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/qapi-events-misc.h"
  28 #include "qapi/visitor.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_HTLB_PGALLOC] = "stat-htlb-pgalloc",
  56    [VIRTIO_BALLOON_S_HTLB_PGFAIL] = "stat-htlb-pgfail",
  57    [VIRTIO_BALLOON_S_NR] = NULL
  58 };
  59
  60 /*
  61  * reset_stats - Mark all items in the stats array as unset
  62  *
  63  * This function needs to be called at device initialization and before
  64  * updating to a set of newly-generated stats.  This will ensure that no
  65  * stale values stick around in case the guest reports a subset of the supported
  66  * statistics.
  67  */
  68 static inline void reset_stats(VirtIOBalloon *dev)
  69 {
  70     int i;
  71     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
  72 }
  73
  74 static bool balloon_stats_supported(const VirtIOBalloon *s)
  75 {
  76     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  77     return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ);
  78 }
  79
  80 static bool balloon_stats_enabled(const VirtIOBalloon *s)
  81 {
  82     return s->stats_poll_interval > 0;
  83 }
  84
  85 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
  86 {
  87     if (balloon_stats_enabled(s)) {
  88         timer_del(s->stats_timer);
  89         timer_free(s->stats_timer);
  90         s->stats_timer = NULL;
  91         s->stats_poll_interval = 0;
  92     }
  93 }
  94
  95 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs)
  96 {
  97     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
  98 }
  99
 100 static void balloon_stats_poll_cb(void *opaque)
 101 {
 102     VirtIOBalloon *s = opaque;
 103     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 104
 105     if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) {
 106         /* re-schedule */
 107         balloon_stats_change_timer(s, s->stats_poll_interval);
 108         return;
 109     }
 110
 111     virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset);
 112     virtio_notify(vdev, s->svq);
 113     g_free(s->stats_vq_elem);
 114     s->stats_vq_elem = NULL;
 115 }
 116
 117 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name,
 118                                   void *opaque, Error **errp)
 119 {
 120     Error *err = NULL;
 121     VirtIOBalloon *s = opaque;
 122     int i;
 123
 124     visit_start_struct(v, name, NULL, 0, &err);
 125     if (err) {
 126         goto out;
 127     }
 128     visit_type_int(v, "last-update", &s->stats_last_update, &err);
 129     if (err) {
 130         goto out_end;
 131     }
 132
 133     visit_start_struct(v, "stats", NULL, 0, &err);
 134     if (err) {
 135         goto out_end;
 136     }
 137     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
 138         visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err);
 139         if (err) {
 140             goto out_nested;
 141         }
 142     }
 143     visit_check_struct(v, &err);
 144 out_nested:
 145     visit_end_struct(v, NULL);
 146
 147     if (!err) {
 148         visit_check_struct(v, &err);
 149     }
 150 out_end:
 151     visit_end_struct(v, NULL);
 152 out:
 153     error_propagate(errp, err);
 154 }
 155
 156 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v,
 157                                             const char *name, void *opaque,
 158                                             Error **errp)
 159 {
 160     VirtIOBalloon *s = opaque;
 161     visit_type_int(v, name, &s->stats_poll_interval, errp);
 162 }
 163
 164 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
 165                                             const char *name, void *opaque,
 166                                             Error **errp)
 167 {
 168     VirtIOBalloon *s = opaque;
 169     Error *local_err = NULL;
 170     int64_t value;
 171
 172     visit_type_int(v, name, &value, &local_err);
 173     if (local_err) {
 174         error_propagate(errp, local_err);
 175         return;
 176     }
 177
 178     if (value < 0) {
 179         error_setg(errp, "timer value must be greater than zero");
 180         return;
 181     }
 182
 183     if (value > UINT32_MAX) {
 184         error_setg(errp, "timer value is too big");
 185         return;
 186     }
 187
 188     if (value == s->stats_poll_interval) {
 189         return;
 190     }
 191
 192     if (value == 0) {
 193         /* timer=0 disables the timer */
 194         balloon_stats_destroy_timer(s);
 195         return;
 196     }
 197
 198     if (balloon_stats_enabled(s)) {
 199         /* timer interval change */
 200         s->stats_poll_interval = value;
 201         balloon_stats_change_timer(s, value);
 202         return;
 203     }
 204
 205     /* create a new timer */
 206     g_assert(s->stats_timer == NULL);
 207     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 208     s->stats_poll_interval = value;
 209     balloon_stats_change_timer(s, 0);
 210 }
 211
 212 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 213 {
 214     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 215     VirtQueueElement *elem;
 216     MemoryRegionSection section;
 217
 218     for (;;) {
 219         size_t offset = 0;
 220         uint32_t pfn;
 221         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 222         if (!elem) {
 223             return;
 224         }
 225
 226         while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) {
 227             ram_addr_t pa;
 228             ram_addr_t addr;
 229             int p = virtio_ldl_p(vdev, &pfn);
 230
 231             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 232             offset += 4;
 233
 234             /* FIXME: remove get_system_memory(), but how? */
 235             section = memory_region_find(get_system_memory(), pa, 1);
 236             if (!int128_nz(section.size) ||
 237                 !memory_region_is_ram(section.mr) ||
 238                 memory_region_is_rom(section.mr) ||
 239                 memory_region_is_romd(section.mr)) {
 240                 trace_virtio_balloon_bad_addr(pa);
 241                 memory_region_unref(section.mr);
 242                 continue;
 243             }
 244
 245             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 246                                                pa);
 247             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 248                should be OK because we only want a single page.  */
 249             addr = section.offset_within_region;
 250             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 251                          !!(vq == s->dvq));
 252             memory_region_unref(section.mr);
 253         }
 254
 255         virtqueue_push(vq, elem, offset);
 256         virtio_notify(vdev, vq);
 257         g_free(elem);
 258     }
 259 }
 260
 261 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 262 {
 263     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 264     VirtQueueElement *elem;
 265     VirtIOBalloonStat stat;
 266     size_t offset = 0;
 267     qemu_timeval tv;
 268
 269     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 270     if (!elem) {
 271         goto out;
 272     }
 273
 274     if (s->stats_vq_elem != NULL) {
 275         /* This should never happen if the driver follows the spec. */
 276         virtqueue_push(vq, s->stats_vq_elem, 0);
 277         virtio_notify(vdev, vq);
 278         g_free(s->stats_vq_elem);
 279     }
 280
 281     s->stats_vq_elem = elem;
 282
 283     /* Initialize the stats to get rid of any stale values.  This is only
 284      * needed to handle the case where a guest supports fewer stats than it
 285      * used to (ie. it has booted into an old kernel).
 286      */
 287     reset_stats(s);
 288
 289     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 290            == sizeof(stat)) {
 291         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 292         uint64_t val = virtio_tswap64(vdev, stat.val);
 293
 294         offset += sizeof(stat);
 295         if (tag < VIRTIO_BALLOON_S_NR)
 296             s->stats[tag] = val;
 297     }
 298     s->stats_vq_offset = offset;
 299
 300     if (qemu_gettimeofday(&tv) < 0) {
 301         warn_report("%s: failed to get time of day", __func__);
 302         goto out;
 303     }
 304
 305     s->stats_last_update = tv.tv_sec;
 306
 307 out:
 308     if (balloon_stats_enabled(s)) {
 309         balloon_stats_change_timer(s, s->stats_poll_interval);
 310     }
 311 }
 312
 313 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 314 {
 315     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 316     struct virtio_balloon_config config;
 317
 318     config.num_pages = cpu_to_le32(dev->num_pages);
 319     config.actual = cpu_to_le32(dev->actual);
 320
 321     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 322     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 323 }
 324
 325 static int build_dimm_list(Object *obj, void *opaque)
 326 {
 327     GSList **list = opaque;
 328
 329     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
 330         DeviceState *dev = DEVICE(obj);
 331         if (dev->realized) { /* only realized DIMMs matter */
 332             *list = g_slist_prepend(*list, dev);
 333         }
 334     }
 335
 336     object_child_foreach(obj, build_dimm_list, opaque);
 337     return 0;
 338 }
 339
 340 static ram_addr_t get_current_ram_size(void)
 341 {
 342     GSList *list = NULL, *item;
 343     ram_addr_t size = ram_size;
 344
 345     build_dimm_list(qdev_get_machine(), &list);
 346     for (item = list; item; item = g_slist_next(item)) {
 347         Object *obj = OBJECT(item->data);
 348         if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) {
 349             size += object_property_get_int(obj, PC_DIMM_SIZE_PROP,
 350                                             &error_abort);
 351         }
 352     }
 353     g_slist_free(list);
 354
 355     return size;
 356 }
 357
 358 static void virtio_balloon_set_config(VirtIODevice *vdev,
 359                                       const uint8_t *config_data)
 360 {
 361     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 362     struct virtio_balloon_config config;
 363     uint32_t oldactual = dev->actual;
 364     ram_addr_t vm_ram_size = get_current_ram_size();
 365
 366     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 367     dev->actual = le32_to_cpu(config.actual);
 368     if (dev->actual != oldactual) {
 369         qapi_event_send_balloon_change(vm_ram_size -
 370                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 371                         &error_abort);
 372     }
 373     trace_virtio_balloon_set_config(dev->actual, oldactual);
 374 }
 375
 376 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 377                                             Error **errp)
 378 {
 379     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 380     f |= dev->host_features;
 381     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 382     return f;
 383 }
 384
 385 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 386 {
 387     VirtIOBalloon *dev = opaque;
 388     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 389                                              VIRTIO_BALLOON_PFN_SHIFT);
 390 }
 391
 392 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 393 {
 394     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 395     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 396     ram_addr_t vm_ram_size = get_current_ram_size();
 397
 398     if (target > vm_ram_size) {
 399         target = vm_ram_size;
 400     }
 401     if (target) {
 402         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 403         virtio_notify_config(vdev);
 404     }
 405     trace_virtio_balloon_to_target(target, dev->num_pages);
 406 }
 407
 408 static int virtio_balloon_post_load_device(void *opaque, int version_id)
 409 {
 410     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 411
 412     if (balloon_stats_enabled(s)) {
 413         balloon_stats_change_timer(s, s->stats_poll_interval);
 414     }
 415     return 0;
 416 }
 417
 418 static const VMStateDescription vmstate_virtio_balloon_device = {
 419     .name = "virtio-balloon-device",
 420     .version_id = 1,
 421     .minimum_version_id = 1,
 422     .post_load = virtio_balloon_post_load_device,
 423     .fields = (VMStateField[]) {
 424         VMSTATE_UINT32(num_pages, VirtIOBalloon),
 425         VMSTATE_UINT32(actual, VirtIOBalloon),
 426         VMSTATE_END_OF_LIST()
 427     },
 428 };
 429
 430 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 431 {
 432     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 433     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 434     int ret;
 435
 436     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 437                 sizeof(struct virtio_balloon_config));
 438
 439     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 440                                    virtio_balloon_stat, s);
 441
 442     if (ret < 0) {
 443         error_setg(errp, "Only one balloon device is supported");
 444         virtio_cleanup(vdev);
 445         return;
 446     }
 447
 448     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 449     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 450     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 451
 452     reset_stats(s);
 453 }
 454
 455 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 456 {
 457     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 458     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 459
 460     balloon_stats_destroy_timer(s);
 461     qemu_remove_balloon_handler(s);
 462     virtio_cleanup(vdev);
 463 }
 464
 465 static void virtio_balloon_device_reset(VirtIODevice *vdev)
 466 {
 467     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 468
 469     if (s->stats_vq_elem != NULL) {
 470         virtqueue_unpop(s->svq, s->stats_vq_elem, 0);
 471         g_free(s->stats_vq_elem);
 472         s->stats_vq_elem = NULL;
 473     }
 474 }
 475
 476 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status)
 477 {
 478     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 479
 480     if (!s->stats_vq_elem && vdev->vm_running &&
 481         (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) {
 482         /* poll stats queue for the element we have discarded when the VM
 483          * was stopped */
 484         virtio_balloon_receive_stats(vdev, s->svq);
 485     }
 486 }
 487
 488 static void virtio_balloon_instance_init(Object *obj)
 489 {
 490     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 491
 492     object_property_add(obj, "guest-stats", "guest statistics",
 493                         balloon_stats_get_all, NULL, NULL, s, NULL);
 494
 495     object_property_add(obj, "guest-stats-polling-interval", "int",
 496                         balloon_stats_get_poll_interval,
 497                         balloon_stats_set_poll_interval,
 498                         NULL, s, NULL);
 499 }
 500
 501 static const VMStateDescription vmstate_virtio_balloon = {
 502     .name = "virtio-balloon",
 503     .minimum_version_id = 1,
 504     .version_id = 1,
 505     .fields = (VMStateField[]) {
 506         VMSTATE_VIRTIO_DEVICE,
 507         VMSTATE_END_OF_LIST()
 508     },
 509 };
 510
 511 static Property virtio_balloon_properties[] = {
 512     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 513                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 514     DEFINE_PROP_END_OF_LIST(),
 515 };
 516
 517 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 518 {
 519     DeviceClass *dc = DEVICE_CLASS(klass);
 520     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 521
 522     dc->props = virtio_balloon_properties;
 523     dc->vmsd = &vmstate_virtio_balloon;
 524     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 525     vdc->realize = virtio_balloon_device_realize;
 526     vdc->unrealize = virtio_balloon_device_unrealize;
 527     vdc->reset = virtio_balloon_device_reset;
 528     vdc->get_config = virtio_balloon_get_config;
 529     vdc->set_config = virtio_balloon_set_config;
 530     vdc->get_features = virtio_balloon_get_features;
 531     vdc->set_status = virtio_balloon_set_status;
 532     vdc->vmsd = &vmstate_virtio_balloon_device;
 533 }
 534
 535 static const TypeInfo virtio_balloon_info = {
 536     .name = TYPE_VIRTIO_BALLOON,
 537     .parent = TYPE_VIRTIO_DEVICE,
 538     .instance_size = sizeof(VirtIOBalloon),
 539     .instance_init = virtio_balloon_instance_init,
 540     .class_init = virtio_balloon_class_init,
 541 };
 542
 543 static void virtio_register_types(void)
 544 {
 545     type_register_static(&virtio_balloon_info);
 546 }
 547
 548 type_init(virtio_register_types)