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/module.h" 19 #include "qemu/timer.h" 20 #include "hw/virtio/virtio.h" 21 #include "hw/mem/pc-dimm.h" 22 #include "hw/qdev-properties.h" 23 #include "sysemu/balloon.h" 24 #include "hw/virtio/virtio-balloon.h" 25 #include "exec/address-spaces.h" 26 #include "qapi/error.h" 27 #include "qapi/qapi-events-misc.h" 28 #include "qapi/visitor.h" 29 #include "trace.h" 30 #include "qemu/error-report.h" 31 #include "migration/misc.h" 32 33 #include "hw/virtio/virtio-bus.h" 34 #include "hw/virtio/virtio-access.h" 35 36 #define BALLOON_PAGE_SIZE (1 << VIRTIO_BALLOON_PFN_SHIFT) 37 38 typedef struct PartiallyBalloonedPage { 39 ram_addr_t base_gpa; 40 unsigned long *bitmap; 41 } PartiallyBalloonedPage; 42 43 static void virtio_balloon_pbp_free(PartiallyBalloonedPage *pbp) 44 { 45 if (!pbp->bitmap) { 46 return; 47 } 48 g_free(pbp->bitmap); 49 pbp->bitmap = NULL; 50 } 51 52 static void virtio_balloon_pbp_alloc(PartiallyBalloonedPage *pbp, 53 ram_addr_t base_gpa, 54 long subpages) 55 { 56 pbp->base_gpa = base_gpa; 57 pbp->bitmap = bitmap_new(subpages); 58 } 59 60 static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp, 61 ram_addr_t base_gpa) 62 { 63 return pbp->base_gpa == base_gpa; 64 } 65 66 static void balloon_inflate_page(VirtIOBalloon *balloon, 67 MemoryRegion *mr, hwaddr mr_offset, 68 PartiallyBalloonedPage *pbp) 69 { 70 void *addr = memory_region_get_ram_ptr(mr) + mr_offset; 71 ram_addr_t rb_offset, rb_aligned_offset, base_gpa; 72 RAMBlock *rb; 73 size_t rb_page_size; 74 int subpages; 75 76 /* XXX is there a better way to get to the RAMBlock than via a 77 * host address? */ 78 rb = qemu_ram_block_from_host(addr, false, &rb_offset); 79 rb_page_size = qemu_ram_pagesize(rb); 80 81 if (rb_page_size == BALLOON_PAGE_SIZE) { 82 /* Easy case */ 83 84 ram_block_discard_range(rb, rb_offset, rb_page_size); 85 /* We ignore errors from ram_block_discard_range(), because it 86 * has already reported them, and failing to discard a balloon 87 * page is not fatal */ 88 return; 89 } 90 91 /* Hard case 92 * 93 * We've put a piece of a larger host page into the balloon - we 94 * need to keep track until we have a whole host page to 95 * discard 96 */ 97 warn_report_once( 98 "Balloon used with backing page size > 4kiB, this may not be reliable"); 99 100 rb_aligned_offset = QEMU_ALIGN_DOWN(rb_offset, rb_page_size); 101 subpages = rb_page_size / BALLOON_PAGE_SIZE; 102 base_gpa = memory_region_get_ram_addr(mr) + mr_offset - 103 (rb_offset - rb_aligned_offset); 104 105 if (pbp->bitmap && !virtio_balloon_pbp_matches(pbp, base_gpa)) { 106 /* We've partially ballooned part of a host page, but now 107 * we're trying to balloon part of a different one. Too hard, 108 * give up on the old partial page */ 109 virtio_balloon_pbp_free(pbp); 110 } 111 112 if (!pbp->bitmap) { 113 virtio_balloon_pbp_alloc(pbp, base_gpa, subpages); 114 } 115 116 set_bit((rb_offset - rb_aligned_offset) / BALLOON_PAGE_SIZE, 117 pbp->bitmap); 118 119 if (bitmap_full(pbp->bitmap, subpages)) { 120 /* We've accumulated a full host page, we can actually discard 121 * it now */ 122 123 ram_block_discard_range(rb, rb_aligned_offset, rb_page_size); 124 /* We ignore errors from ram_block_discard_range(), because it 125 * has already reported them, and failing to discard a balloon 126 * page is not fatal */ 127 virtio_balloon_pbp_free(pbp); 128 } 129 } 130 131 static void balloon_deflate_page(VirtIOBalloon *balloon, 132 MemoryRegion *mr, hwaddr mr_offset) 133 { 134 void *addr = memory_region_get_ram_ptr(mr) + mr_offset; 135 ram_addr_t rb_offset; 136 RAMBlock *rb; 137 size_t rb_page_size; 138 void *host_addr; 139 int ret; 140 141 /* XXX is there a better way to get to the RAMBlock than via a 142 * host address? */ 143 rb = qemu_ram_block_from_host(addr, false, &rb_offset); 144 rb_page_size = qemu_ram_pagesize(rb); 145 146 host_addr = (void *)((uintptr_t)addr & ~(rb_page_size - 1)); 147 148 /* When a page is deflated, we hint the whole host page it lives 149 * on, since we can't do anything smaller */ 150 ret = qemu_madvise(host_addr, rb_page_size, QEMU_MADV_WILLNEED); 151 if (ret != 0) { 152 warn_report("Couldn't MADV_WILLNEED on balloon deflate: %s", 153 strerror(errno)); 154 /* Otherwise ignore, failing to page hint shouldn't be fatal */ 155 } 156 } 157 158 static const char *balloon_stat_names[] = { 159 [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", 160 [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", 161 [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", 162 [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", 163 [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", 164 [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", 165 [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory", 166 [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches", 167 [VIRTIO_BALLOON_S_HTLB_PGALLOC] = "stat-htlb-pgalloc", 168 [VIRTIO_BALLOON_S_HTLB_PGFAIL] = "stat-htlb-pgfail", 169 [VIRTIO_BALLOON_S_NR] = NULL 170 }; 171 172 /* 173 * reset_stats - Mark all items in the stats array as unset 174 * 175 * This function needs to be called at device initialization and before 176 * updating to a set of newly-generated stats. This will ensure that no 177 * stale values stick around in case the guest reports a subset of the supported 178 * statistics. 179 */ 180 static inline void reset_stats(VirtIOBalloon *dev) 181 { 182 int i; 183 for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); 184 } 185 186 static bool balloon_stats_supported(const VirtIOBalloon *s) 187 { 188 VirtIODevice *vdev = VIRTIO_DEVICE(s); 189 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); 190 } 191 192 static bool balloon_stats_enabled(const VirtIOBalloon *s) 193 { 194 return s->stats_poll_interval > 0; 195 } 196 197 static void balloon_stats_destroy_timer(VirtIOBalloon *s) 198 { 199 if (balloon_stats_enabled(s)) { 200 timer_del(s->stats_timer); 201 timer_free(s->stats_timer); 202 s->stats_timer = NULL; 203 s->stats_poll_interval = 0; 204 } 205 } 206 207 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs) 208 { 209 timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); 210 } 211 212 static void balloon_stats_poll_cb(void *opaque) 213 { 214 VirtIOBalloon *s = opaque; 215 VirtIODevice *vdev = VIRTIO_DEVICE(s); 216 217 if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) { 218 /* re-schedule */ 219 balloon_stats_change_timer(s, s->stats_poll_interval); 220 return; 221 } 222 223 virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset); 224 virtio_notify(vdev, s->svq); 225 g_free(s->stats_vq_elem); 226 s->stats_vq_elem = NULL; 227 } 228 229 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name, 230 void *opaque, Error **errp) 231 { 232 Error *err = NULL; 233 VirtIOBalloon *s = opaque; 234 int i; 235 236 visit_start_struct(v, name, NULL, 0, &err); 237 if (err) { 238 goto out; 239 } 240 visit_type_int(v, "last-update", &s->stats_last_update, &err); 241 if (err) { 242 goto out_end; 243 } 244 245 visit_start_struct(v, "stats", NULL, 0, &err); 246 if (err) { 247 goto out_end; 248 } 249 for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) { 250 visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err); 251 if (err) { 252 goto out_nested; 253 } 254 } 255 visit_check_struct(v, &err); 256 out_nested: 257 visit_end_struct(v, NULL); 258 259 if (!err) { 260 visit_check_struct(v, &err); 261 } 262 out_end: 263 visit_end_struct(v, NULL); 264 out: 265 error_propagate(errp, err); 266 } 267 268 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v, 269 const char *name, void *opaque, 270 Error **errp) 271 { 272 VirtIOBalloon *s = opaque; 273 visit_type_int(v, name, &s->stats_poll_interval, errp); 274 } 275 276 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v, 277 const char *name, void *opaque, 278 Error **errp) 279 { 280 VirtIOBalloon *s = opaque; 281 Error *local_err = NULL; 282 int64_t value; 283 284 visit_type_int(v, name, &value, &local_err); 285 if (local_err) { 286 error_propagate(errp, local_err); 287 return; 288 } 289 290 if (value < 0) { 291 error_setg(errp, "timer value must be greater than zero"); 292 return; 293 } 294 295 if (value > UINT32_MAX) { 296 error_setg(errp, "timer value is too big"); 297 return; 298 } 299 300 if (value == s->stats_poll_interval) { 301 return; 302 } 303 304 if (value == 0) { 305 /* timer=0 disables the timer */ 306 balloon_stats_destroy_timer(s); 307 return; 308 } 309 310 if (balloon_stats_enabled(s)) { 311 /* timer interval change */ 312 s->stats_poll_interval = value; 313 balloon_stats_change_timer(s, value); 314 return; 315 } 316 317 /* create a new timer */ 318 g_assert(s->stats_timer == NULL); 319 s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); 320 s->stats_poll_interval = value; 321 balloon_stats_change_timer(s, 0); 322 } 323 324 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 325 { 326 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 327 VirtQueueElement *elem; 328 MemoryRegionSection section; 329 330 for (;;) { 331 PartiallyBalloonedPage pbp = {}; 332 size_t offset = 0; 333 uint32_t pfn; 334 335 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 336 if (!elem) { 337 break; 338 } 339 340 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) { 341 unsigned int p = virtio_ldl_p(vdev, &pfn); 342 hwaddr pa; 343 344 pa = (hwaddr) p << VIRTIO_BALLOON_PFN_SHIFT; 345 offset += 4; 346 347 section = memory_region_find(get_system_memory(), pa, 348 BALLOON_PAGE_SIZE); 349 if (!section.mr) { 350 trace_virtio_balloon_bad_addr(pa); 351 continue; 352 } 353 if (!memory_region_is_ram(section.mr) || 354 memory_region_is_rom(section.mr) || 355 memory_region_is_romd(section.mr)) { 356 trace_virtio_balloon_bad_addr(pa); 357 memory_region_unref(section.mr); 358 continue; 359 } 360 361 trace_virtio_balloon_handle_output(memory_region_name(section.mr), 362 pa); 363 if (!qemu_balloon_is_inhibited()) { 364 if (vq == s->ivq) { 365 balloon_inflate_page(s, section.mr, 366 section.offset_within_region, &pbp); 367 } else if (vq == s->dvq) { 368 balloon_deflate_page(s, section.mr, section.offset_within_region); 369 } else { 370 g_assert_not_reached(); 371 } 372 } 373 memory_region_unref(section.mr); 374 } 375 376 virtqueue_push(vq, elem, offset); 377 virtio_notify(vdev, vq); 378 g_free(elem); 379 virtio_balloon_pbp_free(&pbp); 380 } 381 } 382 383 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) 384 { 385 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 386 VirtQueueElement *elem; 387 VirtIOBalloonStat stat; 388 size_t offset = 0; 389 qemu_timeval tv; 390 391 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 392 if (!elem) { 393 goto out; 394 } 395 396 if (s->stats_vq_elem != NULL) { 397 /* This should never happen if the driver follows the spec. */ 398 virtqueue_push(vq, s->stats_vq_elem, 0); 399 virtio_notify(vdev, vq); 400 g_free(s->stats_vq_elem); 401 } 402 403 s->stats_vq_elem = elem; 404 405 /* Initialize the stats to get rid of any stale values. This is only 406 * needed to handle the case where a guest supports fewer stats than it 407 * used to (ie. it has booted into an old kernel). 408 */ 409 reset_stats(s); 410 411 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) 412 == sizeof(stat)) { 413 uint16_t tag = virtio_tswap16(vdev, stat.tag); 414 uint64_t val = virtio_tswap64(vdev, stat.val); 415 416 offset += sizeof(stat); 417 if (tag < VIRTIO_BALLOON_S_NR) 418 s->stats[tag] = val; 419 } 420 s->stats_vq_offset = offset; 421 422 if (qemu_gettimeofday(&tv) < 0) { 423 warn_report("%s: failed to get time of day", __func__); 424 goto out; 425 } 426 427 s->stats_last_update = tv.tv_sec; 428 429 out: 430 if (balloon_stats_enabled(s)) { 431 balloon_stats_change_timer(s, s->stats_poll_interval); 432 } 433 } 434 435 static void virtio_balloon_handle_free_page_vq(VirtIODevice *vdev, 436 VirtQueue *vq) 437 { 438 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 439 qemu_bh_schedule(s->free_page_bh); 440 } 441 442 static bool get_free_page_hints(VirtIOBalloon *dev) 443 { 444 VirtQueueElement *elem; 445 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 446 VirtQueue *vq = dev->free_page_vq; 447 bool ret = true; 448 449 while (dev->block_iothread) { 450 qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock); 451 } 452 453 elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); 454 if (!elem) { 455 return false; 456 } 457 458 if (elem->out_num) { 459 uint32_t id; 460 size_t size = iov_to_buf(elem->out_sg, elem->out_num, 0, 461 &id, sizeof(id)); 462 463 virtio_tswap32s(vdev, &id); 464 if (unlikely(size != sizeof(id))) { 465 virtio_error(vdev, "received an incorrect cmd id"); 466 ret = false; 467 goto out; 468 } 469 if (id == dev->free_page_report_cmd_id) { 470 dev->free_page_report_status = FREE_PAGE_REPORT_S_START; 471 } else { 472 /* 473 * Stop the optimization only when it has started. This 474 * avoids a stale stop sign for the previous command. 475 */ 476 if (dev->free_page_report_status == FREE_PAGE_REPORT_S_START) { 477 dev->free_page_report_status = FREE_PAGE_REPORT_S_STOP; 478 } 479 } 480 } 481 482 if (elem->in_num) { 483 if (dev->free_page_report_status == FREE_PAGE_REPORT_S_START) { 484 qemu_guest_free_page_hint(elem->in_sg[0].iov_base, 485 elem->in_sg[0].iov_len); 486 } 487 } 488 489 out: 490 virtqueue_push(vq, elem, 1); 491 g_free(elem); 492 return ret; 493 } 494 495 static void virtio_ballloon_get_free_page_hints(void *opaque) 496 { 497 VirtIOBalloon *dev = opaque; 498 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 499 VirtQueue *vq = dev->free_page_vq; 500 bool continue_to_get_hints; 501 502 do { 503 qemu_mutex_lock(&dev->free_page_lock); 504 virtio_queue_set_notification(vq, 0); 505 continue_to_get_hints = get_free_page_hints(dev); 506 qemu_mutex_unlock(&dev->free_page_lock); 507 virtio_notify(vdev, vq); 508 /* 509 * Start to poll the vq once the reporting started. Otherwise, continue 510 * only when there are entries on the vq, which need to be given back. 511 */ 512 } while (continue_to_get_hints || 513 dev->free_page_report_status == FREE_PAGE_REPORT_S_START); 514 virtio_queue_set_notification(vq, 1); 515 } 516 517 static bool virtio_balloon_free_page_support(void *opaque) 518 { 519 VirtIOBalloon *s = opaque; 520 VirtIODevice *vdev = VIRTIO_DEVICE(s); 521 522 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT); 523 } 524 525 static void virtio_balloon_free_page_start(VirtIOBalloon *s) 526 { 527 VirtIODevice *vdev = VIRTIO_DEVICE(s); 528 529 /* For the stop and copy phase, we don't need to start the optimization */ 530 if (!vdev->vm_running) { 531 return; 532 } 533 534 if (s->free_page_report_cmd_id == UINT_MAX) { 535 s->free_page_report_cmd_id = 536 VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN; 537 } else { 538 s->free_page_report_cmd_id++; 539 } 540 541 s->free_page_report_status = FREE_PAGE_REPORT_S_REQUESTED; 542 virtio_notify_config(vdev); 543 } 544 545 static void virtio_balloon_free_page_stop(VirtIOBalloon *s) 546 { 547 VirtIODevice *vdev = VIRTIO_DEVICE(s); 548 549 if (s->free_page_report_status != FREE_PAGE_REPORT_S_STOP) { 550 /* 551 * The lock also guarantees us that the 552 * virtio_ballloon_get_free_page_hints exits after the 553 * free_page_report_status is set to S_STOP. 554 */ 555 qemu_mutex_lock(&s->free_page_lock); 556 /* 557 * The guest hasn't done the reporting, so host sends a notification 558 * to the guest to actively stop the reporting. 559 */ 560 s->free_page_report_status = FREE_PAGE_REPORT_S_STOP; 561 qemu_mutex_unlock(&s->free_page_lock); 562 virtio_notify_config(vdev); 563 } 564 } 565 566 static void virtio_balloon_free_page_done(VirtIOBalloon *s) 567 { 568 VirtIODevice *vdev = VIRTIO_DEVICE(s); 569 570 s->free_page_report_status = FREE_PAGE_REPORT_S_DONE; 571 virtio_notify_config(vdev); 572 } 573 574 static int 575 virtio_balloon_free_page_report_notify(NotifierWithReturn *n, void *data) 576 { 577 VirtIOBalloon *dev = container_of(n, VirtIOBalloon, 578 free_page_report_notify); 579 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 580 PrecopyNotifyData *pnd = data; 581 582 if (!virtio_balloon_free_page_support(dev)) { 583 /* 584 * This is an optimization provided to migration, so just return 0 to 585 * have the normal migration process not affected when this feature is 586 * not supported. 587 */ 588 return 0; 589 } 590 591 switch (pnd->reason) { 592 case PRECOPY_NOTIFY_SETUP: 593 precopy_enable_free_page_optimization(); 594 break; 595 case PRECOPY_NOTIFY_COMPLETE: 596 case PRECOPY_NOTIFY_CLEANUP: 597 case PRECOPY_NOTIFY_BEFORE_BITMAP_SYNC: 598 virtio_balloon_free_page_stop(dev); 599 break; 600 case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC: 601 if (vdev->vm_running) { 602 virtio_balloon_free_page_start(dev); 603 } else { 604 virtio_balloon_free_page_done(dev); 605 } 606 break; 607 default: 608 virtio_error(vdev, "%s: %d reason unknown", __func__, pnd->reason); 609 } 610 611 return 0; 612 } 613 614 static size_t virtio_balloon_config_size(VirtIOBalloon *s) 615 { 616 uint64_t features = s->host_features; 617 618 if (s->qemu_4_0_config_size) { 619 return sizeof(struct virtio_balloon_config); 620 } 621 if (virtio_has_feature(features, VIRTIO_BALLOON_F_PAGE_POISON)) { 622 return sizeof(struct virtio_balloon_config); 623 } 624 if (virtio_has_feature(features, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { 625 return offsetof(struct virtio_balloon_config, poison_val); 626 } 627 return offsetof(struct virtio_balloon_config, free_page_report_cmd_id); 628 } 629 630 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) 631 { 632 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 633 struct virtio_balloon_config config = {}; 634 635 config.num_pages = cpu_to_le32(dev->num_pages); 636 config.actual = cpu_to_le32(dev->actual); 637 638 if (dev->free_page_report_status == FREE_PAGE_REPORT_S_REQUESTED) { 639 config.free_page_report_cmd_id = 640 cpu_to_le32(dev->free_page_report_cmd_id); 641 } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_STOP) { 642 config.free_page_report_cmd_id = 643 cpu_to_le32(VIRTIO_BALLOON_CMD_ID_STOP); 644 } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_DONE) { 645 config.free_page_report_cmd_id = 646 cpu_to_le32(VIRTIO_BALLOON_CMD_ID_DONE); 647 } 648 649 trace_virtio_balloon_get_config(config.num_pages, config.actual); 650 memcpy(config_data, &config, virtio_balloon_config_size(dev)); 651 } 652 653 static int build_dimm_list(Object *obj, void *opaque) 654 { 655 GSList **list = opaque; 656 657 if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { 658 DeviceState *dev = DEVICE(obj); 659 if (dev->realized) { /* only realized DIMMs matter */ 660 *list = g_slist_prepend(*list, dev); 661 } 662 } 663 664 object_child_foreach(obj, build_dimm_list, opaque); 665 return 0; 666 } 667 668 static ram_addr_t get_current_ram_size(void) 669 { 670 GSList *list = NULL, *item; 671 ram_addr_t size = ram_size; 672 673 build_dimm_list(qdev_get_machine(), &list); 674 for (item = list; item; item = g_slist_next(item)) { 675 Object *obj = OBJECT(item->data); 676 if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { 677 size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, 678 &error_abort); 679 } 680 } 681 g_slist_free(list); 682 683 return size; 684 } 685 686 static void virtio_balloon_set_config(VirtIODevice *vdev, 687 const uint8_t *config_data) 688 { 689 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 690 struct virtio_balloon_config config; 691 uint32_t oldactual = dev->actual; 692 ram_addr_t vm_ram_size = get_current_ram_size(); 693 694 memcpy(&config, config_data, virtio_balloon_config_size(dev)); 695 dev->actual = le32_to_cpu(config.actual); 696 if (dev->actual != oldactual) { 697 qapi_event_send_balloon_change(vm_ram_size - 698 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); 699 } 700 trace_virtio_balloon_set_config(dev->actual, oldactual); 701 } 702 703 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, 704 Error **errp) 705 { 706 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 707 f |= dev->host_features; 708 virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); 709 710 return f; 711 } 712 713 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 714 { 715 VirtIOBalloon *dev = opaque; 716 info->actual = get_current_ram_size() - ((uint64_t) dev->actual << 717 VIRTIO_BALLOON_PFN_SHIFT); 718 } 719 720 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 721 { 722 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 723 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 724 ram_addr_t vm_ram_size = get_current_ram_size(); 725 726 if (target > vm_ram_size) { 727 target = vm_ram_size; 728 } 729 if (target) { 730 dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 731 virtio_notify_config(vdev); 732 } 733 trace_virtio_balloon_to_target(target, dev->num_pages); 734 } 735 736 static int virtio_balloon_post_load_device(void *opaque, int version_id) 737 { 738 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 739 740 if (balloon_stats_enabled(s)) { 741 balloon_stats_change_timer(s, s->stats_poll_interval); 742 } 743 return 0; 744 } 745 746 static const VMStateDescription vmstate_virtio_balloon_free_page_report = { 747 .name = "virtio-balloon-device/free-page-report", 748 .version_id = 1, 749 .minimum_version_id = 1, 750 .needed = virtio_balloon_free_page_support, 751 .fields = (VMStateField[]) { 752 VMSTATE_UINT32(free_page_report_cmd_id, VirtIOBalloon), 753 VMSTATE_UINT32(free_page_report_status, VirtIOBalloon), 754 VMSTATE_END_OF_LIST() 755 } 756 }; 757 758 static const VMStateDescription vmstate_virtio_balloon_device = { 759 .name = "virtio-balloon-device", 760 .version_id = 1, 761 .minimum_version_id = 1, 762 .post_load = virtio_balloon_post_load_device, 763 .fields = (VMStateField[]) { 764 VMSTATE_UINT32(num_pages, VirtIOBalloon), 765 VMSTATE_UINT32(actual, VirtIOBalloon), 766 VMSTATE_END_OF_LIST() 767 }, 768 .subsections = (const VMStateDescription * []) { 769 &vmstate_virtio_balloon_free_page_report, 770 NULL 771 } 772 }; 773 774 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 775 { 776 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 777 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 778 int ret; 779 780 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 781 virtio_balloon_config_size(s)); 782 783 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 784 virtio_balloon_stat, s); 785 786 if (ret < 0) { 787 error_setg(errp, "Only one balloon device is supported"); 788 virtio_cleanup(vdev); 789 return; 790 } 791 792 if (virtio_has_feature(s->host_features, VIRTIO_BALLOON_F_FREE_PAGE_HINT) && 793 !s->iothread) { 794 error_setg(errp, "'free-page-hint' requires 'iothread' to be set"); 795 virtio_cleanup(vdev); 796 return; 797 } 798 799 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 800 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 801 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 802 803 if (virtio_has_feature(s->host_features, 804 VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { 805 s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE, 806 virtio_balloon_handle_free_page_vq); 807 precopy_add_notifier(&s->free_page_report_notify); 808 809 object_ref(OBJECT(s->iothread)); 810 s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread), 811 virtio_ballloon_get_free_page_hints, s); 812 } 813 reset_stats(s); 814 } 815 816 static void virtio_balloon_device_unrealize(DeviceState *dev) 817 { 818 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 819 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 820 821 if (s->free_page_bh) { 822 qemu_bh_delete(s->free_page_bh); 823 virtio_balloon_free_page_stop(s); 824 precopy_remove_notifier(&s->free_page_report_notify); 825 } 826 balloon_stats_destroy_timer(s); 827 qemu_remove_balloon_handler(s); 828 829 virtio_delete_queue(s->ivq); 830 virtio_delete_queue(s->dvq); 831 virtio_delete_queue(s->svq); 832 if (s->free_page_vq) { 833 virtio_delete_queue(s->free_page_vq); 834 } 835 virtio_cleanup(vdev); 836 } 837 838 static void virtio_balloon_device_reset(VirtIODevice *vdev) 839 { 840 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 841 842 if (virtio_balloon_free_page_support(s)) { 843 virtio_balloon_free_page_stop(s); 844 } 845 846 if (s->stats_vq_elem != NULL) { 847 virtqueue_unpop(s->svq, s->stats_vq_elem, 0); 848 g_free(s->stats_vq_elem); 849 s->stats_vq_elem = NULL; 850 } 851 } 852 853 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status) 854 { 855 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 856 857 if (!s->stats_vq_elem && vdev->vm_running && 858 (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) { 859 /* poll stats queue for the element we have discarded when the VM 860 * was stopped */ 861 virtio_balloon_receive_stats(vdev, s->svq); 862 } 863 864 if (virtio_balloon_free_page_support(s)) { 865 /* 866 * The VM is woken up and the iothread was blocked, so signal it to 867 * continue. 868 */ 869 if (vdev->vm_running && s->block_iothread) { 870 qemu_mutex_lock(&s->free_page_lock); 871 s->block_iothread = false; 872 qemu_cond_signal(&s->free_page_cond); 873 qemu_mutex_unlock(&s->free_page_lock); 874 } 875 876 /* The VM is stopped, block the iothread. */ 877 if (!vdev->vm_running) { 878 qemu_mutex_lock(&s->free_page_lock); 879 s->block_iothread = true; 880 qemu_mutex_unlock(&s->free_page_lock); 881 } 882 } 883 } 884 885 static void virtio_balloon_instance_init(Object *obj) 886 { 887 VirtIOBalloon *s = VIRTIO_BALLOON(obj); 888 889 qemu_mutex_init(&s->free_page_lock); 890 qemu_cond_init(&s->free_page_cond); 891 s->free_page_report_cmd_id = VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN; 892 s->free_page_report_notify.notify = virtio_balloon_free_page_report_notify; 893 894 object_property_add(obj, "guest-stats", "guest statistics", 895 balloon_stats_get_all, NULL, NULL, s); 896 897 object_property_add(obj, "guest-stats-polling-interval", "int", 898 balloon_stats_get_poll_interval, 899 balloon_stats_set_poll_interval, 900 NULL, s); 901 } 902 903 static const VMStateDescription vmstate_virtio_balloon = { 904 .name = "virtio-balloon", 905 .minimum_version_id = 1, 906 .version_id = 1, 907 .fields = (VMStateField[]) { 908 VMSTATE_VIRTIO_DEVICE, 909 VMSTATE_END_OF_LIST() 910 }, 911 }; 912 913 static Property virtio_balloon_properties[] = { 914 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features, 915 VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), 916 DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features, 917 VIRTIO_BALLOON_F_FREE_PAGE_HINT, false), 918 /* QEMU 4.0 accidentally changed the config size even when free-page-hint 919 * is disabled, resulting in QEMU 3.1 migration incompatibility. This 920 * property retains this quirk for QEMU 4.1 machine types. 921 */ 922 DEFINE_PROP_BOOL("qemu-4-0-config-size", VirtIOBalloon, 923 qemu_4_0_config_size, false), 924 DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD, 925 IOThread *), 926 DEFINE_PROP_END_OF_LIST(), 927 }; 928 929 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 930 { 931 DeviceClass *dc = DEVICE_CLASS(klass); 932 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 933 934 device_class_set_props(dc, virtio_balloon_properties); 935 dc->vmsd = &vmstate_virtio_balloon; 936 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 937 vdc->realize = virtio_balloon_device_realize; 938 vdc->unrealize = virtio_balloon_device_unrealize; 939 vdc->reset = virtio_balloon_device_reset; 940 vdc->get_config = virtio_balloon_get_config; 941 vdc->set_config = virtio_balloon_set_config; 942 vdc->get_features = virtio_balloon_get_features; 943 vdc->set_status = virtio_balloon_set_status; 944 vdc->vmsd = &vmstate_virtio_balloon_device; 945 } 946 947 static const TypeInfo virtio_balloon_info = { 948 .name = TYPE_VIRTIO_BALLOON, 949 .parent = TYPE_VIRTIO_DEVICE, 950 .instance_size = sizeof(VirtIOBalloon), 951 .instance_init = virtio_balloon_instance_init, 952 .class_init = virtio_balloon_class_init, 953 }; 954 955 static void virtio_register_types(void) 956 { 957 type_register_static(&virtio_balloon_info); 958 } 959 960 type_init(virtio_register_types) 961