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     visit_start_struct(v, NULL, "guest-stats", name, 0, &err);
 116     if (err) {
 117         goto out;
 118     }
 119     visit_type_int(v, &s->stats_last_update, "last-update", &err);
 120     if (err) {
 121         goto out_end;
 122     }
 123
 124     visit_start_struct(v, NULL, NULL, "stats", 0, &err);
 125     if (err) {
 126         goto out_end;
 127     }
 128     for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) {
 129         visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
 130                          &err);
 131     }
 132     error_propagate(errp, err);
 133     err = NULL;
 134     visit_end_struct(v, &err);
 135
 136 out_end:
 137     error_propagate(errp, err);
 138     err = NULL;
 139     visit_end_struct(v, &err);
 140 out:
 141     error_propagate(errp, err);
 142 }
 143
 144 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
 145                                             void *opaque, const char *name,
 146                                             Error **errp)
 147 {
 148     VirtIOBalloon *s = opaque;
 149     visit_type_int(v, &s->stats_poll_interval, name, errp);
 150 }
 151
 152 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
 153                                             void *opaque, const char *name,
 154                                             Error **errp)
 155 {
 156     VirtIOBalloon *s = opaque;
 157     Error *local_err = NULL;
 158     int64_t value;
 159
 160     visit_type_int(v, &value, name, &local_err);
 161     if (local_err) {
 162         error_propagate(errp, local_err);
 163         return;
 164     }
 165
 166     if (value < 0) {
 167         error_setg(errp, "timer value must be greater than zero");
 168         return;
 169     }
 170
 171     if (value == s->stats_poll_interval) {
 172         return;
 173     }
 174
 175     if (value == 0) {
 176         /* timer=0 disables the timer */
 177         balloon_stats_destroy_timer(s);
 178         return;
 179     }
 180
 181     if (balloon_stats_enabled(s)) {
 182         /* timer interval change */
 183         s->stats_poll_interval = value;
 184         balloon_stats_change_timer(s, value);
 185         return;
 186     }
 187
 188     /* create a new timer */
 189     g_assert(s->stats_timer == NULL);
 190     s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s);
 191     s->stats_poll_interval = value;
 192     balloon_stats_change_timer(s, 0);
 193 }
 194
 195 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 196 {
 197     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 198     VirtQueueElement elem;
 199     MemoryRegionSection section;
 200
 201     while (virtqueue_pop(vq, &elem)) {
 202         size_t offset = 0;
 203         uint32_t pfn;
 204
 205         while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
 206             ram_addr_t pa;
 207             ram_addr_t addr;
 208
 209             pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
 210             offset += 4;
 211
 212             /* FIXME: remove get_system_memory(), but how? */
 213             section = memory_region_find(get_system_memory(), pa, 1);
 214             if (!int128_nz(section.size) || !memory_region_is_ram(section.mr))
 215                 continue;
 216
 217             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 218                should be OK because we only want a single page.  */
 219             addr = section.offset_within_region;
 220             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 221                          !!(vq == s->dvq));
 222             memory_region_unref(section.mr);
 223         }
 224
 225         virtqueue_push(vq, &elem, offset);
 226         virtio_notify(vdev, vq);
 227     }
 228 }
 229
 230 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 231 {
 232     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 233     VirtQueueElement *elem = &s->stats_vq_elem;
 234     VirtIOBalloonStat stat;
 235     size_t offset = 0;
 236     qemu_timeval tv;
 237
 238     if (!virtqueue_pop(vq, elem)) {
 239         goto out;
 240     }
 241
 242     /* Initialize the stats to get rid of any stale values.  This is only
 243      * needed to handle the case where a guest supports fewer stats than it
 244      * used to (ie. it has booted into an old kernel).
 245      */
 246     reset_stats(s);
 247
 248     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 249            == sizeof(stat)) {
 250         uint16_t tag = tswap16(stat.tag);
 251         uint64_t val = tswap64(stat.val);
 252
 253         offset += sizeof(stat);
 254         if (tag < VIRTIO_BALLOON_S_NR)
 255             s->stats[tag] = val;
 256     }
 257     s->stats_vq_offset = offset;
 258
 259     if (qemu_gettimeofday(&tv) < 0) {
 260         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 261         goto out;
 262     }
 263
 264     s->stats_last_update = tv.tv_sec;
 265
 266 out:
 267     if (balloon_stats_enabled(s)) {
 268         balloon_stats_change_timer(s, s->stats_poll_interval);
 269     }
 270 }
 271
 272 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 273 {
 274     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 275     struct virtio_balloon_config config;
 276
 277     config.num_pages = cpu_to_le32(dev->num_pages);
 278     config.actual = cpu_to_le32(dev->actual);
 279
 280     memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
 281 }
 282
 283 static void virtio_balloon_set_config(VirtIODevice *vdev,
 284                                       const uint8_t *config_data)
 285 {
 286     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 287     struct virtio_balloon_config config;
 288     uint32_t oldactual = dev->actual;
 289     memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
 290     dev->actual = le32_to_cpu(config.actual);
 291     if (dev->actual != oldactual) {
 292         qemu_balloon_changed(ram_size -
 293                        ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
 294     }
 295 }
 296
 297 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
 298 {
 299     f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
 300     return f;
 301 }
 302
 303 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 304 {
 305     VirtIOBalloon *dev = opaque;
 306     info->actual = ram_size - ((uint64_t) dev->actual <<
 307                                VIRTIO_BALLOON_PFN_SHIFT);
 308 }
 309
 310 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 311 {
 312     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 313     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 314
 315     if (target > ram_size) {
 316         target = ram_size;
 317     }
 318     if (target) {
 319         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 320         virtio_notify_config(vdev);
 321     }
 322 }
 323
 324 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 325 {
 326     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 327     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 328
 329     virtio_save(vdev, f);
 330
 331     qemu_put_be32(f, s->num_pages);
 332     qemu_put_be32(f, s->actual);
 333 }
 334
 335 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 336 {
 337     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 338     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 339     int ret;
 340
 341     if (version_id != 1)
 342         return -EINVAL;
 343
 344     ret = virtio_load(vdev, f);
 345     if (ret) {
 346         return ret;
 347     }
 348
 349     s->num_pages = qemu_get_be32(f);
 350     s->actual = qemu_get_be32(f);
 351     return 0;
 352 }
 353
 354 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
 355 {
 356     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 357     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 358     int ret;
 359
 360     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON,
 361                 sizeof(struct virtio_balloon_config));
 362
 363     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 364                                    virtio_balloon_stat, s);
 365
 366     if (ret < 0) {
 367         error_setg(errp, "Adding balloon handler failed");
 368         virtio_cleanup(vdev);
 369         return;
 370     }
 371
 372     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 373     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 374     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 375
 376     reset_stats(s);
 377
 378     register_savevm(dev, "virtio-balloon", -1, 1,
 379                     virtio_balloon_save, virtio_balloon_load, s);
 380
 381     object_property_add(OBJECT(dev), "guest-stats", "guest statistics",
 382                         balloon_stats_get_all, NULL, NULL, s, NULL);
 383
 384     object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int",
 385                         balloon_stats_get_poll_interval,
 386                         balloon_stats_set_poll_interval,
 387                         NULL, s, NULL);
 388 }
 389
 390 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp)
 391 {
 392     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 393     VirtIOBalloon *s = VIRTIO_BALLOON(dev);
 394
 395     balloon_stats_destroy_timer(s);
 396     qemu_remove_balloon_handler(s);
 397     unregister_savevm(dev, "virtio-balloon", s);
 398     virtio_cleanup(vdev);
 399 }
 400
 401 static Property virtio_balloon_properties[] = {
 402     DEFINE_PROP_END_OF_LIST(),
 403 };
 404
 405 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 406 {
 407     DeviceClass *dc = DEVICE_CLASS(klass);
 408     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 409
 410     dc->props = virtio_balloon_properties;
 411     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 412     vdc->realize = virtio_balloon_device_realize;
 413     vdc->unrealize = virtio_balloon_device_unrealize;
 414     vdc->get_config = virtio_balloon_get_config;
 415     vdc->set_config = virtio_balloon_set_config;
 416     vdc->get_features = virtio_balloon_get_features;
 417 }
 418
 419 static const TypeInfo virtio_balloon_info = {
 420     .name = TYPE_VIRTIO_BALLOON,
 421     .parent = TYPE_VIRTIO_DEVICE,
 422     .instance_size = sizeof(VirtIOBalloon),
 423     .class_init = virtio_balloon_class_init,
 424 };
 425
 426 static void virtio_register_types(void)
 427 {
 428     type_register_static(&virtio_balloon_info);
 429 }
 430
 431 type_init(virtio_register_types)