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