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 "cpu.h"
  23 #include "sysemu/balloon.h"
  24 #include "hw/virtio/virtio-balloon.h"
  25 #include "sysemu/kvm.h"
  26 #include "exec/address-spaces.h"
  27 #include "qapi/visitor.h"
  28 #include "qapi-event.h"
  29 #include "trace.h"
  30
  31 #if defined(__linux__)
  32 #include <sys/mman.h>
  33 #endif
  34
  35 #include "hw/virtio/virtio-bus.h"
  36 #include "hw/virtio/virtio-access.h"
  37
  38 static void balloon_page(void *addr, int deflate)
  39 {
  40 #if defined(__linux__)
  41     if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
  42                                          kvm_has_sync_mmu())) {
  43         qemu_madvise(addr, TARGET_PAGE_SIZE,
  44                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
  45     }
  46 #endif
  47 }
  48
  49 static const char *balloon_stat_names[] = {
  50    [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
  51    [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
  52    [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
  53    [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
  54    [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
  55    [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
  56    [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory",
  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             break;
 141         }
 142     }
 143     error_propagate(errp, err);
 144     err = NULL;
 145     visit_end_struct(v, &err);
 146
 147 out_end:
 148     error_propagate(errp, err);
 149     err = NULL;
 150     visit_end_struct(v, &err);
 151 out:
 152     error_propagate(errp, err);
 153 }
 154
 155 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v,
 156                                             const char *name, void *opaque,
 157                                             Error **errp)
 158 {
 159     VirtIOBalloon *s = opaque;
 160     visit_type_int(v, name, &s->stats_poll_interval, errp);
 161 }
 162
 163 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
 164                                             const char *name, void *opaque,
 165                                             Error **errp)
 166 {
 167     VirtIOBalloon *s = opaque;
 168     Error *local_err = NULL;
 169     int64_t value;
 170
 171     visit_type_int(v, name, &value, &local_err);
 172     if (local_err) {
 173         error_propagate(errp, local_err);
 174         return;
 175     }
 176
 177     if (value < 0) {
 178         error_setg(errp, "timer value must be greater than zero");
 179         return;
 180     }
 181
 182     if (value > UINT32_MAX) {
 183         error_setg(errp, "timer value is too big");
 184         return;
 185     }
 186
 187     if (value == s->stats_poll_interval) {
 188         return;
 189     }
 190
 191     if (value == 0) {
 192         /* timer=0 disables the timer */
 193         balloon_stats_destroy_timer(s);
 194         return;
 195     }
 196
 197     if (balloon_stats_enabled(s)) {
 198         /* timer interval change */
 199         s->stats_poll_interval = value;
 200         balloon_stats_change_timer(s, value);
 201         return;
 202     }
 203
 204     /* create a new timer */
 205     g_assert(s->stats_timer == NULL);
 206     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 207     s->stats_poll_interval = value;
 208     balloon_stats_change_timer(s, 0);
 209 }
 210
 211 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 212 {
 213     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 214     VirtQueueElement *elem;
 215     MemoryRegionSection section;
 216
 217     for (;;) {
 218         size_t offset = 0;
 219         uint32_t pfn;
 220         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 221         if (!elem) {
 222             return;
 223         }
 224
 225         while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) {
 226             ram_addr_t pa;
 227             ram_addr_t addr;
 228             int p = virtio_ldl_p(vdev, &pfn);
 229
 230             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 231             offset += 4;
 232
 233             /* FIXME: remove get_system_memory(), but how? */
 234             section = memory_region_find(get_system_memory(), pa, 1);
 235             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 236                 continue;
 237
 238             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 239                                                pa);
 240             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 241                should be OK because we only want a single page.  */
 242             addr = section.offset_within_region;
 243             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 244                          !!(vq == s->dvq));
 245             memory_region_unref(section.mr);
 246         }
 247
 248         virtqueue_push(vq, elem, offset);
 249         virtio_notify(vdev, vq);
 250         g_free(elem);
 251     }
 252 }
 253
 254 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 255 {
 256     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 257     VirtQueueElement *elem;
 258     VirtIOBalloonStat stat;
 259     size_t offset = 0;
 260     qemu_timeval tv;
 261
 262     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 263     if (!elem) {
 264         goto out;
 265     }
 266
 267     if (s->stats_vq_elem != NULL) {
 268         /* This should never happen if the driver follows the spec. */
 269         virtqueue_push(vq, s->stats_vq_elem, 0);
 270         virtio_notify(vdev, vq);
 271         g_free(s->stats_vq_elem);
 272     }
 273
 274     s->stats_vq_elem = elem;
 275
 276     /* Initialize the stats to get rid of any stale values.  This is only
 277      * needed to handle the case where a guest supports fewer stats than it
 278      * used to (ie. it has booted into an old kernel).
 279      */
 280     reset_stats(s);
 281
 282     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 283            == sizeof(stat)) {
 284         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 285         uint64_t val = virtio_tswap64(vdev, stat.val);
 286
 287         offset += sizeof(stat);
 288         if (tag < VIRTIO_BALLOON_S_NR)
 289             s->stats[tag] = val;
 290     }
 291     s->stats_vq_offset = offset;
 292
 293     if (qemu_gettimeofday(&tv) < 0) {
 294         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 295         goto out;
 296     }
 297
 298     s->stats_last_update = tv.tv_sec;
 299
 300 out:
 301     if (balloon_stats_enabled(s)) {
 302         balloon_stats_change_timer(s, s->stats_poll_interval);
 303     }
 304 }
 305
 306 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 307 {
 308     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 309     struct virtio_balloon_config config;
 310
 311     config.num_pages = cpu_to_le32(dev->num_pages);
 312     config.actual = cpu_to_le32(dev->actual);
 313
 314     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 315     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 316 }
 317
 318 static int build_dimm_list(Object *obj, void *opaque)
 319 {
 320     GSList **list = opaque;
 321
 322     if (object_dynamic_cast(obj, TYPE_PC_DIMM)) {
 323         DeviceState *dev = DEVICE(obj);
 324         if (dev->realized) { /* only realized DIMMs matter */
 325             *list = g_slist_prepend(*list, dev);
 326         }
 327     }
 328
 329     object_child_foreach(obj, build_dimm_list, opaque);
 330     return 0;
 331 }
 332
 333 static ram_addr_t get_current_ram_size(void)
 334 {
 335     GSList *list = NULL, *item;
 336     ram_addr_t size = ram_size;
 337
 338     build_dimm_list(qdev_get_machine(), &list);
 339     for (item = list; item; item = g_slist_next(item)) {
 340         Object *obj = OBJECT(item->data);
 341         if (!strcmp(object_get_typename(obj), TYPE_PC_DIMM)) {
 342             size += object_property_get_int(obj, PC_DIMM_SIZE_PROP,
 343                                             &error_abort);
 344         }
 345     }
 346     g_slist_free(list);
 347
 348     return size;
 349 }
 350
 351 static void virtio_balloon_set_config(VirtIODevice *vdev,
 352                                       const uint8_t *config_data)
 353 {
 354     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 355     struct virtio_balloon_config config;
 356     uint32_t oldactual = dev->actual;
 357     ram_addr_t vm_ram_size = get_current_ram_size();
 358
 359     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 360     dev->actual = le32_to_cpu(config.actual);
 361     if (dev->actual != oldactual) {
 362         qapi_event_send_balloon_change(vm_ram_size -
 363                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 364                         &error_abort);
 365     }
 366     trace_virtio_balloon_set_config(dev->actual, oldactual);
 367 }
 368
 369 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 370                                             Error **errp)
 371 {
 372     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 373     f |= dev->host_features;
 374     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 375     return f;
 376 }
 377
 378 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 379 {
 380     VirtIOBalloon *dev = opaque;
 381     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 382                                              VIRTIO_BALLOON_PFN_SHIFT);
 383 }
 384
 385 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 386 {
 387     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 388     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 389     ram_addr_t vm_ram_size = get_current_ram_size();
 390
 391     if (target > vm_ram_size) {
 392         target = vm_ram_size;
 393     }
 394     if (target) {
 395         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 396         virtio_notify_config(vdev);
 397     }
 398     trace_virtio_balloon_to_target(target, dev->num_pages);
 399 }
 400
 401 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 402 {
 403     virtio_save(VIRTIO_DEVICE(opaque), f);
 404 }
 405
 406 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
 407 {
 408     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 409
 410     qemu_put_be32(f, s->num_pages);
 411     qemu_put_be32(f, s->actual);
 412 }
 413
 414 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 415 {
 416     if (version_id != 1)
 417         return -EINVAL;
 418
 419     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 420 }
 421
 422 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
 423                                       int version_id)
 424 {
 425     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 426
 427     s->num_pages = qemu_get_be32(f);
 428     s->actual = qemu_get_be32(f);
 429
 430     if (balloon_stats_enabled(s)) {
 431         balloon_stats_change_timer(s, s->stats_poll_interval);
 432     }
 433     return 0;
 434 }
 435
 436 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 437 {
 438     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 439     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 440     int ret;
 441
 442     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 443                 sizeof(struct virtio_balloon_config));
 444
 445     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 446                                    virtio_balloon_stat, s);
 447
 448     if (ret < 0) {
 449         error_setg(errp, "Only one balloon device is supported");
 450         virtio_cleanup(vdev);
 451         return;
 452     }
 453
 454     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 455     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 456     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 457
 458     reset_stats(s);
 459
 460     register_savevm(dev, "virtio-balloon", -1, 1,
 461                     virtio_balloon_save, virtio_balloon_load, s);
 462 }
 463
 464 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 465 {
 466     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 467     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 468
 469     balloon_stats_destroy_timer(s);
 470     qemu_remove_balloon_handler(s);
 471     unregister_savevm(dev, "virtio-balloon", s);
 472     virtio_cleanup(vdev);
 473 }
 474
 475 static void virtio_balloon_device_reset(VirtIODevice *vdev)
 476 {
 477     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 478
 479     if (s->stats_vq_elem != NULL) {
 480         g_free(s->stats_vq_elem);
 481         s->stats_vq_elem = NULL;
 482     }
 483 }
 484
 485 static void virtio_balloon_instance_init(Object *obj)
 486 {
 487     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 488
 489     object_property_add(obj, "guest-stats", "guest statistics",
 490                         balloon_stats_get_all, NULL, NULL, s, NULL);
 491
 492     object_property_add(obj, "guest-stats-polling-interval", "int",
 493                         balloon_stats_get_poll_interval,
 494                         balloon_stats_set_poll_interval,
 495                         NULL, s, NULL);
 496 }
 497
 498 static Property virtio_balloon_properties[] = {
 499     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 500                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 501     DEFINE_PROP_END_OF_LIST(),
 502 };
 503
 504 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 505 {
 506     DeviceClass *dc = DEVICE_CLASS(klass);
 507     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 508
 509     dc->props = virtio_balloon_properties;
 510     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 511     vdc->realize = virtio_balloon_device_realize;
 512     vdc->unrealize = virtio_balloon_device_unrealize;
 513     vdc->reset = virtio_balloon_device_reset;
 514     vdc->get_config = virtio_balloon_get_config;
 515     vdc->set_config = virtio_balloon_set_config;
 516     vdc->get_features = virtio_balloon_get_features;
 517     vdc->save = virtio_balloon_save_device;
 518     vdc->load = virtio_balloon_load_device;
 519 }
 520
 521 static const TypeInfo virtio_balloon_info = {
 522     .name = TYPE_VIRTIO_BALLOON,
 523     .parent = TYPE_VIRTIO_DEVICE,
 524     .instance_size = sizeof(VirtIOBalloon),
 525     .instance_init = virtio_balloon_instance_init,
 526     .class_init = virtio_balloon_class_init,
 527 };
 528
 529 static void virtio_register_types(void)
 530 {
 531     type_register_static(&virtio_balloon_info);
 532 }
 533
 534 type_init(virtio_register_types)