hw/virtio/virtio-balloon.c

   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 "sysemu/kvm.h"
  25 #include "exec/address-spaces.h"
  26 #include "qapi/error.h"
  27 #include "qapi/visitor.h"
  28 #include "qapi-event.h"
  29 #include "trace.h"
  30 #include "qemu/error-report.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 static void balloon_page(void *addr, int deflate)
  38 {
  39     if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
  40                                          kvm_has_sync_mmu())) {
  41         qemu_madvise(addr, BALLOON_PAGE_SIZE,
  42                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
  43     }
  44 }
  45
  46 static const char *balloon_stat_names[] = {
  47    [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
  48    [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
  49    [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
  50    [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
  51    [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
  52    [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
  53    [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory",
  54    [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches",
  55    [VIRTIO_BALLOON_S_NR] = NULL
  56 };
  57
  58 /*
  59  * reset_stats - Mark all items in the stats array as unset
  60  *
  61  * This function needs to be called at device initialization and before
  62  * updating to a set of newly-generated stats.  This will ensure that no
  63  * stale values stick around in case the guest reports a subset of the supported
  64  * statistics.
  65  */
  66 static inline void reset_stats(VirtIOBalloon *dev)
  67 {
  68     int i;
  69     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
  70 }
  71
  72 static bool balloon_stats_supported(const VirtIOBalloon *s)
  73 {
  74     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  75     return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ);
  76 }
  77
  78 static bool balloon_stats_enabled(const VirtIOBalloon *s)
  79 {
  80     return s->stats_poll_interval > 0;
  81 }
  82
  83 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
  84 {
  85     if (balloon_stats_enabled(s)) {
  86         timer_del(s->stats_timer);
  87         timer_free(s->stats_timer);
  88         s->stats_timer = NULL;
  89         s->stats_poll_interval = 0;
  90     }
  91 }
  92
  93 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs)
  94 {
  95     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
  96 }
  97
  98 static void balloon_stats_poll_cb(void *opaque)
  99 {
 100     VirtIOBalloon *s = opaque;
 101     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 102
 103     if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) {
 104         /* re-schedule */
 105         balloon_stats_change_timer(s, s->stats_poll_interval);
 106         return;
 107     }
 108
 109     virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset);
 110     virtio_notify(vdev, s->svq);
 111     g_free(s->stats_vq_elem);
 112     s->stats_vq_elem = NULL;
 113 }
 114
 115 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name,
 116                                   void *opaque, Error **errp)
 117 {
 118     Error *err = NULL;
 119     VirtIOBalloon *s = opaque;
 120     int i;
 121
 122     visit_start_struct(v, name, NULL, 0, &err);
 123     if (err) {
 124         goto out;
 125     }
 126     visit_type_int(v, "last-update", &s->stats_last_update, &err);
 127     if (err) {
 128         goto out_end;
 129     }
 130
 131     visit_start_struct(v, "stats", NULL, 0, &err);
 132     if (err) {
 133         goto out_end;
 134     }
 135     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
 136         visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err);
 137         if (err) {
 138             goto out_nested;
 139         }
 140     }
 141     visit_check_struct(v, &err);
 142 out_nested:
 143     visit_end_struct(v, NULL);
 144
 145     if (!err) {
 146         visit_check_struct(v, &err);
 147     }
 148 out_end:
 149     visit_end_struct(v, NULL);
 150 out:
 151     error_propagate(errp, err);
 152 }
 153
 154 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v,
 155                                             const char *name, void *opaque,
 156                                             Error **errp)
 157 {
 158     VirtIOBalloon *s = opaque;
 159     visit_type_int(v, name, &s->stats_poll_interval, errp);
 160 }
 161
 162 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
 163                                             const char *name, void *opaque,
 164                                             Error **errp)
 165 {
 166     VirtIOBalloon *s = opaque;
 167     Error *local_err = NULL;
 168     int64_t value;
 169
 170     visit_type_int(v, name, &value, &local_err);
 171     if (local_err) {
 172         error_propagate(errp, local_err);
 173         return;
 174     }
 175
 176     if (value < 0) {
 177         error_setg(errp, "timer value must be greater than zero");
 178         return;
 179     }
 180
 181     if (value > UINT32_MAX) {
 182         error_setg(errp, "timer value is too big");
 183         return;
 184     }
 185
 186     if (value == s->stats_poll_interval) {
 187         return;
 188     }
 189
 190     if (value == 0) {
 191         /* timer=0 disables the timer */
 192         balloon_stats_destroy_timer(s);
 193         return;
 194     }
 195
 196     if (balloon_stats_enabled(s)) {
 197         /* timer interval change */
 198         s->stats_poll_interval = value;
 199         balloon_stats_change_timer(s, value);
 200         return;
 201     }
 202
 203     /* create a new timer */
 204     g_assert(s->stats_timer == NULL);
 205     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 206     s->stats_poll_interval = value;
 207     balloon_stats_change_timer(s, 0);
 208 }
 209
 210 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 211 {
 212     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 213     VirtQueueElement *elem;
 214     MemoryRegionSection section;
 215
 216     for (;;) {
 217         size_t offset = 0;
 218         uint32_t pfn;
 219         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 220         if (!elem) {
 221             return;
 222         }
 223
 224         while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) {
 225             ram_addr_t pa;
 226             ram_addr_t addr;
 227             int p = virtio_ldl_p(vdev, &pfn);
 228
 229             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 230             offset += 4;
 231
 232             /* FIXME: remove get_system_memory(), but how? */
 233             section = memory_region_find(get_system_memory(), pa, 1);
 234             if (!int128_nz(section.size) ||
 235                 !memory_region_is_ram(section.mr) ||
 236                 memory_region_is_rom(section.mr) ||
 237                 memory_region_is_romd(section.mr)) {
 238                 trace_virtio_balloon_bad_addr(pa);
 239                 memory_region_unref(section.mr);
 240                 continue;
 241             }
 242
 243             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 244                                                pa);
 245             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 246                should be OK because we only want a single page.  */
 247             addr = section.offset_within_region;
 248             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 249                          !!(vq == s->dvq));
 250             memory_region_unref(section.mr);
 251         }
 252
 253         virtqueue_push(vq, elem, offset);
 254         virtio_notify(vdev, vq);
 255         g_free(elem);
 256     }
 257 }
 258
 259 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 260 {
 261     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 262     VirtQueueElement *elem;
 263     VirtIOBalloonStat stat;
 264     size_t offset = 0;
 265     qemu_timeval tv;
 266
 267     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 268     if (!elem) {
 269         goto out;
 270     }
 271
 272     if (s->stats_vq_elem != NULL) {
 273         /* This should never happen if the driver follows the spec. */
 274         virtqueue_push(vq, s->stats_vq_elem, 0);
 275         virtio_notify(vdev, vq);
 276         g_free(s->stats_vq_elem);
 277     }
 278
 279     s->stats_vq_elem = elem;
 280
 281     /* Initialize the stats to get rid of any stale values.  This is only
 282      * needed to handle the case where a guest supports fewer stats than it
 283      * used to (ie. it has booted into an old kernel).
 284      */
 285     reset_stats(s);
 286
 287     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 288            == sizeof(stat)) {
 289         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 290         uint64_t val = virtio_tswap64(vdev, stat.val);
 291
 292         offset += sizeof(stat);
 293         if (tag < VIRTIO_BALLOON_S_NR)
 294             s->stats[tag] = val;
 295     }
 296     s->stats_vq_offset = offset;
 297
 298     if (qemu_gettimeofday(&tv) < 0) {
 299         warn_report("%s: failed to get time of day", __func__);
 300         goto out;
 301     }
 302
 303     s->stats_last_update = tv.tv_sec;
 304
 305 out:
 306     if (balloon_stats_enabled(s)) {
 307         balloon_stats_change_timer(s, s->stats_poll_interval);
 308     }
 309 }
 310
 311 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 312 {
 313     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 314     struct virtio_balloon_config config;
 315
 316     config.num_pages = cpu_to_le32(dev->num_pages);
 317     config.actual = cpu_to_le32(dev->actual);
 318
 319     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 320     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 321 }
 322
 323 static int build_dimm_list(Object *obj, void *opaque)
 324 {
 325     GSList **list = opaque;
 326
 327     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
 328         DeviceState *dev = DEVICE(obj);
 329         if (dev->realized) { /* only realized DIMMs matter */
 330             *list = g_slist_prepend(*list, dev);
 331         }
 332     }
 333
 334     object_child_foreach(obj, build_dimm_list, opaque);
 335     return 0;
 336 }
 337
 338 static ram_addr_t get_current_ram_size(void)
 339 {
 340     GSList *list = NULL, *item;
 341     ram_addr_t size = ram_size;
 342
 343     build_dimm_list(qdev_get_machine(), &list);
 344     for (item = list; item; item = g_slist_next(item)) {
 345         Object *obj = OBJECT(item->data);
 346         if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) {
 347             size += object_property_get_int(obj, PC_DIMM_SIZE_PROP,
 348                                             &error_abort);
 349         }
 350     }
 351     g_slist_free(list);
 352
 353     return size;
 354 }
 355
 356 static void virtio_balloon_set_config(VirtIODevice *vdev,
 357                                       const uint8_t *config_data)
 358 {
 359     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 360     struct virtio_balloon_config config;
 361     uint32_t oldactual = dev->actual;
 362     ram_addr_t vm_ram_size = get_current_ram_size();
 363
 364     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 365     dev->actual = le32_to_cpu(config.actual);
 366     if (dev->actual != oldactual) {
 367         qapi_event_send_balloon_change(vm_ram_size -
 368                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 369                         &error_abort);
 370     }
 371     trace_virtio_balloon_set_config(dev->actual, oldactual);
 372 }
 373
 374 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 375                                             Error **errp)
 376 {
 377     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 378     f |= dev->host_features;
 379     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 380     return f;
 381 }
 382
 383 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 384 {
 385     VirtIOBalloon *dev = opaque;
 386     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 387                                              VIRTIO_BALLOON_PFN_SHIFT);
 388 }
 389
 390 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 391 {
 392     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 393     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 394     ram_addr_t vm_ram_size = get_current_ram_size();
 395
 396     if (target > vm_ram_size) {
 397         target = vm_ram_size;
 398     }
 399     if (target) {
 400         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 401         virtio_notify_config(vdev);
 402     }
 403     trace_virtio_balloon_to_target(target, dev->num_pages);
 404 }
 405
 406 static int virtio_balloon_post_load_device(void *opaque, int version_id)
 407 {
 408     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 409
 410     if (balloon_stats_enabled(s)) {
 411         balloon_stats_change_timer(s, s->stats_poll_interval);
 412     }
 413     return 0;
 414 }
 415
 416 static const VMStateDescription vmstate_virtio_balloon_device = {
 417     .name = "virtio-balloon-device",
 418     .version_id = 1,
 419     .minimum_version_id = 1,
 420     .post_load = virtio_balloon_post_load_device,
 421     .fields = (VMStateField[]) {
 422         VMSTATE_UINT32(num_pages, VirtIOBalloon),
 423         VMSTATE_UINT32(actual, VirtIOBalloon),
 424         VMSTATE_END_OF_LIST()
 425     },
 426 };
 427
 428 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 429 {
 430     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 431     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 432     int ret;
 433
 434     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 435                 sizeof(struct virtio_balloon_config));
 436
 437     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 438                                    virtio_balloon_stat, s);
 439
 440     if (ret < 0) {
 441         error_setg(errp, "Only one balloon device is supported");
 442         virtio_cleanup(vdev);
 443         return;
 444     }
 445
 446     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 447     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 448     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 449
 450     reset_stats(s);
 451 }
 452
 453 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 454 {
 455     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 456     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 457
 458     balloon_stats_destroy_timer(s);
 459     qemu_remove_balloon_handler(s);
 460     virtio_cleanup(vdev);
 461 }
 462
 463 static void virtio_balloon_device_reset(VirtIODevice *vdev)
 464 {
 465     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 466
 467     if (s->stats_vq_elem != NULL) {
 468         virtqueue_unpop(s->svq, s->stats_vq_elem, 0);
 469         g_free(s->stats_vq_elem);
 470         s->stats_vq_elem = NULL;
 471     }
 472 }
 473
 474 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status)
 475 {
 476     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 477
 478     if (!s->stats_vq_elem && vdev->vm_running &&
 479         (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) {
 480         /* poll stats queue for the element we have discarded when the VM
 481          * was stopped */
 482         virtio_balloon_receive_stats(vdev, s->svq);
 483     }
 484 }
 485
 486 static void virtio_balloon_instance_init(Object *obj)
 487 {
 488     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 489
 490     object_property_add(obj, "guest-stats", "guest statistics",
 491                         balloon_stats_get_all, NULL, NULL, s, NULL);
 492
 493     object_property_add(obj, "guest-stats-polling-interval", "int",
 494                         balloon_stats_get_poll_interval,
 495                         balloon_stats_set_poll_interval,
 496                         NULL, s, NULL);
 497 }
 498
 499 static const VMStateDescription vmstate_virtio_balloon = {
 500     .name = "virtio-balloon",
 501     .minimum_version_id = 1,
 502     .version_id = 1,
 503     .fields = (VMStateField[]) {
 504         VMSTATE_VIRTIO_DEVICE,
 505         VMSTATE_END_OF_LIST()
 506     },
 507 };
 508
 509 static Property virtio_balloon_properties[] = {
 510     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 511                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 512     DEFINE_PROP_END_OF_LIST(),
 513 };
 514
 515 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 516 {
 517     DeviceClass *dc = DEVICE_CLASS(klass);
 518     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 519
 520     dc->props = virtio_balloon_properties;
 521     dc->vmsd = &vmstate_virtio_balloon;
 522     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 523     vdc->realize = virtio_balloon_device_realize;
 524     vdc->unrealize = virtio_balloon_device_unrealize;
 525     vdc->reset = virtio_balloon_device_reset;
 526     vdc->get_config = virtio_balloon_get_config;
 527     vdc->set_config = virtio_balloon_set_config;
 528     vdc->get_features = virtio_balloon_get_features;
 529     vdc->set_status = virtio_balloon_set_status;
 530     vdc->vmsd = &vmstate_virtio_balloon_device;
 531 }
 532
 533 static const TypeInfo virtio_balloon_info = {
 534     .name = TYPE_VIRTIO_BALLOON,
 535     .parent = TYPE_VIRTIO_DEVICE,
 536     .instance_size = sizeof(VirtIOBalloon),
 537     .instance_init = virtio_balloon_instance_init,
 538     .class_init = virtio_balloon_class_init,
 539 };
 540
 541 static void virtio_register_types(void)
 542 {
 543     type_register_static(&virtio_balloon_info);
 544 }
 545
 546 type_init(virtio_register_types)