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     VirtIOBalloon *s = opaque;
 112     int i;
 113
 114     if (!s->stats_last_update) {
 115         error_setg(errp, "guest hasn't updated any stats yet");
 116         return;
 117     }
 118
 119     visit_start_struct(v, NULL, "guest-stats", name, 0, errp);
 120     visit_type_int(v, &s->stats_last_update, "last-update", errp);
 121
 122     visit_start_struct(v, NULL, NULL, "stats", 0, errp);
 123     for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
 124         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
 125                          errp);
 126     }
 127     visit_end_struct(v, errp);
 128
 129     visit_end_struct(v, errp);
 130 }
 131
 132 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
 133                                             void *opaque, const char *name,
 134                                             Error **errp)
 135 {
 136     VirtIOBalloon *s = opaque;
 137     visit_type_int(v, &s->stats_poll_interval, name, errp);
 138 }
 139
 140 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
 141                                             void *opaque, const char *name,
 142                                             Error **errp)
 143 {
 144     VirtIOBalloon *s = opaque;
 145     Error *local_err = NULL;
 146     int64_t value;
 147
 148     visit_type_int(v, &value, name, &local_err);
 149     if (local_err) {
 150         error_propagate(errp, local_err);
 151         return;
 152     }
 153
 154     if (value < 0) {
 155         error_setg(errp, "timer value must be greater than zero");
 156         return;
 157     }
 158
 159     if (value == s->stats_poll_interval) {
 160         return;
 161     }
 162
 163     if (value == 0) {
 164         /* timer=0 disables the timer */
 165         balloon_stats_destroy_timer(s);
 166         return;
 167     }
 168
 169     if (balloon_stats_enabled(s)) {
 170         /* timer interval change */
 171         s->stats_poll_interval = value;
 172         balloon_stats_change_timer(s, value);
 173         return;
 174     }
 175
 176     /* create a new timer */
 177     g_assert(s->stats_timer == NULL);
 178     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 179     s->stats_poll_interval = value;
 180     balloon_stats_change_timer(s, 0);
 181 }
 182
 183 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 184 {
 185     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 186     VirtQueueElement elem;
 187     MemoryRegionSection section;
 188
 189     while (virtqueue_pop(vq, &elem)) {
 190         size_t offset = 0;
 191         uint32_t pfn;
 192
 193         while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
 194             ram_addr_t pa;
 195             ram_addr_t addr;
 196
 197             pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
 198             offset += 4;
 199
 200             /* FIXME: remove get_system_memory(), but how? */
 201             section = memory_region_find(get_system_memory(), pa, 1);
 202             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 203                 continue;
 204
 205             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 206                should be OK because we only want a single page.  */
 207             addr = section.offset_within_region;
 208             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 209                          !!(vq == s->dvq));
 210             memory_region_unref(section.mr);
 211         }
 212
 213         virtqueue_push(vq, &elem, offset);
 214         virtio_notify(vdev, vq);
 215     }
 216 }
 217
 218 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 219 {
 220     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 221     VirtQueueElement *elem = &s->stats_vq_elem;
 222     VirtIOBalloonStat stat;
 223     size_t offset = 0;
 224     qemu_timeval tv;
 225
 226     if (!virtqueue_pop(vq, elem)) {
 227         goto out;
 228     }
 229
 230     /* Initialize the stats to get rid of any stale values.  This is only
 231      * needed to handle the case where a guest supports fewer stats than it
 232      * used to (ie. it has booted into an old kernel).
 233      */
 234     reset_stats(s);
 235
 236     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 237            == sizeof(stat)) {
 238         uint16_t tag = tswap16(stat.tag);
 239         uint64_t val = tswap64(stat.val);
 240
 241         offset += sizeof(stat);
 242         if (tag < VIRTIO_BALLOON_S_NR)
 243             s->stats[tag] = val;
 244     }
 245     s->stats_vq_offset = offset;
 246
 247     if (qemu_gettimeofday(&tv) < 0) {
 248         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 249         goto out;
 250     }
 251
 252     s->stats_last_update = tv.tv_sec;
 253
 254 out:
 255     if (balloon_stats_enabled(s)) {
 256         balloon_stats_change_timer(s, s->stats_poll_interval);
 257     }
 258 }
 259
 260 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 261 {
 262     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 263     struct virtio_balloon_config config;
 264
 265     config.num_pages = cpu_to_le32(dev->num_pages);
 266     config.actual = cpu_to_le32(dev->actual);
 267
 268     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 269 }
 270
 271 static void virtio_balloon_set_config(VirtIODevice *vdev,
 272                                       const uint8_t *config_data)
 273 {
 274     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 275     struct virtio_balloon_config config;
 276     uint32_t oldactual = dev->actual;
 277     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 278     dev->actual = le32_to_cpu(config.actual);
 279     if (dev->actual != oldactual) {
 280         qemu_balloon_changed(ram_size -
 281                        ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
 282     }
 283 }
 284
 285 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
 286 {
 287     f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
 288     return f;
 289 }
 290
 291 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 292 {
 293     VirtIOBalloon *dev = opaque;
 294     info->actual = ram_size - ((uint64_t) dev->actual <<
 295                                VIRTIO_BALLOON_PFN_SHIFT);
 296 }
 297
 298 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 299 {
 300     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 301     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 302
 303     if (target > ram_size) {
 304         target = ram_size;
 305     }
 306     if (target) {
 307         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 308         virtio_notify_config(vdev);
 309     }
 310 }
 311
 312 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 313 {
 314     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 315     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 316
 317     virtio_save(vdev, f);
 318
 319     qemu_put_be32(f, s->num_pages);
 320     qemu_put_be32(f, s->actual);
 321 }
 322
 323 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 324 {
 325     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 326     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 327     int ret;
 328
 329     if (version_id != 1)
 330         return -EINVAL;
 331
 332     ret = virtio_load(vdev, f);
 333     if (ret) {
 334         return ret;
 335     }
 336
 337     s->num_pages = qemu_get_be32(f);
 338     s->actual = qemu_get_be32(f);
 339     return 0;
 340 }
 341
 342 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 343 {
 344     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 345     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 346     int ret;
 347
 348     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 349                 sizeof(struct virtio_balloon_config));
 350
 351     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 352                                    virtio_balloon_stat, s);
 353
 354     if (ret < 0) {
 355         error_setg(errp, "Adding balloon handler failed");
 356         virtio_cleanup(vdev);
 357         return;
 358     }
 359
 360     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 361     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 362     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 363
 364     register_savevm(dev, "virtio-balloon", -1, 1,
 365                     virtio_balloon_save, virtio_balloon_load, s);
 366
 367     object_property_add(OBJECT(dev), "guest-stats", "guest statistics",
 368                         balloon_stats_get_all, NULL, NULL, s, NULL);
 369
 370     object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int",
 371                         balloon_stats_get_poll_interval,
 372                         balloon_stats_set_poll_interval,
 373                         NULL, s, NULL);
 374 }
 375
 376 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 377 {
 378     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 379     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 380
 381     balloon_stats_destroy_timer(s);
 382     qemu_remove_balloon_handler(s);
 383     unregister_savevm(dev, "virtio-balloon", s);
 384     virtio_cleanup(vdev);
 385 }
 386
 387 static Property virtio_balloon_properties[] = {
 388     DEFINE_PROP_END_OF_LIST(),
 389 };
 390
 391 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 392 {
 393     DeviceClass *dc = DEVICE_CLASS(klass);
 394     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 395
 396     dc->props = virtio_balloon_properties;
 397     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 398     vdc->realize = virtio_balloon_device_realize;
 399     vdc->unrealize = virtio_balloon_device_unrealize;
 400     vdc->get_config = virtio_balloon_get_config;
 401     vdc->set_config = virtio_balloon_set_config;
 402     vdc->get_features = virtio_balloon_get_features;
 403 }
 404
 405 static const TypeInfo virtio_balloon_info = {
 406     .name = TYPE_VIRTIO_BALLOON,
 407     .parent = TYPE_VIRTIO_DEVICE,
 408     .instance_size = sizeof(VirtIOBalloon),
 409     .class_init = virtio_balloon_class_init,
 410 };
 411
 412 static void virtio_register_types(void)
 413 {
 414     type_register_static(&virtio_balloon_info);
 415 }
 416
 417 type_init(virtio_register_types)