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_NR] = NULL
  57 };
  58
  59 /*
  60  * reset_stats - Mark all items in the stats array as unset
  61  *
  62  * This function needs to be called at device initialization and before
  63  * updating to a set of newly-generated stats.  This will ensure that no
  64  * stale values stick around in case the guest reports a subset of the supported
  65  * statistics.
  66  */
  67 static inline void reset_stats(VirtIOBalloon *dev)
  68 {
  69     int i;
  70     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
  71 }
  72
  73 static bool balloon_stats_supported(const VirtIOBalloon *s)
  74 {
  75     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  76     return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ);
  77 }
  78
  79 static bool balloon_stats_enabled(const VirtIOBalloon *s)
  80 {
  81     return s->stats_poll_interval > 0;
  82 }
  83
  84 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
  85 {
  86     if (balloon_stats_enabled(s)) {
  87         timer_del(s->stats_timer);
  88         timer_free(s->stats_timer);
  89         s->stats_timer = NULL;
  90         s->stats_poll_interval = 0;
  91     }
  92 }
  93
  94 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs)
  95 {
  96     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
  97 }
  98
  99 static void balloon_stats_poll_cb(void *opaque)
 100 {
 101     VirtIOBalloon *s = opaque;
 102     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 103
 104     if (!balloon_stats_supported(s)) {
 105         /* re-schedule */
 106         balloon_stats_change_timer(s, s->stats_poll_interval);
 107         return;
 108     }
 109
 110     virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
 111     virtio_notify(vdev, s->svq);
 112 }
 113
 114 static void balloon_stats_get_all(Object *obj, struct Visitor *v,
 115                                   void *opaque, const char *name, Error **errp)
 116 {
 117     Error *err = NULL;
 118     VirtIOBalloon *s = opaque;
 119     int i;
 120
 121     visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
 122     if (err) {
 123         goto out;
 124     }
 125     visit_type_int(v, &s->stats_last_update, "last-update", &err);
 126     if (err) {
 127         goto out_end;
 128     }
 129
 130     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
 131     if (err) {
 132         goto out_end;
 133     }
 134     for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
 135         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
 136                          &err);
 137     }
 138     error_propagate(errp, err);
 139     err = NULL;
 140     visit_end_struct(v, &err);
 141
 142 out_end:
 143     error_propagate(errp, err);
 144     err = NULL;
 145     visit_end_struct(v, &err);
 146 out:
 147     error_propagate(errp, err);
 148 }
 149
 150 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
 151                                             void *opaque, const char *name,
 152                                             Error **errp)
 153 {
 154     VirtIOBalloon *s = opaque;
 155     visit_type_int(v, &s->stats_poll_interval, name, errp);
 156 }
 157
 158 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
 159                                             void *opaque, const char *name,
 160                                             Error **errp)
 161 {
 162     VirtIOBalloon *s = opaque;
 163     Error *local_err = NULL;
 164     int64_t value;
 165
 166     visit_type_int(v, &value, name, &local_err);
 167     if (local_err) {
 168         error_propagate(errp, local_err);
 169         return;
 170     }
 171
 172     if (value < 0) {
 173         error_setg(errp, "timer value must be greater than zero");
 174         return;
 175     }
 176
 177     if (value > UINT32_MAX) {
 178         error_setg(errp, "timer value is too big");
 179         return;
 180     }
 181
 182     if (value == s->stats_poll_interval) {
 183         return;
 184     }
 185
 186     if (value == 0) {
 187         /* timer=0 disables the timer */
 188         balloon_stats_destroy_timer(s);
 189         return;
 190     }
 191
 192     if (balloon_stats_enabled(s)) {
 193         /* timer interval change */
 194         s->stats_poll_interval = value;
 195         balloon_stats_change_timer(s, value);
 196         return;
 197     }
 198
 199     /* create a new timer */
 200     g_assert(s->stats_timer == NULL);
 201     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 202     s->stats_poll_interval = value;
 203     balloon_stats_change_timer(s, 0);
 204 }
 205
 206 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 207 {
 208     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 209     VirtQueueElement elem;
 210     MemoryRegionSection section;
 211
 212     while (virtqueue_pop(vq, &elem)) {
 213         size_t offset = 0;
 214         uint32_t pfn;
 215
 216         while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
 217             ram_addr_t pa;
 218             ram_addr_t addr;
 219             int p = virtio_ldl_p(vdev, &pfn);
 220
 221             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 222             offset += 4;
 223
 224             /* FIXME: remove get_system_memory(), but how? */
 225             section = memory_region_find(get_system_memory(), pa, 1);
 226             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 227                 continue;
 228
 229             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 230                                                pa);
 231             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 232                should be OK because we only want a single page.  */
 233             addr = section.offset_within_region;
 234             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 235                          !!(vq == s->dvq));
 236             memory_region_unref(section.mr);
 237         }
 238
 239         virtqueue_push(vq, &elem, offset);
 240         virtio_notify(vdev, vq);
 241     }
 242 }
 243
 244 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 245 {
 246     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 247     VirtQueueElement *elem = &s->stats_vq_elem;
 248     VirtIOBalloonStat stat;
 249     size_t offset = 0;
 250     qemu_timeval tv;
 251
 252     if (!virtqueue_pop(vq, elem)) {
 253         goto out;
 254     }
 255
 256     /* Initialize the stats to get rid of any stale values.  This is only
 257      * needed to handle the case where a guest supports fewer stats than it
 258      * used to (ie. it has booted into an old kernel).
 259      */
 260     reset_stats(s);
 261
 262     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 263            == sizeof(stat)) {
 264         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 265         uint64_t val = virtio_tswap64(vdev, stat.val);
 266
 267         offset += sizeof(stat);
 268         if (tag < VIRTIO_BALLOON_S_NR)
 269             s->stats[tag] = val;
 270     }
 271     s->stats_vq_offset = offset;
 272
 273     if (qemu_gettimeofday(&tv) < 0) {
 274         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 275         goto out;
 276     }
 277
 278     s->stats_last_update = tv.tv_sec;
 279
 280 out:
 281     if (balloon_stats_enabled(s)) {
 282         balloon_stats_change_timer(s, s->stats_poll_interval);
 283     }
 284 }
 285
 286 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 287 {
 288     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 289     struct virtio_balloon_config config;
 290
 291     config.num_pages = cpu_to_le32(dev->num_pages);
 292     config.actual = cpu_to_le32(dev->actual);
 293
 294     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 295     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 296 }
 297
 298 static void virtio_balloon_set_config(VirtIODevice *vdev,
 299                                       const uint8_t *config_data)
 300 {
 301     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 302     struct virtio_balloon_config config;
 303     uint32_t oldactual = dev->actual;
 304     ram_addr_t vm_ram_size = get_current_ram_size();
 305
 306     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 307     dev->actual = le32_to_cpu(config.actual);
 308     if (dev->actual != oldactual) {
 309         qapi_event_send_balloon_change(vm_ram_size -
 310                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 311                         &error_abort);
 312     }
 313     trace_virtio_balloon_set_config(dev->actual, oldactual);
 314 }
 315
 316 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 317                                             Error **errp)
 318 {
 319     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 320     f |= dev->host_features;
 321     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 322     return f;
 323 }
 324
 325 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 326 {
 327     VirtIOBalloon *dev = opaque;
 328     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 329                                              VIRTIO_BALLOON_PFN_SHIFT);
 330 }
 331
 332 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 333 {
 334     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 335     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 336     ram_addr_t vm_ram_size = get_current_ram_size();
 337
 338     if (target > vm_ram_size) {
 339         target = vm_ram_size;
 340     }
 341     if (target) {
 342         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 343         virtio_notify_config(vdev);
 344     }
 345     trace_virtio_balloon_to_target(target, dev->num_pages);
 346 }
 347
 348 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 349 {
 350     virtio_save(VIRTIO_DEVICE(opaque), f);
 351 }
 352
 353 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
 354 {
 355     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 356
 357     qemu_put_be32(f, s->num_pages);
 358     qemu_put_be32(f, s->actual);
 359 }
 360
 361 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 362 {
 363     if (version_id != 1)
 364         return -EINVAL;
 365
 366     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 367 }
 368
 369 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
 370                                       int version_id)
 371 {
 372     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 373
 374     s->num_pages = qemu_get_be32(f);
 375     s->actual = qemu_get_be32(f);
 376     return 0;
 377 }
 378
 379 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 380 {
 381     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 382     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 383     int ret;
 384
 385     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 386                 sizeof(struct virtio_balloon_config));
 387
 388     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 389                                    virtio_balloon_stat, s);
 390
 391     if (ret < 0) {
 392         error_setg(errp, "Only one balloon device is supported");
 393         virtio_cleanup(vdev);
 394         return;
 395     }
 396
 397     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 398     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 399     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 400
 401     reset_stats(s);
 402
 403     register_savevm(dev, "virtio-balloon", -1, 1,
 404                     virtio_balloon_save, virtio_balloon_load, s);
 405 }
 406
 407 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 408 {
 409     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 410     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 411
 412     balloon_stats_destroy_timer(s);
 413     qemu_remove_balloon_handler(s);
 414     unregister_savevm(dev, "virtio-balloon", s);
 415     virtio_cleanup(vdev);
 416 }
 417
 418 static void virtio_balloon_instance_init(Object *obj)
 419 {
 420     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 421
 422     object_property_add(obj, "guest-stats", "guest statistics",
 423                         balloon_stats_get_all, NULL, NULL, s, NULL);
 424
 425     object_property_add(obj, "guest-stats-polling-interval", "int",
 426                         balloon_stats_get_poll_interval,
 427                         balloon_stats_set_poll_interval,
 428                         NULL, s, NULL);
 429 }
 430
 431 static Property virtio_balloon_properties[] = {
 432     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 433                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 434     DEFINE_PROP_END_OF_LIST(),
 435 };
 436
 437 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 438 {
 439     DeviceClass *dc = DEVICE_CLASS(klass);
 440     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 441
 442     dc->props = virtio_balloon_properties;
 443     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 444     vdc->realize = virtio_balloon_device_realize;
 445     vdc->unrealize = virtio_balloon_device_unrealize;
 446     vdc->get_config = virtio_balloon_get_config;
 447     vdc->set_config = virtio_balloon_set_config;
 448     vdc->get_features = virtio_balloon_get_features;
 449     vdc->save = virtio_balloon_save_device;
 450     vdc->load = virtio_balloon_load_device;
 451 }
 452
 453 static const TypeInfo virtio_balloon_info = {
 454     .name = TYPE_VIRTIO_BALLOON,
 455     .parent = TYPE_VIRTIO_DEVICE,
 456     .instance_size = sizeof(VirtIOBalloon),
 457     .instance_init = virtio_balloon_instance_init,
 458     .class_init = virtio_balloon_class_init,
 459 };
 460
 461 static void virtio_register_types(void)
 462 {
 463     type_register_static(&virtio_balloon_info);
 464 }
 465
 466 type_init(virtio_register_types)