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, 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, name, NULL, "guest-stats", 0, &err);
 124     if (err) {
 125         goto out;
 126     }
 127     visit_type_int(v, "last-update", &s->stats_last_update, &err);
 128     if (err) {
 129         goto out_end;
 130     }
 131
 132     visit_start_struct(v, "stats", NULL, NULL, 0, &err);
 133     if (err) {
 134         goto out_end;
 135     }
 136     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
 137         visit_type_uint64(v, balloon_stat_names[i], &s->stats[i], &err);
 138         if (err) {
 139             break;
 140         }
 141     }
 142     error_propagate(errp, err);
 143     err = NULL;
 144     visit_end_struct(v, &err);
 145
 146 out_end:
 147     error_propagate(errp, err);
 148     err = NULL;
 149     visit_end_struct(v, &err);
 150 out:
 151     error_propagate(errp, err);
 152 }
 153
 154 static void balloon_stats_get_poll_interval(Object *obj, Visitor *v,
 155                                             void *opaque, const char *name,
 156                                             Error **errp)
 157 {
 158     VirtIOBalloon *s = opaque;
 159     visit_type_int(v, name, &s->stats_poll_interval, errp);
 160 }
 161
 162 static void balloon_stats_set_poll_interval(Object *obj, Visitor *v,
 163                                             void *opaque, const char *name,
 164                                             Error **errp)
 165 {
 166     VirtIOBalloon *s = opaque;
 167     Error *local_err = NULL;
 168     int64_t value;
 169
 170     visit_type_int(v, name, &value, &local_err);
 171     if (local_err) {
 172         error_propagate(errp, local_err);
 173         return;
 174     }
 175
 176     if (value < 0) {
 177         error_setg(errp, "timer value must be greater than zero");
 178         return;
 179     }
 180
 181     if (value > UINT32_MAX) {
 182         error_setg(errp, "timer value is too big");
 183         return;
 184     }
 185
 186     if (value == s->stats_poll_interval) {
 187         return;
 188     }
 189
 190     if (value == 0) {
 191         /* timer=0 disables the timer */
 192         balloon_stats_destroy_timer(s);
 193         return;
 194     }
 195
 196     if (balloon_stats_enabled(s)) {
 197         /* timer interval change */
 198         s->stats_poll_interval = value;
 199         balloon_stats_change_timer(s, value);
 200         return;
 201     }
 202
 203     /* create a new timer */
 204     g_assert(s->stats_timer == NULL);
 205     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 206     s->stats_poll_interval = value;
 207     balloon_stats_change_timer(s, 0);
 208 }
 209
 210 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 211 {
 212     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 213     VirtQueueElement *elem;
 214     MemoryRegionSection section;
 215
 216     for (;;) {
 217         size_t offset = 0;
 218         uint32_t pfn;
 219         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 220         if (!elem) {
 221             return;
 222         }
 223
 224         while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) {
 225             ram_addr_t pa;
 226             ram_addr_t addr;
 227             int p = virtio_ldl_p(vdev, &pfn);
 228
 229             pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT;
 230             offset += 4;
 231
 232             /* FIXME: remove get_system_memory(), but how? */
 233             section = memory_region_find(get_system_memory(), pa, 1);
 234             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 235                 continue;
 236
 237             trace_virtio_balloon_handle_output(memory_region_name(section.mr),
 238                                                pa);
 239             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 240                should be OK because we only want a single page.  */
 241             addr = section.offset_within_region;
 242             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 243                          !!(vq == s->dvq));
 244             memory_region_unref(section.mr);
 245         }
 246
 247         virtqueue_push(vq, elem, offset);
 248         virtio_notify(vdev, vq);
 249         g_free(elem);
 250     }
 251 }
 252
 253 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 254 {
 255     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 256     VirtQueueElement *elem;
 257     VirtIOBalloonStat stat;
 258     size_t offset = 0;
 259     qemu_timeval tv;
 260
 261     s->stats_vq_elem = elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 262     if (!elem) {
 263         goto out;
 264     }
 265
 266     /* Initialize the stats to get rid of any stale values.  This is only
 267      * needed to handle the case where a guest supports fewer stats than it
 268      * used to (ie. it has booted into an old kernel).
 269      */
 270     reset_stats(s);
 271
 272     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 273            == sizeof(stat)) {
 274         uint16_t tag = virtio_tswap16(vdev, stat.tag);
 275         uint64_t val = virtio_tswap64(vdev, stat.val);
 276
 277         offset += sizeof(stat);
 278         if (tag < VIRTIO_BALLOON_S_NR)
 279             s->stats[tag] = val;
 280     }
 281     s->stats_vq_offset = offset;
 282
 283     if (qemu_gettimeofday(&tv) < 0) {
 284         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 285         goto out;
 286     }
 287
 288     s->stats_last_update = tv.tv_sec;
 289
 290 out:
 291     if (balloon_stats_enabled(s)) {
 292         balloon_stats_change_timer(s, s->stats_poll_interval);
 293     }
 294 }
 295
 296 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 297 {
 298     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 299     struct virtio_balloon_config config;
 300
 301     config.num_pages = cpu_to_le32(dev->num_pages);
 302     config.actual = cpu_to_le32(dev->actual);
 303
 304     trace_virtio_balloon_get_config(config.num_pages, config.actual);
 305     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 306 }
 307
 308 static void virtio_balloon_set_config(VirtIODevice *vdev,
 309                                       const uint8_t *config_data)
 310 {
 311     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 312     struct virtio_balloon_config config;
 313     uint32_t oldactual = dev->actual;
 314     ram_addr_t vm_ram_size = get_current_ram_size();
 315
 316     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 317     dev->actual = le32_to_cpu(config.actual);
 318     if (dev->actual != oldactual) {
 319         qapi_event_send_balloon_change(vm_ram_size -
 320                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 321                         &error_abort);
 322     }
 323     trace_virtio_balloon_set_config(dev->actual, oldactual);
 324 }
 325
 326 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f,
 327                                             Error **errp)
 328 {
 329     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 330     f |= dev->host_features;
 331     virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ);
 332     return f;
 333 }
 334
 335 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 336 {
 337     VirtIOBalloon *dev = opaque;
 338     info->actual = get_current_ram_size() - ((uint64_t) dev->actual <<
 339                                              VIRTIO_BALLOON_PFN_SHIFT);
 340 }
 341
 342 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 343 {
 344     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 345     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 346     ram_addr_t vm_ram_size = get_current_ram_size();
 347
 348     if (target > vm_ram_size) {
 349         target = vm_ram_size;
 350     }
 351     if (target) {
 352         dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 353         virtio_notify_config(vdev);
 354     }
 355     trace_virtio_balloon_to_target(target, dev->num_pages);
 356 }
 357
 358 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 359 {
 360     virtio_save(VIRTIO_DEVICE(opaque), f);
 361 }
 362
 363 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
 364 {
 365     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 366
 367     qemu_put_be32(f, s->num_pages);
 368     qemu_put_be32(f, s->actual);
 369 }
 370
 371 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 372 {
 373     if (version_id != 1)
 374         return -EINVAL;
 375
 376     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 377 }
 378
 379 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
 380                                       int version_id)
 381 {
 382     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 383
 384     s->num_pages = qemu_get_be32(f);
 385     s->actual = qemu_get_be32(f);
 386     return 0;
 387 }
 388
 389 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 390 {
 391     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 392     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 393     int ret;
 394
 395     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 396                 sizeof(struct virtio_balloon_config));
 397
 398     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 399                                    virtio_balloon_stat, s);
 400
 401     if (ret < 0) {
 402         error_setg(errp, "Only one balloon device is supported");
 403         virtio_cleanup(vdev);
 404         return;
 405     }
 406
 407     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 408     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 409     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 410
 411     reset_stats(s);
 412
 413     register_savevm(dev, "virtio-balloon", -1, 1,
 414                     virtio_balloon_save, virtio_balloon_load, s);
 415 }
 416
 417 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 418 {
 419     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 420     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 421
 422     balloon_stats_destroy_timer(s);
 423     qemu_remove_balloon_handler(s);
 424     unregister_savevm(dev, "virtio-balloon", s);
 425     virtio_cleanup(vdev);
 426 }
 427
 428 static void virtio_balloon_instance_init(Object *obj)
 429 {
 430     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 431
 432     object_property_add(obj, "guest-stats", "guest statistics",
 433                         balloon_stats_get_all, NULL, NULL, s, NULL);
 434
 435     object_property_add(obj, "guest-stats-polling-interval", "int",
 436                         balloon_stats_get_poll_interval,
 437                         balloon_stats_set_poll_interval,
 438                         NULL, s, NULL);
 439 }
 440
 441 static Property virtio_balloon_properties[] = {
 442     DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features,
 443                     VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false),
 444     DEFINE_PROP_END_OF_LIST(),
 445 };
 446
 447 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 448 {
 449     DeviceClass *dc = DEVICE_CLASS(klass);
 450     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 451
 452     dc->props = virtio_balloon_properties;
 453     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 454     vdc->realize = virtio_balloon_device_realize;
 455     vdc->unrealize = virtio_balloon_device_unrealize;
 456     vdc->get_config = virtio_balloon_get_config;
 457     vdc->set_config = virtio_balloon_set_config;
 458     vdc->get_features = virtio_balloon_get_features;
 459     vdc->save = virtio_balloon_save_device;
 460     vdc->load = virtio_balloon_load_device;
 461 }
 462
 463 static const TypeInfo virtio_balloon_info = {
 464     .name = TYPE_VIRTIO_BALLOON,
 465     .parent = TYPE_VIRTIO_DEVICE,
 466     .instance_size = sizeof(VirtIOBalloon),
 467     .instance_init = virtio_balloon_instance_init,
 468     .class_init = virtio_balloon_class_init,
 469 };
 470
 471 static void virtio_register_types(void)
 472 {
 473     type_register_static(&virtio_balloon_info);
 474 }
 475
 476 type_init(virtio_register_types)