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 #include "migration/misc.h" 31 32 #include "hw/virtio/virtio-bus.h" 33 #include "hw/virtio/virtio-access.h" 34 35 #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) 36 37 struct PartiallyBalloonedPage { 38 RAMBlock *rb; 39 ram_addr_t base; 40 unsigned long bitmap[]; 41 }; 42 43 static void balloon_inflate_page(VirtIOBalloon *balloon, 44 MemoryRegion *mr, hwaddr offset) 45 { 46 void *addr = memory_region_get_ram_ptr(mr) + offset; 47 RAMBlock *rb; 48 size_t rb_page_size; 49 int subpages; 50 ram_addr_t ram_offset, host_page_base; 51 52 /* XXX is there a better way to get to the RAMBlock than via a 53 * host address? */ 54 rb = qemu_ram_block_from_host(addr, false, &ram_offset); 55 rb_page_size = qemu_ram_pagesize(rb); 56 host_page_base = ram_offset & ~(rb_page_size - 1); 57 58 if (rb_page_size == BALLOON_PAGE_SIZE) { 59 /* Easy case */ 60 61 ram_block_discard_range(rb, ram_offset, rb_page_size); 62 /* We ignore errors from ram_block_discard_range(), because it 63 * has already reported them, and failing to discard a balloon 64 * page is not fatal */ 65 return; 66 } 67 68 /* Hard case 69 * 70 * We've put a piece of a larger host page into the balloon - we 71 * need to keep track until we have a whole host page to 72 * discard 73 */ 74 warn_report_once( 75 "Balloon used with backing page size > 4kiB, this may not be reliable"); 76 77 subpages = rb_page_size / BALLOON_PAGE_SIZE; 78 79 if (balloon->pbp 80 && (rb != balloon->pbp->rb 81 || host_page_base != balloon->pbp->base)) { 82 /* We've partially ballooned part of a host page, but now 83 * we're trying to balloon part of a different one. Too hard, 84 * give up on the old partial page */ 85 free(balloon->pbp); 86 balloon->pbp = NULL; 87 } 88 89 if (!balloon->pbp) { 90 /* Starting on a new host page */ 91 size_t bitlen = BITS_TO_LONGS(subpages) * sizeof(unsigned long); 92 balloon->pbp = g_malloc0(sizeof(PartiallyBalloonedPage) + bitlen); 93 balloon->pbp->rb = rb; 94 balloon->pbp->base = host_page_base; 95 } 96 97 bitmap_set(balloon->pbp->bitmap, 98 (ram_offset - balloon->pbp->base) / BALLOON_PAGE_SIZE, 99 subpages); 100 101 if (bitmap_full(balloon->pbp->bitmap, subpages)) { 102 /* We've accumulated a full host page, we can actually discard 103 * it now */ 104 105 ram_block_discard_range(rb, balloon->pbp->base, rb_page_size); 106 /* We ignore errors from ram_block_discard_range(), because it 107 * has already reported them, and failing to discard a balloon 108 * page is not fatal */ 109 110 free(balloon->pbp); 111 balloon->pbp = NULL; 112 } 113 } 114 115 static const char *balloon_stat_names[] = { 116 [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", 117 [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", 118 [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", 119 [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", 120 [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", 121 [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", 122 [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory", 123 [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches", 124 [VIRTIO_BALLOON_S_HTLB_PGALLOC] = "stat-htlb-pgalloc", 125 [VIRTIO_BALLOON_S_HTLB_PGFAIL] = "stat-htlb-pgfail", 126 [VIRTIO_BALLOON_S_NR] = NULL 127 }; 128 129 /* 130 * reset_stats - Mark all items in the stats array as unset 131 * 132 * This function needs to be called at device initialization and before 133 * updating to a set of newly-generated stats. This will ensure that no 134 * stale values stick around in case the guest reports a subset of the supported 135 * statistics. 136 */ 137 static inline void reset_stats(VirtIOBalloon *dev) 138 { 139 int i; 140 for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); 141 } 142 143 static bool balloon_stats_supported(const VirtIOBalloon *s) 144 { 145 VirtIODevice *vdev = VIRTIO_DEVICE(s); 146 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); 147 } 148 149 static bool balloon_stats_enabled(const VirtIOBalloon *s) 150 { 151 return s->stats_poll_interval > 0; 152 } 153 154 static void balloon_stats_destroy_timer(VirtIOBalloon *s) 155 { 156 if (balloon_stats_enabled(s)) { 157 timer_del(s->stats_timer); 158 timer_free(s->stats_timer); 159 s->stats_timer = NULL; 160 s->stats_poll_interval = 0; 161 } 162 } 163 164 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs) 165 { 166 timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); 167 } 168 169 static void balloon_stats_poll_cb(void *opaque) 170 { 171 VirtIOBalloon *s = opaque; 172 VirtIODevice *vdev = VIRTIO_DEVICE(s); 173 174 if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) { 175 /* re-schedule */ 176 balloon_stats_change_timer(s, s->stats_poll_interval); 177 return; 178 } 179 180 virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset); 181 virtio_notify(vdev, s->svq); 182 g_free(s->stats_vq_elem); 183 s->stats_vq_elem = NULL; 184 } 185 186 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name, 187 void *opaque, Error **errp) 188 { 189 Error *err = NULL; 190 VirtIOBalloon *s = opaque; 191 int i; 192 193 visit_start_struct(v, name, NULL, 0, &err); 194 if (err) { 195 goto out; 196 } 197 visit_type_int(v, "last-update", &s->stats_last_update, &err); 198 if (err) { 199 goto out_end; 200 } 201 202 visit_start_struct(v, "stats", NULL, 0, &err); 203 if (err) { 204 goto out_end; 205 } 206 for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) { 207 visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err); 208 if (err) { 209 goto out_nested; 210 } 211 } 212 visit_check_struct(v, &err); 213 out_nested: 214 visit_end_struct(v, NULL); 215 216 if (!err) { 217 visit_check_struct(v, &err); 218 } 219 out_end: 220 visit_end_struct(v, NULL); 221 out: 222 error_propagate(errp, err); 223 } 224 225 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v, 226 const char *name, void *opaque, 227 Error **errp) 228 { 229 VirtIOBalloon *s = opaque; 230 visit_type_int(v, name, &s->stats_poll_interval, errp); 231 } 232 233 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, 234 const char *name, void *opaque, 235 Error **errp) 236 { 237 VirtIOBalloon *s = opaque; 238 Error *local_err = NULL; 239 int64_t value; 240 241 visit_type_int(v, name, &value, &local_err); 242 if (local_err) { 243 error_propagate(errp, local_err); 244 return; 245 } 246 247 if (value < 0) { 248 error_setg(errp, "timer value must be greater than zero"); 249 return; 250 } 251 252 if (value > UINT32_MAX) { 253 error_setg(errp, "timer value is too big"); 254 return; 255 } 256 257 if (value == s->stats_poll_interval) { 258 return; 259 } 260 261 if (value == 0) { 262 /* timer=0 disables the timer */ 263 balloon_stats_destroy_timer(s); 264 return; 265 } 266 267 if (balloon_stats_enabled(s)) { 268 /* timer interval change */ 269 s->stats_poll_interval = value; 270 balloon_stats_change_timer(s, value); 271 return; 272 } 273 274 /* create a new timer */ 275 g_assert(s->stats_timer == NULL); 276 s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); 277 s->stats_poll_interval = value; 278 balloon_stats_change_timer(s, 0); 279 } 280 281 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 282 { 283 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 284 VirtQueueElement *elem; 285 MemoryRegionSection section; 286 287 for (;;) { 288 size_t offset = 0; 289 uint32_t pfn; 290 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 291 if (!elem) { 292 return; 293 } 294 295 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) { 296 hwaddr pa; 297 int p = virtio_ldl_p(vdev, &pfn); 298 299 pa = (hwaddr) p << VIRTIO_BALLOON_PFN_SHIFT; 300 offset += 4; 301 302 section = memory_region_find(get_system_memory(), pa, 303 BALLOON_PAGE_SIZE); 304 if (!section.mr) { 305 trace_virtio_balloon_bad_addr(pa); 306 continue; 307 } 308 if (!memory_region_is_ram(section.mr) || 309 memory_region_is_rom(section.mr) || 310 memory_region_is_romd(section.mr)) { 311 trace_virtio_balloon_bad_addr(pa); 312 memory_region_unref(section.mr); 313 continue; 314 } 315 316 trace_virtio_balloon_handle_output(memory_region_name(section.mr), 317 pa); 318 if (!qemu_balloon_is_inhibited() && vq != s->dvq) { 319 balloon_inflate_page(s, section.mr, section.offset_within_region); 320 } 321 memory_region_unref(section.mr); 322 } 323 324 virtqueue_push(vq, elem, offset); 325 virtio_notify(vdev, vq); 326 g_free(elem); 327 } 328 } 329 330 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) 331 { 332 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 333 VirtQueueElement *elem; 334 VirtIOBalloonStat stat; 335 size_t offset = 0; 336 qemu_timeval tv; 337 338 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 339 if (!elem) { 340 goto out; 341 } 342 343 if (s->stats_vq_elem != NULL) { 344 /* This should never happen if the driver follows the spec. */ 345 virtqueue_push(vq, s->stats_vq_elem, 0); 346 virtio_notify(vdev, vq); 347 g_free(s->stats_vq_elem); 348 } 349 350 s->stats_vq_elem = elem; 351 352 /* Initialize the stats to get rid of any stale values. This is only 353 * needed to handle the case where a guest supports fewer stats than it 354 * used to (ie. it has booted into an old kernel). 355 */ 356 reset_stats(s); 357 358 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) 359 == sizeof(stat)) { 360 uint16_t tag = virtio_tswap16(vdev, stat.tag); 361 uint64_t val = virtio_tswap64(vdev, stat.val); 362 363 offset += sizeof(stat); 364 if (tag < VIRTIO_BALLOON_S_NR) 365 s->stats[tag] = val; 366 } 367 s->stats_vq_offset = offset; 368 369 if (qemu_gettimeofday(&tv) < 0) { 370 warn_report("%s: failed to get time of day", __func__); 371 goto out; 372 } 373 374 s->stats_last_update = tv.tv_sec; 375 376 out: 377 if (balloon_stats_enabled(s)) { 378 balloon_stats_change_timer(s, s->stats_poll_interval); 379 } 380 } 381 382 static void virtio_balloon_handle_free_page_vq(VirtIODevice *vdev, 383 VirtQueue *vq) 384 { 385 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 386 qemu_bh_schedule(s->free_page_bh); 387 } 388 389 static bool get_free_page_hints(VirtIOBalloon *dev) 390 { 391 VirtQueueElement *elem; 392 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 393 VirtQueue *vq = dev->free_page_vq; 394 bool ret = true; 395 396 while (dev->block_iothread) { 397 qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock); 398 } 399 400 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 401 if (!elem) { 402 return false; 403 } 404 405 if (elem->out_num) { 406 uint32_t id; 407 size_t size = iov_to_buf(elem->out_sg, elem->out_num, 0, 408 &id, sizeof(id)); 409 410 virtio_tswap32s(vdev, &id); 411 if (unlikely(size != sizeof(id))) { 412 virtio_error(vdev, "received an incorrect cmd id"); 413 ret = false; 414 goto out; 415 } 416 if (id == dev->free_page_report_cmd_id) { 417 dev->free_page_report_status = FREE_PAGE_REPORT_S_START; 418 } else { 419 /* 420 * Stop the optimization only when it has started. This 421 * avoids a stale stop sign for the previous command. 422 */ 423 if (dev->free_page_report_status == FREE_PAGE_REPORT_S_START) { 424 dev->free_page_report_status = FREE_PAGE_REPORT_S_STOP; 425 } 426 } 427 } 428 429 if (elem->in_num) { 430 if (dev->free_page_report_status == FREE_PAGE_REPORT_S_START) { 431 qemu_guest_free_page_hint(elem->in_sg[0].iov_base, 432 elem->in_sg[0].iov_len); 433 } 434 } 435 436 out: 437 virtqueue_push(vq, elem, 1); 438 g_free(elem); 439 return ret; 440 } 441 442 static void virtio_ballloon_get_free_page_hints(void *opaque) 443 { 444 VirtIOBalloon *dev = opaque; 445 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 446 VirtQueue *vq = dev->free_page_vq; 447 bool continue_to_get_hints; 448 449 do { 450 qemu_mutex_lock(&dev->free_page_lock); 451 virtio_queue_set_notification(vq, 0); 452 continue_to_get_hints = get_free_page_hints(dev); 453 qemu_mutex_unlock(&dev->free_page_lock); 454 virtio_notify(vdev, vq); 455 /* 456 * Start to poll the vq once the reporting started. Otherwise, continue 457 * only when there are entries on the vq, which need to be given back. 458 */ 459 } while (continue_to_get_hints || 460 dev->free_page_report_status == FREE_PAGE_REPORT_S_START); 461 virtio_queue_set_notification(vq, 1); 462 } 463 464 static bool virtio_balloon_free_page_support(void *opaque) 465 { 466 VirtIOBalloon *s = opaque; 467 VirtIODevice *vdev = VIRTIO_DEVICE(s); 468 469 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT); 470 } 471 472 static void virtio_balloon_free_page_start(VirtIOBalloon *s) 473 { 474 VirtIODevice *vdev = VIRTIO_DEVICE(s); 475 476 /* For the stop and copy phase, we don't need to start the optimization */ 477 if (!vdev->vm_running) { 478 return; 479 } 480 481 if (s->free_page_report_cmd_id == UINT_MAX) { 482 s->free_page_report_cmd_id = 483 VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN; 484 } else { 485 s->free_page_report_cmd_id++; 486 } 487 488 s->free_page_report_status = FREE_PAGE_REPORT_S_REQUESTED; 489 virtio_notify_config(vdev); 490 } 491 492 static void virtio_balloon_free_page_stop(VirtIOBalloon *s) 493 { 494 VirtIODevice *vdev = VIRTIO_DEVICE(s); 495 496 if (s->free_page_report_status != FREE_PAGE_REPORT_S_STOP) { 497 /* 498 * The lock also guarantees us that the 499 * virtio_ballloon_get_free_page_hints exits after the 500 * free_page_report_status is set to S_STOP. 501 */ 502 qemu_mutex_lock(&s->free_page_lock); 503 /* 504 * The guest hasn't done the reporting, so host sends a notification 505 * to the guest to actively stop the reporting. 506 */ 507 s->free_page_report_status = FREE_PAGE_REPORT_S_STOP; 508 qemu_mutex_unlock(&s->free_page_lock); 509 virtio_notify_config(vdev); 510 } 511 } 512 513 static void virtio_balloon_free_page_done(VirtIOBalloon *s) 514 { 515 VirtIODevice *vdev = VIRTIO_DEVICE(s); 516 517 s->free_page_report_status = FREE_PAGE_REPORT_S_DONE; 518 virtio_notify_config(vdev); 519 } 520 521 static int 522 virtio_balloon_free_page_report_notify(NotifierWithReturn *n, void *data) 523 { 524 VirtIOBalloon *dev = container_of(n, VirtIOBalloon, 525 free_page_report_notify); 526 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 527 PrecopyNotifyData *pnd = data; 528 529 if (!virtio_balloon_free_page_support(dev)) { 530 /* 531 * This is an optimization provided to migration, so just return 0 to 532 * have the normal migration process not affected when this feature is 533 * not supported. 534 */ 535 return 0; 536 } 537 538 switch (pnd->reason) { 539 case PRECOPY_NOTIFY_SETUP: 540 precopy_enable_free_page_optimization(); 541 break; 542 case PRECOPY_NOTIFY_COMPLETE: 543 case PRECOPY_NOTIFY_CLEANUP: 544 case PRECOPY_NOTIFY_BEFORE_BITMAP_SYNC: 545 virtio_balloon_free_page_stop(dev); 546 break; 547 case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC: 548 if (vdev->vm_running) { 549 virtio_balloon_free_page_start(dev); 550 } else { 551 virtio_balloon_free_page_done(dev); 552 } 553 break; 554 default: 555 virtio_error(vdev, "%s: %d reason unknown", __func__, pnd->reason); 556 } 557 558 return 0; 559 } 560 561 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) 562 { 563 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 564 struct virtio_balloon_config config = {}; 565 566 config.num_pages = cpu_to_le32(dev->num_pages); 567 config.actual = cpu_to_le32(dev->actual); 568 569 if (dev->free_page_report_status == FREE_PAGE_REPORT_S_REQUESTED) { 570 config.free_page_report_cmd_id = 571 cpu_to_le32(dev->free_page_report_cmd_id); 572 } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_STOP) { 573 config.free_page_report_cmd_id = 574 cpu_to_le32(VIRTIO_BALLOON_CMD_ID_STOP); 575 } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_DONE) { 576 config.free_page_report_cmd_id = 577 cpu_to_le32(VIRTIO_BALLOON_CMD_ID_DONE); 578 } 579 580 trace_virtio_balloon_get_config(config.num_pages, config.actual); 581 memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); 582 } 583 584 static int build_dimm_list(Object *obj, void *opaque) 585 { 586 GSList **list = opaque; 587 588 if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { 589 DeviceState *dev = DEVICE(obj); 590 if (dev->realized) { /* only realized DIMMs matter */ 591 *list = g_slist_prepend(*list, dev); 592 } 593 } 594 595 object_child_foreach(obj, build_dimm_list, opaque); 596 return 0; 597 } 598 599 static ram_addr_t get_current_ram_size(void) 600 { 601 GSList *list = NULL, *item; 602 ram_addr_t size = ram_size; 603 604 build_dimm_list(qdev_get_machine(), &list); 605 for (item = list; item; item = g_slist_next(item)) { 606 Object *obj = OBJECT(item->data); 607 if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { 608 size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, 609 &error_abort); 610 } 611 } 612 g_slist_free(list); 613 614 return size; 615 } 616 617 static void virtio_balloon_set_config(VirtIODevice *vdev, 618 const uint8_t *config_data) 619 { 620 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 621 struct virtio_balloon_config config; 622 uint32_t oldactual = dev->actual; 623 ram_addr_t vm_ram_size = get_current_ram_size(); 624 625 memcpy(&config, config_data, sizeof(struct virtio_balloon_config)); 626 dev->actual = le32_to_cpu(config.actual); 627 if (dev->actual != oldactual) { 628 qapi_event_send_balloon_change(vm_ram_size - 629 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); 630 } 631 trace_virtio_balloon_set_config(dev->actual, oldactual); 632 } 633 634 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, 635 Error **errp) 636 { 637 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 638 f |= dev->host_features; 639 virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); 640 641 return f; 642 } 643 644 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 645 { 646 VirtIOBalloon *dev = opaque; 647 info->actual = get_current_ram_size() - ((uint64_t) dev->actual << 648 VIRTIO_BALLOON_PFN_SHIFT); 649 } 650 651 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 652 { 653 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 654 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 655 ram_addr_t vm_ram_size = get_current_ram_size(); 656 657 if (target > vm_ram_size) { 658 target = vm_ram_size; 659 } 660 if (target) { 661 dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 662 virtio_notify_config(vdev); 663 } 664 trace_virtio_balloon_to_target(target, dev->num_pages); 665 } 666 667 static int virtio_balloon_post_load_device(void *opaque, int version_id) 668 { 669 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 670 671 if (balloon_stats_enabled(s)) { 672 balloon_stats_change_timer(s, s->stats_poll_interval); 673 } 674 return 0; 675 } 676 677 static const VMStateDescription vmstate_virtio_balloon_free_page_report = { 678 .name = "virtio-balloon-device/free-page-report", 679 .version_id = 1, 680 .minimum_version_id = 1, 681 .needed = virtio_balloon_free_page_support, 682 .fields = (VMStateField[]) { 683 VMSTATE_UINT32(free_page_report_cmd_id, VirtIOBalloon), 684 VMSTATE_UINT32(free_page_report_status, VirtIOBalloon), 685 VMSTATE_END_OF_LIST() 686 } 687 }; 688 689 static const VMStateDescription vmstate_virtio_balloon_device = { 690 .name = "virtio-balloon-device", 691 .version_id = 1, 692 .minimum_version_id = 1, 693 .post_load = virtio_balloon_post_load_device, 694 .fields = (VMStateField[]) { 695 VMSTATE_UINT32(num_pages, VirtIOBalloon), 696 VMSTATE_UINT32(actual, VirtIOBalloon), 697 VMSTATE_END_OF_LIST() 698 }, 699 .subsections = (const VMStateDescription * []) { 700 &vmstate_virtio_balloon_free_page_report, 701 NULL 702 } 703 }; 704 705 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 706 { 707 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 708 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 709 int ret; 710 711 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 712 sizeof(struct virtio_balloon_config)); 713 714 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 715 virtio_balloon_stat, s); 716 717 if (ret < 0) { 718 error_setg(errp, "Only one balloon device is supported"); 719 virtio_cleanup(vdev); 720 return; 721 } 722 723 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 724 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 725 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 726 727 if (virtio_has_feature(s->host_features, 728 VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { 729 s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE, 730 virtio_balloon_handle_free_page_vq); 731 s->free_page_report_status = FREE_PAGE_REPORT_S_STOP; 732 s->free_page_report_cmd_id = 733 VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN; 734 s->free_page_report_notify.notify = 735 virtio_balloon_free_page_report_notify; 736 precopy_add_notifier(&s->free_page_report_notify); 737 if (s->iothread) { 738 object_ref(OBJECT(s->iothread)); 739 s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread), 740 virtio_ballloon_get_free_page_hints, s); 741 qemu_mutex_init(&s->free_page_lock); 742 qemu_cond_init(&s->free_page_cond); 743 s->block_iothread = false; 744 } else { 745 /* Simply disable this feature if the iothread wasn't created. */ 746 s->host_features &= ~(1 << VIRTIO_BALLOON_F_FREE_PAGE_HINT); 747 virtio_error(vdev, "iothread is missing"); 748 } 749 } 750 reset_stats(s); 751 } 752 753 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp) 754 { 755 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 756 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 757 758 if (virtio_balloon_free_page_support(s)) { 759 qemu_bh_delete(s->free_page_bh); 760 virtio_balloon_free_page_stop(s); 761 precopy_remove_notifier(&s->free_page_report_notify); 762 } 763 balloon_stats_destroy_timer(s); 764 qemu_remove_balloon_handler(s); 765 virtio_cleanup(vdev); 766 } 767 768 static void virtio_balloon_device_reset(VirtIODevice *vdev) 769 { 770 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 771 772 if (virtio_balloon_free_page_support(s)) { 773 virtio_balloon_free_page_stop(s); 774 } 775 776 if (s->stats_vq_elem != NULL) { 777 virtqueue_unpop(s->svq, s->stats_vq_elem, 0); 778 g_free(s->stats_vq_elem); 779 s->stats_vq_elem = NULL; 780 } 781 } 782 783 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status) 784 { 785 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 786 787 if (!s->stats_vq_elem && vdev->vm_running && 788 (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) { 789 /* poll stats queue for the element we have discarded when the VM 790 * was stopped */ 791 virtio_balloon_receive_stats(vdev, s->svq); 792 } 793 794 if (virtio_balloon_free_page_support(s)) { 795 /* 796 * The VM is woken up and the iothread was blocked, so signal it to 797 * continue. 798 */ 799 if (vdev->vm_running && s->block_iothread) { 800 qemu_mutex_lock(&s->free_page_lock); 801 s->block_iothread = false; 802 qemu_cond_signal(&s->free_page_cond); 803 qemu_mutex_unlock(&s->free_page_lock); 804 } 805 806 /* The VM is stopped, block the iothread. */ 807 if (!vdev->vm_running) { 808 qemu_mutex_lock(&s->free_page_lock); 809 s->block_iothread = true; 810 qemu_mutex_unlock(&s->free_page_lock); 811 } 812 } 813 } 814 815 static void virtio_balloon_instance_init(Object *obj) 816 { 817 VirtIOBalloon *s = VIRTIO_BALLOON(obj); 818 819 object_property_add(obj, "guest-stats", "guest statistics", 820 balloon_stats_get_all, NULL, NULL, s, NULL); 821 822 object_property_add(obj, "guest-stats-polling-interval", "int", 823 balloon_stats_get_poll_interval, 824 balloon_stats_set_poll_interval, 825 NULL, s, NULL); 826 } 827 828 static const VMStateDescription vmstate_virtio_balloon = { 829 .name = "virtio-balloon", 830 .minimum_version_id = 1, 831 .version_id = 1, 832 .fields = (VMStateField[]) { 833 VMSTATE_VIRTIO_DEVICE, 834 VMSTATE_END_OF_LIST() 835 }, 836 }; 837 838 static Property virtio_balloon_properties[] = { 839 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features, 840 VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), 841 DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features, 842 VIRTIO_BALLOON_F_FREE_PAGE_HINT, false), 843 DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD, 844 IOThread *), 845 DEFINE_PROP_END_OF_LIST(), 846 }; 847 848 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 849 { 850 DeviceClass *dc = DEVICE_CLASS(klass); 851 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 852 853 dc->props = virtio_balloon_properties; 854 dc->vmsd = &vmstate_virtio_balloon; 855 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 856 vdc->realize = virtio_balloon_device_realize; 857 vdc->unrealize = virtio_balloon_device_unrealize; 858 vdc->reset = virtio_balloon_device_reset; 859 vdc->get_config = virtio_balloon_get_config; 860 vdc->set_config = virtio_balloon_set_config; 861 vdc->get_features = virtio_balloon_get_features; 862 vdc->set_status = virtio_balloon_set_status; 863 vdc->vmsd = &vmstate_virtio_balloon_device; 864 } 865 866 static const TypeInfo virtio_balloon_info = { 867 .name = TYPE_VIRTIO_BALLOON, 868 .parent = TYPE_VIRTIO_DEVICE, 869 .instance_size = sizeof(VirtIOBalloon), 870 .instance_init = virtio_balloon_instance_init, 871 .class_init = virtio_balloon_class_init, 872 }; 873 874 static void virtio_register_types(void) 875 { 876 type_register_static(&virtio_balloon_info); 877 } 878 879 type_init(virtio_register_types) 880