129 } 130 131 visit_start_struct(v, "stats", NULL, 0, &err); 132 if (err) { 133 goto out_end; 134 } 135 for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) { 136 visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err); 137 if (err) { 138 goto out_nested; 139 } 140 } 141 visit_check_struct(v, &err); 142 out_nested: 143 visit_end_struct(v, NULL); 144 145 if (!err) { 146 visit_check_struct(v, &err); 147 } 148 out_end: 149 visit_end_struct(v, NULL); 150 out: 151 error_propagate(errp, err); 152 } 153 154 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v, 155 const char *name, void *opaque, 156 Error **errp) 157 { 158 VirtIOBalloon *s = opaque; 159 visit_type_int(v, name, &s->stats_poll_interval, errp); 160 } 161 162 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, 163 const char *name, void *opaque, 164 Error **errp) 165 { 166 VirtIOBalloon *s = opaque; 167 Error *local_err = NULL; 168 int64_t value; 169 170 visit_type_int(v, name, &value, &local_err); 171 if (local_err) { 172 error_propagate(errp, local_err); 173 return; 174 } 175 176 if (value < 0) { 177 error_setg(errp, "timer value must be greater than zero"); 178 return; 179 } 180 181 if (value > UINT32_MAX) { 182 error_setg(errp, "timer value is too big"); 183 return; 184 } 185 186 if (value == s->stats_poll_interval) { 187 return; 188 } 189 190 if (value == 0) { 191 /* timer=0 disables the timer */ 192 balloon_stats_destroy_timer(s); 193 return; 194 } 195 196 if (balloon_stats_enabled(s)) { 197 /* timer interval change */ 198 s->stats_poll_interval = value; 199 balloon_stats_change_timer(s, value); 200 return; 201 } 202 203 /* create a new timer */ 204 g_assert(s->stats_timer == NULL); 205 s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); 206 s->stats_poll_interval = value; 207 balloon_stats_change_timer(s, 0); 208 } 209 210 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 211 { 212 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 213 VirtQueueElement *elem; 214 MemoryRegionSection section; 215 216 for (;;) { 217 size_t offset = 0; 218 uint32_t pfn; 219 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 220 if (!elem) { 221 return; 222 } 223 224 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) { 225 ram_addr_t pa; 226 ram_addr_t addr; 227 int p = virtio_ldl_p(vdev, &pfn); 228 229 pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT; 230 offset += 4; 231 232 /* FIXME: remove get_system_memory(), but how? */ 233 section = memory_region_find(get_system_memory(), pa, 1); 234 if (!int128_nz(section.size) || 235 !memory_region_is_ram(section.mr) || 236 memory_region_is_rom(section.mr) || 237 memory_region_is_romd(section.mr)) { 238 trace_virtio_balloon_bad_addr(pa); 239 memory_region_unref(section.mr); 240 continue; 241 } 242 243 trace_virtio_balloon_handle_output(memory_region_name(section.mr), 244 pa); 245 /* Using memory_region_get_ram_ptr is bending the rules a bit, but 246 should be OK because we only want a single page. */ 247 addr = section.offset_within_region; 248 balloon_page(memory_region_get_ram_ptr(section.mr) + addr, 249 !!(vq == s->dvq)); 250 memory_region_unref(section.mr); 251 } 252 253 virtqueue_push(vq, elem, offset); 254 virtio_notify(vdev, vq); 255 g_free(elem); 256 } 257 } 258 259 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) 260 { 261 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 262 VirtQueueElement *elem; 263 VirtIOBalloonStat stat; 264 size_t offset = 0; 265 qemu_timeval tv; 266 267 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 268 if (!elem) { 269 goto out; 270 } 271 272 if (s->stats_vq_elem != NULL) { 273 /* This should never happen if the driver follows the spec. */ 274 virtqueue_push(vq, s->stats_vq_elem, 0); 275 virtio_notify(vdev, vq); 276 g_free(s->stats_vq_elem); 277 } 278 279 s->stats_vq_elem = elem; 280 281 /* Initialize the stats to get rid of any stale values. This is only 282 * needed to handle the case where a guest supports fewer stats than it 283 * used to (ie. it has booted into an old kernel). 284 */ 285 reset_stats(s); 286 287 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) 288 == sizeof(stat)) { 289 uint16_t tag = virtio_tswap16(vdev, stat.tag); 290 uint64_t val = virtio_tswap64(vdev, stat.val); 291 292 offset += sizeof(stat); 293 if (tag < VIRTIO_BALLOON_S_NR) 294 s->stats[tag] = val; 295 } 296 s->stats_vq_offset = offset; 297 298 if (qemu_gettimeofday(&tv) < 0) { 299 warn_report("%s: failed to get time of day", __func__); 300 goto out; 301 } 302 303 s->stats_last_update = tv.tv_sec; 304 305 out: 306 if (balloon_stats_enabled(s)) { 307 balloon_stats_change_timer(s, s->stats_poll_interval); 308 } 309 } 310 311 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) 312 { 313 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 314 struct virtio_balloon_config config; 315 316 config.num_pages = cpu_to_le32(dev->num_pages); 317 config.actual = cpu_to_le32(dev->actual); 318 319 trace_virtio_balloon_get_config(config.num_pages, config.actual); 320 memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); 321 } 322 323 static int build_dimm_list(Object *obj, void *opaque) 324 { 325 GSList **list = opaque; 326 327 if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { 328 DeviceState *dev = DEVICE(obj); 329 if (dev->realized) { /* only realized DIMMs matter */ 330 *list = g_slist_prepend(*list, dev); 331 } 332 } 333 334 object_child_foreach(obj, build_dimm_list, opaque); 335 return 0; 336 } 337 338 static ram_addr_t get_current_ram_size(void) 339 { 340 GSList *list = NULL, *item; 341 ram_addr_t size = ram_size; 342 343 build_dimm_list(qdev_get_machine(), &list); 344 for (item = list; item; item = g_slist_next(item)) { 345 Object *obj = OBJECT(item->data); 346 if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { 347 size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, 348 &error_abort); 349 } 350 } 351 g_slist_free(list); 352 353 return size; 354 } 355 356 static void virtio_balloon_set_config(VirtIODevice *vdev, 357 const uint8_t *config_data) 358 { 359 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 360 struct virtio_balloon_config config; 361 uint32_t oldactual = dev->actual; 362 ram_addr_t vm_ram_size = get_current_ram_size(); 363 364 memcpy(&config, config_data, sizeof(struct virtio_balloon_config)); 365 dev->actual = le32_to_cpu(config.actual); 366 if (dev->actual != oldactual) { 367 qapi_event_send_balloon_change(vm_ram_size - 368 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT), 369 &error_abort); 370 } 371 trace_virtio_balloon_set_config(dev->actual, oldactual); 372 } 373 374 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, 375 Error **errp) 376 { 377 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 378 f |= dev->host_features; 379 virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); 380 return f; 381 } 382 383 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 384 { 385 VirtIOBalloon *dev = opaque; 386 info->actual = get_current_ram_size() - ((uint64_t) dev->actual << 387 VIRTIO_BALLOON_PFN_SHIFT); 388 } 389 390 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 391 { 392 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 393 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 394 ram_addr_t vm_ram_size = get_current_ram_size(); 395 396 if (target > vm_ram_size) { 397 target = vm_ram_size; 398 } 399 if (target) { 400 dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 401 virtio_notify_config(vdev); 402 } 403 trace_virtio_balloon_to_target(target, dev->num_pages); 404 } 405 406 static int virtio_balloon_post_load_device(void *opaque, int version_id) 407 { 408 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 409 410 if (balloon_stats_enabled(s)) { 411 balloon_stats_change_timer(s, s->stats_poll_interval); 412 } 413 return 0; 414 } 415 416 static const VMStateDescription vmstate_virtio_balloon_device = { 417 .name = "virtio-balloon-device", 418 .version_id = 1, 419 .minimum_version_id = 1, 420 .post_load = virtio_balloon_post_load_device, 421 .fields = (VMStateField[]) { 422 VMSTATE_UINT32(num_pages, VirtIOBalloon), 423 VMSTATE_UINT32(actual, VirtIOBalloon), 424 VMSTATE_END_OF_LIST() 425 }, 426 }; 427 428 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 429 { 430 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 431 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 432 int ret; 433 434 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 435 sizeof(struct virtio_balloon_config)); 436 437 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 438 virtio_balloon_stat, s); 439 440 if (ret < 0) { 441 error_setg(errp, "Only one balloon device is supported"); 442 virtio_cleanup(vdev); 443 return; 444 } 445 446 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 447 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 448 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 449 450 reset_stats(s); 451 } 452 453 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp) 454 { 455 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 456 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 457 458 balloon_stats_destroy_timer(s); 459 qemu_remove_balloon_handler(s); 460 virtio_cleanup(vdev); 461 } 462 463 static void virtio_balloon_device_reset(VirtIODevice *vdev) 464 { 465 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 466 467 if (s->stats_vq_elem != NULL) { 468 virtqueue_unpop(s->svq, s->stats_vq_elem, 0); 469 g_free(s->stats_vq_elem); 470 s->stats_vq_elem = NULL; 471 } 472 } 473 474 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status) 475 { 476 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 477 478 if (!s->stats_vq_elem && vdev->vm_running && 479 (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) { 480 /* poll stats queue for the element we have discarded when the VM 481 * was stopped */ 482 virtio_balloon_receive_stats(vdev, s->svq); 483 } 484 } 485 486 static void virtio_balloon_instance_init(Object *obj) 487 { 488 VirtIOBalloon *s = VIRTIO_BALLOON(obj); 489 490 object_property_add(obj, "guest-stats", "guest statistics", 491 balloon_stats_get_all, NULL, NULL, s, NULL); 492 493 object_property_add(obj, "guest-stats-polling-interval", "int", 494 balloon_stats_get_poll_interval, 495 balloon_stats_set_poll_interval, 496 NULL, s, NULL); 497 } 498 499 static const VMStateDescription vmstate_virtio_balloon = { 500 .name = "virtio-balloon", 501 .minimum_version_id = 1, 502 .version_id = 1, 503 .fields = (VMStateField[]) { 504 VMSTATE_VIRTIO_DEVICE, 505 VMSTATE_END_OF_LIST() 506 }, 507 }; 508 509 static Property virtio_balloon_properties[] = { 510 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features, 511 VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), 512 DEFINE_PROP_END_OF_LIST(), 513 }; 514 515 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 516 { 517 DeviceClass *dc = DEVICE_CLASS(klass); 518 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 519 520 dc->props = virtio_balloon_properties; 521 dc->vmsd = &vmstate_virtio_balloon; 522 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 523 vdc->realize = virtio_balloon_device_realize; 524 vdc->unrealize = virtio_balloon_device_unrealize; 525 vdc->reset = virtio_balloon_device_reset; 526 vdc->get_config = virtio_balloon_get_config; 527 vdc->set_config = virtio_balloon_set_config; 528 vdc->get_features = virtio_balloon_get_features; 529 vdc->set_status = virtio_balloon_set_status; 530 vdc->vmsd = &vmstate_virtio_balloon_device; 531 } 532 533 static const TypeInfo virtio_balloon_info = { 534 .name = TYPE_VIRTIO_BALLOON, 535 .parent = TYPE_VIRTIO_DEVICE, 536 .instance_size = sizeof(VirtIOBalloon), 537 .instance_init = virtio_balloon_instance_init, 538 .class_init = virtio_balloon_class_init, 539 }; 540 541 static void virtio_register_types(void) 542 { 543 type_register_static(&virtio_balloon_info); 544 } 545 546 type_init(virtio_register_types) 547