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
  35 static void balloon_page(void *addr, int deflate)
  36 {
  37 #if defined(__linux__)
  38     if (!kvm_enabled() || kvm_has_sync_mmu())
  39         qemu_madvise(addr, TARGET_PAGE_SIZE,
  40                 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
  41 #endif
  42 }
  43
  44 static const char *balloon_stat_names[] = {
  45    [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
  46    [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
  47    [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
  48    [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
  49    [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
  50    [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
  51    [VIRTIO_BALLOON_S_NR] = NULL
  52 };
  53
  54 /*
  55  * reset_stats - Mark all items in the stats array as unset
  56  *
  57  * This function needs to be called at device initialization and before
  58  * updating to a set of newly-generated stats.  This will ensure that no
  59  * stale values stick around in case the guest reports a subset of the supported
  60  * statistics.
  61  */
  62 static inline void reset_stats(VirtIOBalloon *dev)
  63 {
  64     int i;
  65     for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
  66 }
  67
  68 static bool balloon_stats_supported(const VirtIOBalloon *s)
  69 {
  70     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  71     return vdev->guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
  72 }
  73
  74 static bool balloon_stats_enabled(const VirtIOBalloon *s)
  75 {
  76     return s->stats_poll_interval > 0;
  77 }
  78
  79 static void balloon_stats_destroy_timer(VirtIOBalloon *s)
  80 {
  81     if (balloon_stats_enabled(s)) {
  82         timer_del(s->stats_timer);
  83         timer_free(s->stats_timer);
  84         s->stats_timer = NULL;
  85         s->stats_poll_interval = 0;
  86     }
  87 }
  88
  89 static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
  90 {
  91     timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);
  92 }
  93
  94 static void balloon_stats_poll_cb(void *opaque)
  95 {
  96     VirtIOBalloon *s = opaque;
  97     VirtIODevice *vdev = VIRTIO_DEVICE(s);
  98
  99     if (!balloon_stats_supported(s)) {
 100         /* re-schedule */
 101         balloon_stats_change_timer(s, s->stats_poll_interval);
 102         return;
 103     }
 104
 105     virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
 106     virtio_notify(vdev, s->svq);
 107 }
 108
 109 static void balloon_stats_get_all(Object *obj, struct Visitor *v,
 110                                   void *opaque, const char *name, Error **errp)
 111 {
 112     Error *err = NULL;
 113     VirtIOBalloon *s = opaque;
 114     int i;
 115
 116     visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
 117     if (err) {
 118         goto out;
 119     }
 120     visit_type_int(v, &s->stats_last_update, "last-update", &err);
 121     if (err) {
 122         goto out_end;
 123     }
 124
 125     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
 126     if (err) {
 127         goto out_end;
 128     }
 129     for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
 130         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
 131                          &err);
 132     }
 133     error_propagate(errp, err);
 134     err = NULL;
 135     visit_end_struct(v, &err);
 136
 137 out_end:
 138     error_propagate(errp, err);
 139     err = NULL;
 140     visit_end_struct(v, &err);
 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         qapi_event_send_balloon_change(ram_size -
 294                         ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
 295                         &error_abort);
 296     }
 297 }
 298
 299 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
 300 {
 301     f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
 302     return f;
 303 }
 304
 305 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 306 {
 307     VirtIOBalloon *dev = opaque;
 308     info->actual = ram_size - ((uint64_t) dev->actual <<
 309                                VIRTIO_BALLOON_PFN_SHIFT);
 310 }
 311
 312 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 313 {
 314     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 315     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 316
 317     if (target > ram_size) {
 318         target = ram_size;
 319     }
 320     if (target) {
 321         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 322         virtio_notify_config(vdev);
 323     }
 324 }
 325
 326 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 327 {
 328     virtio_save(VIRTIO_DEVICE(opaque), f);
 329 }
 330
 331 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f)
 332 {
 333     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 334
 335     qemu_put_be32(f, s->num_pages);
 336     qemu_put_be32(f, s->actual);
 337 }
 338
 339 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 340 {
 341     if (version_id != 1)
 342         return -EINVAL;
 343
 344     return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
 345 }
 346
 347 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f,
 348                                       int version_id)
 349 {
 350     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 351
 352     s->num_pages = qemu_get_be32(f);
 353     s->actual = qemu_get_be32(f);
 354     return 0;
 355 }
 356
 357 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 358 {
 359     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 360     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 361     int ret;
 362
 363     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 364                 sizeof(struct virtio_balloon_config));
 365
 366     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 367                                    virtio_balloon_stat, s);
 368
 369     if (ret < 0) {
 370         error_setg(errp, "Adding balloon handler failed");
 371         virtio_cleanup(vdev);
 372         return;
 373     }
 374
 375     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 376     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 377     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 378
 379     reset_stats(s);
 380
 381     register_savevm(dev, "virtio-balloon", -1, 1,
 382                     virtio_balloon_save, virtio_balloon_load, s);
 383
 384     object_property_add(OBJECT(dev), "guest-stats", "guest statistics",
 385                         balloon_stats_get_all, NULL, NULL, s, NULL);
 386
 387     object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int",
 388                         balloon_stats_get_poll_interval,
 389                         balloon_stats_set_poll_interval,
 390                         NULL, s, NULL);
 391 }
 392
 393 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 394 {
 395     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 396     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 397
 398     balloon_stats_destroy_timer(s);
 399     qemu_remove_balloon_handler(s);
 400     unregister_savevm(dev, "virtio-balloon", s);
 401     virtio_cleanup(vdev);
 402 }
 403
 404 static Property virtio_balloon_properties[] = {
 405     DEFINE_PROP_END_OF_LIST(),
 406 };
 407
 408 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 409 {
 410     DeviceClass *dc = DEVICE_CLASS(klass);
 411     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 412
 413     dc->props = virtio_balloon_properties;
 414     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 415     vdc->realize = virtio_balloon_device_realize;
 416     vdc->unrealize = virtio_balloon_device_unrealize;
 417     vdc->get_config = virtio_balloon_get_config;
 418     vdc->set_config = virtio_balloon_set_config;
 419     vdc->get_features = virtio_balloon_get_features;
 420     vdc->save = virtio_balloon_save_device;
 421     vdc->load = virtio_balloon_load_device;
 422 }
 423
 424 static const TypeInfo virtio_balloon_info = {
 425     .name = TYPE_VIRTIO_BALLOON,
 426     .parent = TYPE_VIRTIO_DEVICE,
 427     .instance_size = sizeof(VirtIOBalloon),
 428     .class_init = virtio_balloon_class_init,
 429 };
 430
 431 static void virtio_register_types(void)
 432 {
 433     type_register_static(&virtio_balloon_info);
 434 }
 435
 436 type_init(virtio_register_types)