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
  28 #if defined(__linux__)
  29 #include <sys/mman.h>
  30 #endif
  31
  32 #include "hw/virtio/virtio-bus.h"
  33
  34 static void balloon_page(void *addr, int deflate)
  35 {
  36 #if defined(__linux__)
  37     if (!kvm_enabled() || kvm_has_sync_mmu())
  38         qemu_madvise(addr, TARGET_PAGE_SIZE,
  39                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
  40 #endif
  41 }
  42
  43 static const char *balloon_stat_names[] = {
  44    [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
  45    [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
  46    [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
  47    [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
  48    [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
  49    [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
  50    [VIRTIO_BALLOON_S_NR] = NULL
  51 };
  52
  53 /*
  54  * reset_stats - Mark all items in the stats array as unset
  55  *
  56  * This function needs to be called at device initialization and before
  57  * updating to a set of newly-generated stats.  This will ensure that no
  58  * stale values stick around in case the guest reports a subset of the supported
  59  * statistics.
  60  */
  61 static inline void reset_stats(VirtIOBalloon *dev)
  62 {
  63     int i;
  64     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
  65 }
  66
  67 static bool balloon_stats_supported(const VirtIOBalloon *s)
  68 {
  69     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  70     return vdev->guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
  71 }
  72
  73 static bool balloon_stats_enabled(const VirtIOBalloon *s)
  74 {
  75     return s->stats_poll_interval > 0;
  76 }
  77
  78 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
  79 {
  80     if (balloon_stats_enabled(s)) {
  81         timer_del(s->stats_timer);
  82         timer_free(s->stats_timer);
  83         s->stats_timer = NULL;
  84         s->stats_poll_interval = 0;
  85     }
  86 }
  87
  88 static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
  89 {
  90     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
  91 }
  92
  93 static void balloon_stats_poll_cb(void *opaque)
  94 {
  95     VirtIOBalloon *s = opaque;
  96     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  97
  98     if (!balloon_stats_supported(s)) {
  99         /* re-schedule */
 100         balloon_stats_change_timer(s, s->stats_poll_interval);
 101         return;
 102     }
 103
 104     virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
 105     virtio_notify(vdev, s->svq);
 106 }
 107
 108 static void balloon_stats_get_all(Object *obj, struct Visitor *v,
 109                                   void *opaque, const char *name, Error **errp)
 110 {
 111     Error *err = NULL;
 112     VirtIOBalloon *s = opaque;
 113     int i;
 114
 115     if (!s->stats_last_update) {
 116         error_setg(errp, "guest hasn't updated any stats yet");
 117         return;
 118     }
 119
 120     visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
 121     if (err) {
 122         goto out;
 123     }
 124
 125     visit_type_int(v, &s->stats_last_update, "last-update", &err);
 126
 127     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
 128     if (err) {
 129         goto out_end;
 130     }
 131
 132     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
 133         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
 134                          &err);
 135     }
 136     visit_end_struct(v, &err);
 137
 138 out_end:
 139     visit_end_struct(v, &err);
 140
 141 out:
 142     error_propagate(errp, err);
 143 }
 144
 145 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
 146                                             void *opaque, const char *name,
 147                                             Error **errp)
 148 {
 149     VirtIOBalloon *s = opaque;
 150     visit_type_int(v, &s->stats_poll_interval, name, errp);
 151 }
 152
 153 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
 154                                             void *opaque, const char *name,
 155                                             Error **errp)
 156 {
 157     VirtIOBalloon *s = opaque;
 158     Error *local_err = NULL;
 159     int64_t value;
 160
 161     visit_type_int(v, &value, name, &local_err);
 162     if (local_err) {
 163         error_propagate(errp, local_err);
 164         return;
 165     }
 166
 167     if (value < 0) {
 168         error_setg(errp, "timer value must be greater than zero");
 169         return;
 170     }
 171
 172     if (value == s->stats_poll_interval) {
 173         return;
 174     }
 175
 176     if (value == 0) {
 177         /* timer=0 disables the timer */
 178         balloon_stats_destroy_timer(s);
 179         return;
 180     }
 181
 182     if (balloon_stats_enabled(s)) {
 183         /* timer interval change */
 184         s->stats_poll_interval = value;
 185         balloon_stats_change_timer(s, value);
 186         return;
 187     }
 188
 189     /* create a new timer */
 190     g_assert(s->stats_timer == NULL);
 191     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 192     s->stats_poll_interval = value;
 193     balloon_stats_change_timer(s, 0);
 194 }
 195
 196 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 197 {
 198     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 199     VirtQueueElement elem;
 200     MemoryRegionSection section;
 201
 202     while (virtqueue_pop(vq, &elem)) {
 203         size_t offset = 0;
 204         uint32_t pfn;
 205
 206         while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
 207             ram_addr_t pa;
 208             ram_addr_t addr;
 209
 210             pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
 211             offset += 4;
 212
 213             /* FIXME: remove get_system_memory(), but how? */
 214             section = memory_region_find(get_system_memory(), pa, 1);
 215             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 216                 continue;
 217
 218             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 219                should be OK because we only want a single page.  */
 220             addr = section.offset_within_region;
 221             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 222                          !!(vq == s->dvq));
 223             memory_region_unref(section.mr);
 224         }
 225
 226         virtqueue_push(vq, &elem, offset);
 227         virtio_notify(vdev, vq);
 228     }
 229 }
 230
 231 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 232 {
 233     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 234     VirtQueueElement *elem = &s->stats_vq_elem;
 235     VirtIOBalloonStat stat;
 236     size_t offset = 0;
 237     qemu_timeval tv;
 238
 239     if (!virtqueue_pop(vq, elem)) {
 240         goto out;
 241     }
 242
 243     /* Initialize the stats to get rid of any stale values.  This is only
 244      * needed to handle the case where a guest supports fewer stats than it
 245      * used to (ie. it has booted into an old kernel).
 246      */
 247     reset_stats(s);
 248
 249     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 250            == sizeof(stat)) {
 251         uint16_t tag = tswap16(stat.tag);
 252         uint64_t val = tswap64(stat.val);
 253
 254         offset += sizeof(stat);
 255         if (tag < VIRTIO_BALLOON_S_NR)
 256             s->stats[tag] = val;
 257     }
 258     s->stats_vq_offset = offset;
 259
 260     if (qemu_gettimeofday(&tv) < 0) {
 261         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 262         goto out;
 263     }
 264
 265     s->stats_last_update = tv.tv_sec;
 266
 267 out:
 268     if (balloon_stats_enabled(s)) {
 269         balloon_stats_change_timer(s, s->stats_poll_interval);
 270     }
 271 }
 272
 273 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 274 {
 275     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 276     struct virtio_balloon_config config;
 277
 278     config.num_pages = cpu_to_le32(dev->num_pages);
 279     config.actual = cpu_to_le32(dev->actual);
 280
 281     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 282 }
 283
 284 static void virtio_balloon_set_config(VirtIODevice *vdev,
 285                                       const uint8_t *config_data)
 286 {
 287     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 288     struct virtio_balloon_config config;
 289     uint32_t oldactual = dev->actual;
 290     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 291     dev->actual = le32_to_cpu(config.actual);
 292     if (dev->actual != oldactual) {
 293         qemu_balloon_changed(ram_size -
 294                        ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
 295     }
 296 }
 297
 298 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
 299 {
 300     f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
 301     return f;
 302 }
 303
 304 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 305 {
 306     VirtIOBalloon *dev = opaque;
 307     info->actual = ram_size - ((uint64_t) dev->actual <<
 308                                VIRTIO_BALLOON_PFN_SHIFT);
 309 }
 310
 311 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 312 {
 313     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 314     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 315
 316     if (target > ram_size) {
 317         target = ram_size;
 318     }
 319     if (target) {
 320         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 321         virtio_notify_config(vdev);
 322     }
 323 }
 324
 325 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 326 {
 327     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 328     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 329
 330     virtio_save(vdev, f);
 331
 332     qemu_put_be32(f, s->num_pages);
 333     qemu_put_be32(f, s->actual);
 334 }
 335
 336 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 337 {
 338     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 339     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 340     int ret;
 341
 342     if (version_id != 1)
 343         return -EINVAL;
 344
 345     ret = virtio_load(vdev, f);
 346     if (ret) {
 347         return ret;
 348     }
 349
 350     s->num_pages = qemu_get_be32(f);
 351     s->actual = qemu_get_be32(f);
 352     return 0;
 353 }
 354
 355 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 356 {
 357     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 358     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 359     int ret;
 360
 361     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 362                 sizeof(struct virtio_balloon_config));
 363
 364     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 365                                    virtio_balloon_stat, s);
 366
 367     if (ret < 0) {
 368         error_setg(errp, "Adding balloon handler failed");
 369         virtio_cleanup(vdev);
 370         return;
 371     }
 372
 373     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 374     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 375     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 376
 377     register_savevm(dev, "virtio-balloon", -1, 1,
 378                     virtio_balloon_save, virtio_balloon_load, s);
 379
 380     object_property_add(OBJECT(dev), "guest-stats", "guest statistics",
 381                         balloon_stats_get_all, NULL, NULL, s, NULL);
 382
 383     object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int",
 384                         balloon_stats_get_poll_interval,
 385                         balloon_stats_set_poll_interval,
 386                         NULL, s, NULL);
 387 }
 388
 389 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 390 {
 391     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 392     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 393
 394     balloon_stats_destroy_timer(s);
 395     qemu_remove_balloon_handler(s);
 396     unregister_savevm(dev, "virtio-balloon", s);
 397     virtio_cleanup(vdev);
 398 }
 399
 400 static Property virtio_balloon_properties[] = {
 401     DEFINE_PROP_END_OF_LIST(),
 402 };
 403
 404 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 405 {
 406     DeviceClass *dc = DEVICE_CLASS(klass);
 407     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 408
 409     dc->props = virtio_balloon_properties;
 410     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 411     vdc->realize = virtio_balloon_device_realize;
 412     vdc->unrealize = virtio_balloon_device_unrealize;
 413     vdc->get_config = virtio_balloon_get_config;
 414     vdc->set_config = virtio_balloon_set_config;
 415     vdc->get_features = virtio_balloon_get_features;
 416 }
 417
 418 static const TypeInfo virtio_balloon_info = {
 419     .name = TYPE_VIRTIO_BALLOON,
 420     .parent = TYPE_VIRTIO_DEVICE,
 421     .instance_size = sizeof(VirtIOBalloon),
 422     .class_init = virtio_balloon_class_init,
 423 };
 424
 425 static void virtio_register_types(void)
 426 {
 427     type_register_static(&virtio_balloon_info);
 428 }
 429
 430 type_init(virtio_register_types)