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/iov.h"
  17 #include "qemu/timer.h"
  18 #include "qemu-common.h"
  19 #include "hw/virtio/virtio.h"
  20 #include "hw/i386/pc.h"
  21 #include "cpu.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
  29 #if defined(__linux__)
  30 #include <sys/mman.h>
  31 #endif
  32
  33 #include "hw/virtio/virtio-bus.h"
  34 #include "hw/virtio/virtio-access.h"
  35
  36 static void balloon_page(void *addr, int deflate)
  37 {
  38 #if defined(__linux__)
  39     if (!kvm_enabled() || kvm_has_sync_mmu())
  40         qemu_madvise(addr, TARGET_PAGE_SIZE,
  41                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
  42 #endif
  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_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 vdev->guest_features & (1 << 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 (!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 }
 109
 110 static void balloon_stats_get_all(Object *obj, struct Visitor *v,
 111                                   void *opaque, const char *name, Error **errp)
 112 {
 113     Error *err = NULL;
 114     VirtIOBalloon *s = opaque;
 115     int i;
 116
 117     visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
 118     if (err) {
 119         goto out;
 120     }
 121     visit_type_int(v, &s->stats_last_update, "last-update", &err);
 122     if (err) {
 123         goto out_end;
 124     }
 125
 126     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
 127     if (err) {
 128         goto out_end;
 129     }
 130     for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
 131         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
 132                          &err);
 133     }
 134     error_propagate(errp, err);
 135     err = NULL;
 136     visit_end_struct(v, &err);
 137
 138 out_end:
 139     error_propagate(errp, err);
 140     err = NULL;
 141     visit_end_struct(v, &err);
 142 out:
 143     error_propagate(errp, err);
 144 }
 145
 146 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
 147                                             void *opaque, const char *name,
 148                                             Error **errp)
 149 {
 150     VirtIOBalloon *s = opaque;
 151     visit_type_int(v, &s->stats_poll_interval, name, errp);
 152 }
 153
 154 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
 155                                             void *opaque, const char *name,
 156                                             Error **errp)
 157 {
 158     VirtIOBalloon *s = opaque;
 159     Error *local_err = NULL;
 160     int64_t value;
 161
 162     visit_type_int(v, &value, name, &local_err);
 163     if (local_err) {
 164         error_propagate(errp, local_err);
 165         return;
 166     }
 167
 168     if (value < 0) {
 169         error_setg(errp, "timer value must be greater than zero");
 170         return;
 171     }
 172
 173     if (value > UINT32_MAX) {
 174         error_setg(errp, "timer value is too big");
 175         return;
 176     }
 177
 178     if (value == s->stats_poll_interval) {
 179         return;
 180     }
 181
 182     if (value == 0) {
 183         /* timer=0 disables the timer */
 184         balloon_stats_destroy_timer(s);
 185         return;
 186     }
 187
 188     if (balloon_stats_enabled(s)) {
 189         /* timer interval change */
 190         s->stats_poll_interval = value;
 191         balloon_stats_change_timer(s, value);
 192         return;
 193     }
 194
 195     /* create a new timer */
 196     g_assert(s->stats_timer == NULL);
 197     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 198     s->stats_poll_interval = value;
 199     balloon_stats_change_timer(s, 0);
 200 }
 201
 202 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 203 {
 204     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 205     VirtQueueElement elem;
 206     MemoryRegionSection section;
 207
 208     while (virtqueue_pop(vq, &elem)) {
 209         size_t offset = 0;
 210         uint32_t pfn;
 211
 212         while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
 213             ram_addr_t pa;
 214             ram_addr_t addr;
 215             int p = virtio_ldl_p(vdev, &pfn);
 216
 217             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 218             offset += 4;
 219
 220             /* FIXME: remove get_system_memory(), but how? */
 221             section = memory_region_find(get_system_memory(), pa, 1);
 222             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 223                 continue;
 224
 225             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 226                should be OK because we only want a single page.  */
 227             addr = section.offset_within_region;
 228             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 229                          !!(vq == s->dvq));
 230             memory_region_unref(section.mr);
 231         }
 232
 233         virtqueue_push(vq, &elem, offset);
 234         virtio_notify(vdev, vq);
 235     }
 236 }
 237
 238 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 239 {
 240     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 241     VirtQueueElement *elem = &s->stats_vq_elem;
 242     VirtIOBalloonStat stat;
 243     size_t offset = 0;
 244     qemu_timeval tv;
 245
 246     if (!virtqueue_pop(vq, elem)) {
 247         goto out;
 248     }
 249
 250     /* Initialize the stats to get rid of any stale values.  This is only
 251      * needed to handle the case where a guest supports fewer stats than it
 252      * used to (ie. it has booted into an old kernel).
 253      */
 254     reset_stats(s);
 255
 256     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 257            == sizeof(stat)) {
 258         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 259         uint64_t val = virtio_tswap64(vdev, stat.val);
 260
 261         offset += sizeof(stat);
 262         if (tag < VIRTIO_BALLOON_S_NR)
 263             s->stats[tag] = val;
 264     }
 265     s->stats_vq_offset = offset;
 266
 267     if (qemu_gettimeofday(&tv) < 0) {
 268         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 269         goto out;
 270     }
 271
 272     s->stats_last_update = tv.tv_sec;
 273
 274 out:
 275     if (balloon_stats_enabled(s)) {
 276         balloon_stats_change_timer(s, s->stats_poll_interval);
 277     }
 278 }
 279
 280 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 281 {
 282     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 283     struct virtio_balloon_config config;
 284
 285     config.num_pages = cpu_to_le32(dev->num_pages);
 286     config.actual = cpu_to_le32(dev->actual);
 287
 288     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 289 }
 290
 291 static void virtio_balloon_set_config(VirtIODevice *vdev,
 292                                       const uint8_t *config_data)
 293 {
 294     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 295     struct virtio_balloon_config config;
 296     uint32_t oldactual = dev->actual;
 297     ram_addr_t vm_ram_size = get_current_ram_size();
 298
 299     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 300     dev->actual = le32_to_cpu(config.actual);
 301     if (dev->actual != oldactual) {
 302         qapi_event_send_balloon_change(vm_ram_size -
 303                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 304                         &error_abort);
 305     }
 306 }
 307
 308 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
 309 {
 310     f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
 311     return f;
 312 }
 313
 314 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 315 {
 316     VirtIOBalloon *dev = opaque;
 317     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 318                                              VIRTIO_BALLOON_PFN_SHIFT);
 319 }
 320
 321 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 322 {
 323     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 324     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 325     ram_addr_t vm_ram_size = get_current_ram_size();
 326
 327     if (target > vm_ram_size) {
 328         target = vm_ram_size;
 329     }
 330     if (target) {
 331         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 332         virtio_notify_config(vdev);
 333     }
 334 }
 335
 336 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 337 {
 338     virtio_save(VIRTIO_DEVICE(opaque), f);
 339 }
 340
 341 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
 342 {
 343     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 344
 345     qemu_put_be32(f, s->num_pages);
 346     qemu_put_be32(f, s->actual);
 347 }
 348
 349 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 350 {
 351     if (version_id != 1)
 352         return -EINVAL;
 353
 354     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 355 }
 356
 357 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
 358                                       int version_id)
 359 {
 360     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 361
 362     s->num_pages = qemu_get_be32(f);
 363     s->actual = qemu_get_be32(f);
 364     return 0;
 365 }
 366
 367 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 368 {
 369     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 370     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 371     int ret;
 372
 373     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 374                 sizeof(struct virtio_balloon_config));
 375
 376     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 377                                    virtio_balloon_stat, s);
 378
 379     if (ret < 0) {
 380         error_setg(errp, "Adding balloon handler failed");
 381         virtio_cleanup(vdev);
 382         return;
 383     }
 384
 385     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 386     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 387     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 388
 389     reset_stats(s);
 390
 391     register_savevm(dev, "virtio-balloon", -1, 1,
 392                     virtio_balloon_save, virtio_balloon_load, s);
 393
 394     object_property_add(OBJECT(dev), "guest-stats", "guest statistics",
 395                         balloon_stats_get_all, NULL, NULL, s, NULL);
 396
 397     object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int",
 398                         balloon_stats_get_poll_interval,
 399                         balloon_stats_set_poll_interval,
 400                         NULL, s, NULL);
 401 }
 402
 403 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 404 {
 405     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 406     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 407
 408     balloon_stats_destroy_timer(s);
 409     qemu_remove_balloon_handler(s);
 410     unregister_savevm(dev, "virtio-balloon", s);
 411     virtio_cleanup(vdev);
 412 }
 413
 414 static Property virtio_balloon_properties[] = {
 415     DEFINE_PROP_END_OF_LIST(),
 416 };
 417
 418 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 419 {
 420     DeviceClass *dc = DEVICE_CLASS(klass);
 421     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 422
 423     dc->props = virtio_balloon_properties;
 424     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 425     vdc->realize = virtio_balloon_device_realize;
 426     vdc->unrealize = virtio_balloon_device_unrealize;
 427     vdc->get_config = virtio_balloon_get_config;
 428     vdc->set_config = virtio_balloon_set_config;
 429     vdc->get_features = virtio_balloon_get_features;
 430     vdc->save = virtio_balloon_save_device;
 431     vdc->load = virtio_balloon_load_device;
 432 }
 433
 434 static const TypeInfo virtio_balloon_info = {
 435     .name = TYPE_VIRTIO_BALLOON,
 436     .parent = TYPE_VIRTIO_DEVICE,
 437     .instance_size = sizeof(VirtIOBalloon),
 438     .class_init = virtio_balloon_class_init,
 439 };
 440
 441 static void virtio_register_types(void)
 442 {
 443     type_register_static(&virtio_balloon_info);
 444 }
 445
 446 type_init(virtio_register_types)