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