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/i386/pc.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/visitor.h"
  27 #include "qapi-event.h"
  28 #include "trace.h"
  29 #include "qemu/error-report.h"
  30
  31 #include "hw/virtio/virtio-bus.h"
  32 #include "hw/virtio/virtio-access.h"
  33
  34 #define BALLOON_PAGE_SIZE  (1 << VIRTIO_BALLOON_PFN_SHIFT)
  35
  36 static void balloon_page(void *addr, int deflate)
  37 {
  38     if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
  39                                          kvm_has_sync_mmu())) {
  40         qemu_madvise(addr, BALLOON_PAGE_SIZE,
  41                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
  42     }
  43 }
  44
  45 static const char *balloon_stat_names[] = {
  46    [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
  47    [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
  48    [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
  49    [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
  50    [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
  51    [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
  52    [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory",
  53    [VIRTIO_BALLOON_S_NR] = NULL
  54 };
  55
  56 /*
  57  * reset_stats - Mark all items in the stats array as unset
  58  *
  59  * This function needs to be called at device initialization and before
  60  * updating to a set of newly-generated stats.  This will ensure that no
  61  * stale values stick around in case the guest reports a subset of the supported
  62  * statistics.
  63  */
  64 static inline void reset_stats(VirtIOBalloon *dev)
  65 {
  66     int i;
  67     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
  68 }
  69
  70 static bool balloon_stats_supported(const VirtIOBalloon *s)
  71 {
  72     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  73     return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ);
  74 }
  75
  76 static bool balloon_stats_enabled(const VirtIOBalloon *s)
  77 {
  78     return s->stats_poll_interval > 0;
  79 }
  80
  81 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
  82 {
  83     if (balloon_stats_enabled(s)) {
  84         timer_del(s->stats_timer);
  85         timer_free(s->stats_timer);
  86         s->stats_timer = NULL;
  87         s->stats_poll_interval = 0;
  88     }
  89 }
  90
  91 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs)
  92 {
  93     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
  94 }
  95
  96 static void balloon_stats_poll_cb(void *opaque)
  97 {
  98     VirtIOBalloon *s = opaque;
  99     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 100
 101     if (s->stats_vq_elem == NULL || !balloon_stats_supported(s)) {
 102         /* re-schedule */
 103         balloon_stats_change_timer(s, s->stats_poll_interval);
 104         return;
 105     }
 106
 107     virtqueue_push(s->svq, s->stats_vq_elem, s->stats_vq_offset);
 108     virtio_notify(vdev, s->svq);
 109     g_free(s->stats_vq_elem);
 110     s->stats_vq_elem = NULL;
 111 }
 112
 113 static void balloon_stats_get_all(Object *obj, Visitor *v, const char *name,
 114                                   void *opaque, Error **errp)
 115 {
 116     Error *err = NULL;
 117     VirtIOBalloon *s = opaque;
 118     int i;
 119
 120     visit_start_struct(v, name, NULL, 0, &err);
 121     if (err) {
 122         goto out;
 123     }
 124     visit_type_int(v, "last-update", &s->stats_last_update, &err);
 125     if (err) {
 126         goto out_end;
 127     }
 128
 129     visit_start_struct(v, "stats", NULL, 0, &err);
 130     if (err) {
 131         goto out_end;
 132     }
 133     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
 134         visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err);
 135         if (err) {
 136             goto out_nested;
 137         }
 138     }
 139     visit_check_struct(v, &err);
 140 out_nested:
 141     visit_end_struct(v, NULL);
 142
 143     if (!err) {
 144         visit_check_struct(v, &err);
 145     }
 146 out_end:
 147     visit_end_struct(v, NULL);
 148 out:
 149     error_propagate(errp, err);
 150 }
 151
 152 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v,
 153                                             const char *name, void *opaque,
 154                                             Error **errp)
 155 {
 156     VirtIOBalloon *s = opaque;
 157     visit_type_int(v, name, &s->stats_poll_interval, errp);
 158 }
 159
 160 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
 161                                             const char *name, void *opaque,
 162                                             Error **errp)
 163 {
 164     VirtIOBalloon *s = opaque;
 165     Error *local_err = NULL;
 166     int64_t value;
 167
 168     visit_type_int(v, name, &value, &local_err);
 169     if (local_err) {
 170         error_propagate(errp, local_err);
 171         return;
 172     }
 173
 174     if (value < 0) {
 175         error_setg(errp, "timer value must be greater than zero");
 176         return;
 177     }
 178
 179     if (value > UINT32_MAX) {
 180         error_setg(errp, "timer value is too big");
 181         return;
 182     }
 183
 184     if (value == s->stats_poll_interval) {
 185         return;
 186     }
 187
 188     if (value == 0) {
 189         /* timer=0 disables the timer */
 190         balloon_stats_destroy_timer(s);
 191         return;
 192     }
 193
 194     if (balloon_stats_enabled(s)) {
 195         /* timer interval change */
 196         s->stats_poll_interval = value;
 197         balloon_stats_change_timer(s, value);
 198         return;
 199     }
 200
 201     /* create a new timer */
 202     g_assert(s->stats_timer == NULL);
 203     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 204     s->stats_poll_interval = value;
 205     balloon_stats_change_timer(s, 0);
 206 }
 207
 208 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 209 {
 210     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 211     VirtQueueElement *elem;
 212     MemoryRegionSection section;
 213
 214     for (;;) {
 215         size_t offset = 0;
 216         uint32_t pfn;
 217         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 218         if (!elem) {
 219             return;
 220         }
 221
 222         while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) {
 223             ram_addr_t pa;
 224             ram_addr_t addr;
 225             int p = virtio_ldl_p(vdev, &pfn);
 226
 227             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 228             offset += 4;
 229
 230             /* FIXME: remove get_system_memory(), but how? */
 231             section = memory_region_find(get_system_memory(), pa, 1);
 232             if (!int128_nz(section.size) ||
 233                 !memory_region_is_ram(section.mr) ||
 234                 memory_region_is_rom(section.mr) ||
 235                 memory_region_is_romd(section.mr)) {
 236                 trace_virtio_balloon_bad_addr(pa);
 237                 continue;
 238             }
 239
 240             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 241                                                pa);
 242             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 243                should be OK because we only want a single page.  */
 244             addr = section.offset_within_region;
 245             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 246                          !!(vq == s->dvq));
 247             memory_region_unref(section.mr);
 248         }
 249
 250         virtqueue_push(vq, elem, offset);
 251         virtio_notify(vdev, vq);
 252         g_free(elem);
 253     }
 254 }
 255
 256 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 257 {
 258     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 259     VirtQueueElement *elem;
 260     VirtIOBalloonStat stat;
 261     size_t offset = 0;
 262     qemu_timeval tv;
 263
 264     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 265     if (!elem) {
 266         goto out;
 267     }
 268
 269     if (s->stats_vq_elem != NULL) {
 270         /* This should never happen if the driver follows the spec. */
 271         virtqueue_push(vq, s->stats_vq_elem, 0);
 272         virtio_notify(vdev, vq);
 273         g_free(s->stats_vq_elem);
 274     }
 275
 276     s->stats_vq_elem = elem;
 277
 278     /* Initialize the stats to get rid of any stale values.  This is only
 279      * needed to handle the case where a guest supports fewer stats than it
 280      * used to (ie. it has booted into an old kernel).
 281      */
 282     reset_stats(s);
 283
 284     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 285            == sizeof(stat)) {
 286         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 287         uint64_t val = virtio_tswap64(vdev, stat.val);
 288
 289         offset += sizeof(stat);
 290         if (tag < VIRTIO_BALLOON_S_NR)
 291             s->stats[tag] = val;
 292     }
 293     s->stats_vq_offset = offset;
 294
 295     if (qemu_gettimeofday(&tv) < 0) {
 296         warn_report("%s: failed to get time of day", __func__);
 297         goto out;
 298     }
 299
 300     s->stats_last_update = tv.tv_sec;
 301
 302 out:
 303     if (balloon_stats_enabled(s)) {
 304         balloon_stats_change_timer(s, s->stats_poll_interval);
 305     }
 306 }
 307
 308 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 309 {
 310     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 311     struct virtio_balloon_config config;
 312
 313     config.num_pages = cpu_to_le32(dev->num_pages);
 314     config.actual = cpu_to_le32(dev->actual);
 315
 316     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 317     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 318 }
 319
 320 static int build_dimm_list(Object *obj, void *opaque)
 321 {
 322     GSList **list = opaque;
 323
 324     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
 325         DeviceState *dev = DEVICE(obj);
 326         if (dev->realized) { /* only realized DIMMs matter */
 327             *list = g_slist_prepend(*list, dev);
 328         }
 329     }
 330
 331     object_child_foreach(obj, build_dimm_list, opaque);
 332     return 0;
 333 }
 334
 335 static ram_addr_t get_current_ram_size(void)
 336 {
 337     GSList *list = NULL, *item;
 338     ram_addr_t size = ram_size;
 339
 340     build_dimm_list(qdev_get_machine(), &list);
 341     for (item = list; item; item = g_slist_next(item)) {
 342         Object *obj = OBJECT(item->data);
 343         if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) {
 344             size += object_property_get_int(obj, PC_DIMM_SIZE_PROP,
 345                                             &error_abort);
 346         }
 347     }
 348     g_slist_free(list);
 349
 350     return size;
 351 }
 352
 353 static void virtio_balloon_set_config(VirtIODevice *vdev,
 354                                       const uint8_t *config_data)
 355 {
 356     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 357     struct virtio_balloon_config config;
 358     uint32_t oldactual = dev->actual;
 359     ram_addr_t vm_ram_size = get_current_ram_size();
 360
 361     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 362     dev->actual = le32_to_cpu(config.actual);
 363     if (dev->actual != oldactual) {
 364         qapi_event_send_balloon_change(vm_ram_size -
 365                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 366                         &error_abort);
 367     }
 368     trace_virtio_balloon_set_config(dev->actual, oldactual);
 369 }
 370
 371 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 372                                             Error **errp)
 373 {
 374     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 375     f |= dev->host_features;
 376     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 377     return f;
 378 }
 379
 380 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 381 {
 382     VirtIOBalloon *dev = opaque;
 383     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 384                                              VIRTIO_BALLOON_PFN_SHIFT);
 385 }
 386
 387 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 388 {
 389     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 390     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 391     ram_addr_t vm_ram_size = get_current_ram_size();
 392
 393     if (target > vm_ram_size) {
 394         target = vm_ram_size;
 395     }
 396     if (target) {
 397         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 398         virtio_notify_config(vdev);
 399     }
 400     trace_virtio_balloon_to_target(target, dev->num_pages);
 401 }
 402
 403 static int virtio_balloon_post_load_device(void *opaque, int version_id)
 404 {
 405     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 406
 407     if (balloon_stats_enabled(s)) {
 408         balloon_stats_change_timer(s, s->stats_poll_interval);
 409     }
 410     return 0;
 411 }
 412
 413 static const VMStateDescription vmstate_virtio_balloon_device = {
 414     .name = "virtio-balloon-device",
 415     .version_id = 1,
 416     .minimum_version_id = 1,
 417     .post_load = virtio_balloon_post_load_device,
 418     .fields = (VMStateField[]) {
 419         VMSTATE_UINT32(num_pages, VirtIOBalloon),
 420         VMSTATE_UINT32(actual, VirtIOBalloon),
 421         VMSTATE_END_OF_LIST()
 422     },
 423 };
 424
 425 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 426 {
 427     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 428     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 429     int ret;
 430
 431     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 432                 sizeof(struct virtio_balloon_config));
 433
 434     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 435                                    virtio_balloon_stat, s);
 436
 437     if (ret < 0) {
 438         error_setg(errp, "Only one balloon device is supported");
 439         virtio_cleanup(vdev);
 440         return;
 441     }
 442
 443     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 444     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 445     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 446
 447     reset_stats(s);
 448 }
 449
 450 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 451 {
 452     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 453     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 454
 455     balloon_stats_destroy_timer(s);
 456     qemu_remove_balloon_handler(s);
 457     virtio_cleanup(vdev);
 458 }
 459
 460 static void virtio_balloon_device_reset(VirtIODevice *vdev)
 461 {
 462     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 463
 464     if (s->stats_vq_elem != NULL) {
 465         virtqueue_unpop(s->svq, s->stats_vq_elem, 0);
 466         g_free(s->stats_vq_elem);
 467         s->stats_vq_elem = NULL;
 468     }
 469 }
 470
 471 static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status)
 472 {
 473     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 474
 475     if (!s->stats_vq_elem && vdev->vm_running &&
 476         (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) {
 477         /* poll stats queue for the element we have discarded when the VM
 478          * was stopped */
 479         virtio_balloon_receive_stats(vdev, s->svq);
 480     }
 481 }
 482
 483 static void virtio_balloon_instance_init(Object *obj)
 484 {
 485     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 486
 487     object_property_add(obj, "guest-stats", "guest statistics",
 488                         balloon_stats_get_all, NULL, NULL, s, NULL);
 489
 490     object_property_add(obj, "guest-stats-polling-interval", "int",
 491                         balloon_stats_get_poll_interval,
 492                         balloon_stats_set_poll_interval,
 493                         NULL, s, NULL);
 494 }
 495
 496 static const VMStateDescription vmstate_virtio_balloon = {
 497     .name = "virtio-balloon",
 498     .minimum_version_id = 1,
 499     .version_id = 1,
 500     .fields = (VMStateField[]) {
 501         VMSTATE_VIRTIO_DEVICE,
 502         VMSTATE_END_OF_LIST()
 503     },
 504 };
 505
 506 static Property virtio_balloon_properties[] = {
 507     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 508                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 509     DEFINE_PROP_END_OF_LIST(),
 510 };
 511
 512 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 513 {
 514     DeviceClass *dc = DEVICE_CLASS(klass);
 515     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 516
 517     dc->props = virtio_balloon_properties;
 518     dc->vmsd = &vmstate_virtio_balloon;
 519     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 520     vdc->realize = virtio_balloon_device_realize;
 521     vdc->unrealize = virtio_balloon_device_unrealize;
 522     vdc->reset = virtio_balloon_device_reset;
 523     vdc->get_config = virtio_balloon_get_config;
 524     vdc->set_config = virtio_balloon_set_config;
 525     vdc->get_features = virtio_balloon_get_features;
 526     vdc->set_status = virtio_balloon_set_status;
 527     vdc->vmsd = &vmstate_virtio_balloon_device;
 528 }
 529
 530 static const TypeInfo virtio_balloon_info = {
 531     .name = TYPE_VIRTIO_BALLOON,
 532     .parent = TYPE_VIRTIO_DEVICE,
 533     .instance_size = sizeof(VirtIOBalloon),
 534     .instance_init = virtio_balloon_instance_init,
 535     .class_init = virtio_balloon_class_init,
 536 };
 537
 538 static void virtio_register_types(void)
 539 {
 540     type_register_static(&virtio_balloon_info);
 541 }
 542
 543 type_init(virtio_register_types)