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 config.poison_val = cpu_to_le32(dev->poison_val); 638 639 if (dev->free_page_report_status == FREE_PAGE_REPORT_S_REQUESTED) { 640 config.free_page_report_cmd_id = 641 cpu_to_le32(dev->free_page_report_cmd_id); 642 } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_STOP) { 643 config.free_page_report_cmd_id = 644 cpu_to_le32(VIRTIO_BALLOON_CMD_ID_STOP); 645 } else if (dev->free_page_report_status == FREE_PAGE_REPORT_S_DONE) { 646 config.free_page_report_cmd_id = 647 cpu_to_le32(VIRTIO_BALLOON_CMD_ID_DONE); 648 } 649 650 trace_virtio_balloon_get_config(config.num_pages, config.actual); 651 memcpy(config_data, &config, virtio_balloon_config_size(dev)); 652 } 653 654 static int build_dimm_list(Object *obj, void *opaque) 655 { 656 GSList **list = opaque; 657 658 if (object_dynamic_cast(obj, TYPE_PC_DIMM)) { 659 DeviceState *dev = DEVICE(obj); 660 if (dev->realized) { /* only realized DIMMs matter */ 661 *list = g_slist_prepend(*list, dev); 662 } 663 } 664 665 object_child_foreach(obj, build_dimm_list, opaque); 666 return 0; 667 } 668 669 static ram_addr_t get_current_ram_size(void) 670 { 671 GSList *list = NULL, *item; 672 ram_addr_t size = ram_size; 673 674 build_dimm_list(qdev_get_machine(), &list); 675 for (item = list; item; item = g_slist_next(item)) { 676 Object *obj = OBJECT(item->data); 677 if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) { 678 size += object_property_get_int(obj, PC_DIMM_SIZE_PROP, 679 &error_abort); 680 } 681 } 682 g_slist_free(list); 683 684 return size; 685 } 686 687 static bool virtio_balloon_page_poison_support(void *opaque) 688 { 689 VirtIOBalloon *s = opaque; 690 VirtIODevice *vdev = VIRTIO_DEVICE(s); 691 692 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON); 693 } 694 695 static void virtio_balloon_set_config(VirtIODevice *vdev, 696 const uint8_t *config_data) 697 { 698 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 699 struct virtio_balloon_config config; 700 uint32_t oldactual = dev->actual; 701 ram_addr_t vm_ram_size = get_current_ram_size(); 702 703 memcpy(&config, config_data, virtio_balloon_config_size(dev)); 704 dev->actual = le32_to_cpu(config.actual); 705 if (dev->actual != oldactual) { 706 qapi_event_send_balloon_change(vm_ram_size - 707 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); 708 } 709 dev->poison_val = 0; 710 if (virtio_balloon_page_poison_support(dev)) { 711 dev->poison_val = le32_to_cpu(config.poison_val); 712 } 713 trace_virtio_balloon_set_config(dev->actual, oldactual); 714 } 715 716 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, 717 Error **errp) 718 { 719 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 720 f |= dev->host_features; 721 virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); 722 723 return f; 724 } 725 726 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 727 { 728 VirtIOBalloon *dev = opaque; 729 info->actual = get_current_ram_size() - ((uint64_t) dev->actual << 730 VIRTIO_BALLOON_PFN_SHIFT); 731 } 732 733 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 734 { 735 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 736 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 737 ram_addr_t vm_ram_size = get_current_ram_size(); 738 739 if (target > vm_ram_size) { 740 target = vm_ram_size; 741 } 742 if (target) { 743 dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 744 virtio_notify_config(vdev); 745 } 746 trace_virtio_balloon_to_target(target, dev->num_pages); 747 } 748 749 static int virtio_balloon_post_load_device(void *opaque, int version_id) 750 { 751 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 752 753 if (balloon_stats_enabled(s)) { 754 balloon_stats_change_timer(s, s->stats_poll_interval); 755 } 756 return 0; 757 } 758 759 static const VMStateDescription vmstate_virtio_balloon_free_page_report = { 760 .name = "virtio-balloon-device/free-page-report", 761 .version_id = 1, 762 .minimum_version_id = 1, 763 .needed = virtio_balloon_free_page_support, 764 .fields = (VMStateField[]) { 765 VMSTATE_UINT32(free_page_report_cmd_id, VirtIOBalloon), 766 VMSTATE_UINT32(free_page_report_status, VirtIOBalloon), 767 VMSTATE_END_OF_LIST() 768 } 769 }; 770 771 static const VMStateDescription vmstate_virtio_balloon_page_poison = { 772 .name = "vitio-balloon-device/page-poison", 773 .version_id = 1, 774 .minimum_version_id = 1, 775 .needed = virtio_balloon_page_poison_support, 776 .fields = (VMStateField[]) { 777 VMSTATE_UINT32(poison_val, VirtIOBalloon), 778 VMSTATE_END_OF_LIST() 779 } 780 }; 781 782 static const VMStateDescription vmstate_virtio_balloon_device = { 783 .name = "virtio-balloon-device", 784 .version_id = 1, 785 .minimum_version_id = 1, 786 .post_load = virtio_balloon_post_load_device, 787 .fields = (VMStateField[]) { 788 VMSTATE_UINT32(num_pages, VirtIOBalloon), 789 VMSTATE_UINT32(actual, VirtIOBalloon), 790 VMSTATE_END_OF_LIST() 791 }, 792 .subsections = (const VMStateDescription * []) { 793 &vmstate_virtio_balloon_free_page_report, 794 &vmstate_virtio_balloon_page_poison, 795 NULL 796 } 797 }; 798 799 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 800 { 801 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 802 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 803 int ret; 804 805 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 806 virtio_balloon_config_size(s)); 807 808 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 809 virtio_balloon_stat, s); 810 811 if (ret < 0) { 812 error_setg(errp, "Only one balloon device is supported"); 813 virtio_cleanup(vdev); 814 return; 815 } 816 817 if (virtio_has_feature(s->host_features, VIRTIO_BALLOON_F_FREE_PAGE_HINT) && 818 !s->iothread) { 819 error_setg(errp, "'free-page-hint' requires 'iothread' to be set"); 820 virtio_cleanup(vdev); 821 return; 822 } 823 824 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 825 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 826 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 827 828 if (virtio_has_feature(s->host_features, 829 VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { 830 s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE, 831 virtio_balloon_handle_free_page_vq); 832 precopy_add_notifier(&s->free_page_report_notify); 833 834 object_ref(OBJECT(s->iothread)); 835 s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread), 836 virtio_ballloon_get_free_page_hints, s); 837 } 838 reset_stats(s); 839 } 840 841 static void virtio_balloon_device_unrealize(DeviceState *dev) 842 { 843 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 844 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 845 846 if (s->free_page_bh) { 847 qemu_bh_delete(s->free_page_bh); 848 object_unref(OBJECT(s->iothread)); 849 virtio_balloon_free_page_stop(s); 850 precopy_remove_notifier(&s->free_page_report_notify); 851 } 852 balloon_stats_destroy_timer(s); 853 qemu_remove_balloon_handler(s); 854 855 virtio_delete_queue(s->ivq); 856 virtio_delete_queue(s->dvq); 857 virtio_delete_queue(s->svq); 858 if (s->free_page_vq) { 859 virtio_delete_queue(s->free_page_vq); 860 } 861 virtio_cleanup(vdev); 862 } 863 864 static void virtio_balloon_device_reset(VirtIODevice *vdev) 865 { 866 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 867 868 if (virtio_balloon_free_page_support(s)) { 869 virtio_balloon_free_page_stop(s); 870 } 871 872 if (s->stats_vq_elem != NULL) { 873 virtqueue_unpop(s->svq, s->stats_vq_elem, 0); 874 g_free(s->stats_vq_elem); 875 s->stats_vq_elem = NULL; 876 } 877 878 s->poison_val = 0; 879 } 880 881 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status) 882 { 883 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 884 885 if (!s->stats_vq_elem && vdev->vm_running && 886 (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) { 887 /* poll stats queue for the element we have discarded when the VM 888 * was stopped */ 889 virtio_balloon_receive_stats(vdev, s->svq); 890 } 891 892 if (virtio_balloon_free_page_support(s)) { 893 /* 894 * The VM is woken up and the iothread was blocked, so signal it to 895 * continue. 896 */ 897 if (vdev->vm_running && s->block_iothread) { 898 qemu_mutex_lock(&s->free_page_lock); 899 s->block_iothread = false; 900 qemu_cond_signal(&s->free_page_cond); 901 qemu_mutex_unlock(&s->free_page_lock); 902 } 903 904 /* The VM is stopped, block the iothread. */ 905 if (!vdev->vm_running) { 906 qemu_mutex_lock(&s->free_page_lock); 907 s->block_iothread = true; 908 qemu_mutex_unlock(&s->free_page_lock); 909 } 910 } 911 } 912 913 static void virtio_balloon_instance_init(Object *obj) 914 { 915 VirtIOBalloon *s = VIRTIO_BALLOON(obj); 916 917 qemu_mutex_init(&s->free_page_lock); 918 qemu_cond_init(&s->free_page_cond); 919 s->free_page_report_cmd_id = VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN; 920 s->free_page_report_notify.notify = virtio_balloon_free_page_report_notify; 921 922 object_property_add(obj, "guest-stats", "guest statistics", 923 balloon_stats_get_all, NULL, NULL, s); 924 925 object_property_add(obj, "guest-stats-polling-interval", "int", 926 balloon_stats_get_poll_interval, 927 balloon_stats_set_poll_interval, 928 NULL, s); 929 } 930 931 static const VMStateDescription vmstate_virtio_balloon = { 932 .name = "virtio-balloon", 933 .minimum_version_id = 1, 934 .version_id = 1, 935 .fields = (VMStateField[]) { 936 VMSTATE_VIRTIO_DEVICE, 937 VMSTATE_END_OF_LIST() 938 }, 939 }; 940 941 static Property virtio_balloon_properties[] = { 942 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features, 943 VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), 944 DEFINE_PROP_BIT("free-page-hint", VirtIOBalloon, host_features, 945 VIRTIO_BALLOON_F_FREE_PAGE_HINT, false), 946 DEFINE_PROP_BIT("page-poison", VirtIOBalloon, host_features, 947 VIRTIO_BALLOON_F_PAGE_POISON, true), 948 /* QEMU 4.0 accidentally changed the config size even when free-page-hint 949 * is disabled, resulting in QEMU 3.1 migration incompatibility. This 950 * property retains this quirk for QEMU 4.1 machine types. 951 */ 952 DEFINE_PROP_BOOL("qemu-4-0-config-size", VirtIOBalloon, 953 qemu_4_0_config_size, false), 954 DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD, 955 IOThread *), 956 DEFINE_PROP_END_OF_LIST(), 957 }; 958 959 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 960 { 961 DeviceClass *dc = DEVICE_CLASS(klass); 962 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 963 964 device_class_set_props(dc, virtio_balloon_properties); 965 dc->vmsd = &vmstate_virtio_balloon; 966 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 967 vdc->realize = virtio_balloon_device_realize; 968 vdc->unrealize = virtio_balloon_device_unrealize; 969 vdc->reset = virtio_balloon_device_reset; 970 vdc->get_config = virtio_balloon_get_config; 971 vdc->set_config = virtio_balloon_set_config; 972 vdc->get_features = virtio_balloon_get_features; 973 vdc->set_status = virtio_balloon_set_status; 974 vdc->vmsd = &vmstate_virtio_balloon_device; 975 } 976 977 static const TypeInfo virtio_balloon_info = { 978 .name = TYPE_VIRTIO_BALLOON, 979 .parent = TYPE_VIRTIO_DEVICE, 980 .instance_size = sizeof(VirtIOBalloon), 981 .instance_init = virtio_balloon_instance_init, 982 .class_init = virtio_balloon_class_init, 983 }; 984 985 static void virtio_register_types(void) 986 { 987 type_register_static(&virtio_balloon_info); 988 } 989 990 type_init(virtio_register_types) 991