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     g_free(s->stats_vq_elem);
 113     s->stats_vq_elem = NULL;
 114 }
 115
 116 static void balloon_stats_get_all(Object *obj, struct Visitor *v,
 117                                   void *opaque, const char *name, Error **errp)
 118 {
 119     Error *err = NULL;
 120     VirtIOBalloon *s = opaque;
 121     int i;
 122
 123     visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
 124     if (err) {
 125         goto out;
 126     }
 127     visit_type_int(v, &s->stats_last_update, "last-update", &err);
 128     if (err) {
 129         goto out_end;
 130     }
 131
 132     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
 133     if (err) {
 134         goto out_end;
 135     }
 136     for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
 137         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
 138                          &err);
 139     }
 140     error_propagate(errp, err);
 141     err = NULL;
 142     visit_end_struct(v, &err);
 143
 144 out_end:
 145     error_propagate(errp, err);
 146     err = NULL;
 147     visit_end_struct(v, &err);
 148 out:
 149     error_propagate(errp, err);
 150 }
 151
 152 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
 153                                             void *opaque, const char *name,
 154                                             Error **errp)
 155 {
 156     VirtIOBalloon *s = opaque;
 157     visit_type_int(v, &s->stats_poll_interval, name, errp);
 158 }
 159
 160 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
 161                                             void *opaque, const char *name,
 162                                             Error **errp)
 163 {
 164     VirtIOBalloon *s = opaque;
 165     Error *local_err = NULL;
 166     int64_t value;
 167
 168     visit_type_int(v, &value, name, &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) || !memory_region_is_ram(section.mr))
 233                 continue;
 234
 235             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 236                                                pa);
 237             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 238                should be OK because we only want a single page.  */
 239             addr = section.offset_within_region;
 240             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 241                          !!(vq == s->dvq));
 242             memory_region_unref(section.mr);
 243         }
 244
 245         virtqueue_push(vq, elem, offset);
 246         virtio_notify(vdev, vq);
 247         g_free(elem);
 248     }
 249 }
 250
 251 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 252 {
 253     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 254     VirtQueueElement *elem;
 255     VirtIOBalloonStat stat;
 256     size_t offset = 0;
 257     qemu_timeval tv;
 258
 259     s->stats_vq_elem = elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 260     if (!elem) {
 261         goto out;
 262     }
 263
 264     /* Initialize the stats to get rid of any stale values.  This is only
 265      * needed to handle the case where a guest supports fewer stats than it
 266      * used to (ie. it has booted into an old kernel).
 267      */
 268     reset_stats(s);
 269
 270     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 271            == sizeof(stat)) {
 272         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 273         uint64_t val = virtio_tswap64(vdev, stat.val);
 274
 275         offset += sizeof(stat);
 276         if (tag < VIRTIO_BALLOON_S_NR)
 277             s->stats[tag] = val;
 278     }
 279     s->stats_vq_offset = offset;
 280
 281     if (qemu_gettimeofday(&tv) < 0) {
 282         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 283         goto out;
 284     }
 285
 286     s->stats_last_update = tv.tv_sec;
 287
 288 out:
 289     if (balloon_stats_enabled(s)) {
 290         balloon_stats_change_timer(s, s->stats_poll_interval);
 291     }
 292 }
 293
 294 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 295 {
 296     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 297     struct virtio_balloon_config config;
 298
 299     config.num_pages = cpu_to_le32(dev->num_pages);
 300     config.actual = cpu_to_le32(dev->actual);
 301
 302     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 303     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 304 }
 305
 306 static void virtio_balloon_set_config(VirtIODevice *vdev,
 307                                       const uint8_t *config_data)
 308 {
 309     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 310     struct virtio_balloon_config config;
 311     uint32_t oldactual = dev->actual;
 312     ram_addr_t vm_ram_size = get_current_ram_size();
 313
 314     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 315     dev->actual = le32_to_cpu(config.actual);
 316     if (dev->actual != oldactual) {
 317         qapi_event_send_balloon_change(vm_ram_size -
 318                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 319                         &error_abort);
 320     }
 321     trace_virtio_balloon_set_config(dev->actual, oldactual);
 322 }
 323
 324 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 325                                             Error **errp)
 326 {
 327     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 328     f |= dev->host_features;
 329     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 330     return f;
 331 }
 332
 333 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 334 {
 335     VirtIOBalloon *dev = opaque;
 336     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 337                                              VIRTIO_BALLOON_PFN_SHIFT);
 338 }
 339
 340 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 341 {
 342     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 343     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 344     ram_addr_t vm_ram_size = get_current_ram_size();
 345
 346     if (target > vm_ram_size) {
 347         target = vm_ram_size;
 348     }
 349     if (target) {
 350         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 351         virtio_notify_config(vdev);
 352     }
 353     trace_virtio_balloon_to_target(target, dev->num_pages);
 354 }
 355
 356 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 357 {
 358     virtio_save(VIRTIO_DEVICE(opaque), f);
 359 }
 360
 361 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
 362 {
 363     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 364
 365     qemu_put_be32(f, s->num_pages);
 366     qemu_put_be32(f, s->actual);
 367 }
 368
 369 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 370 {
 371     if (version_id != 1)
 372         return -EINVAL;
 373
 374     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 375 }
 376
 377 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
 378                                       int version_id)
 379 {
 380     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 381
 382     s->num_pages = qemu_get_be32(f);
 383     s->actual = qemu_get_be32(f);
 384     return 0;
 385 }
 386
 387 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 388 {
 389     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 390     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 391     int ret;
 392
 393     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 394                 sizeof(struct virtio_balloon_config));
 395
 396     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 397                                    virtio_balloon_stat, s);
 398
 399     if (ret < 0) {
 400         error_setg(errp, "Only one balloon device is supported");
 401         virtio_cleanup(vdev);
 402         return;
 403     }
 404
 405     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 406     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 407     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 408
 409     reset_stats(s);
 410
 411     register_savevm(dev, "virtio-balloon", -1, 1,
 412                     virtio_balloon_save, virtio_balloon_load, s);
 413 }
 414
 415 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 416 {
 417     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 418     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 419
 420     balloon_stats_destroy_timer(s);
 421     qemu_remove_balloon_handler(s);
 422     unregister_savevm(dev, "virtio-balloon", s);
 423     virtio_cleanup(vdev);
 424 }
 425
 426 static void virtio_balloon_instance_init(Object *obj)
 427 {
 428     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 429
 430     object_property_add(obj, "guest-stats", "guest statistics",
 431                         balloon_stats_get_all, NULL, NULL, s, NULL);
 432
 433     object_property_add(obj, "guest-stats-polling-interval", "int",
 434                         balloon_stats_get_poll_interval,
 435                         balloon_stats_set_poll_interval,
 436                         NULL, s, NULL);
 437 }
 438
 439 static Property virtio_balloon_properties[] = {
 440     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 441                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 442     DEFINE_PROP_END_OF_LIST(),
 443 };
 444
 445 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 446 {
 447     DeviceClass *dc = DEVICE_CLASS(klass);
 448     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 449
 450     dc->props = virtio_balloon_properties;
 451     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 452     vdc->realize = virtio_balloon_device_realize;
 453     vdc->unrealize = virtio_balloon_device_unrealize;
 454     vdc->get_config = virtio_balloon_get_config;
 455     vdc->set_config = virtio_balloon_set_config;
 456     vdc->get_features = virtio_balloon_get_features;
 457     vdc->save = virtio_balloon_save_device;
 458     vdc->load = virtio_balloon_load_device;
 459 }
 460
 461 static const TypeInfo virtio_balloon_info = {
 462     .name = TYPE_VIRTIO_BALLOON,
 463     .parent = TYPE_VIRTIO_DEVICE,
 464     .instance_size = sizeof(VirtIOBalloon),
 465     .instance_init = virtio_balloon_instance_init,
 466     .class_init = virtio_balloon_class_init,
 467 };
 468
 469 static void virtio_register_types(void)
 470 {
 471     type_register_static(&virtio_balloon_info);
 472 }
 473
 474 type_init(virtio_register_types)