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 intialization and before
  57  * before 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         qemu_del_timer(s->stats_timer);
  82         qemu_free_timer(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     qemu_mod_timer(s->stats_timer, qemu_get_clock_ms(vm_clock) + 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     int64_t value;
 146
 147     visit_type_int(v, &value, name, errp);
 148     if (error_is_set(errp)) {
 149         return;
 150     }
 151
 152     if (value < 0) {
 153         error_setg(errp, "timer value must be greater than zero");
 154         return;
 155     }
 156
 157     if (value == s->stats_poll_interval) {
 158         return;
 159     }
 160
 161     if (value == 0) {
 162         /* timer=0 disables the timer */
 163         balloon_stats_destroy_timer(s);
 164         return;
 165     }
 166
 167     if (balloon_stats_enabled(s)) {
 168         /* timer interval change */
 169         s->stats_poll_interval = value;
 170         balloon_stats_change_timer(s, value);
 171         return;
 172     }
 173
 174     /* create a new timer */
 175     g_assert(s->stats_timer == NULL);
 176     s->stats_timer = qemu_new_timer_ms(vm_clock, balloon_stats_poll_cb, s);
 177     s->stats_poll_interval = value;
 178     balloon_stats_change_timer(s, 0);
 179 }
 180
 181 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 182 {
 183     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 184     VirtQueueElement elem;
 185     MemoryRegionSection section;
 186
 187     while (virtqueue_pop(vq, &elem)) {
 188         size_t offset = 0;
 189         uint32_t pfn;
 190
 191         while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) {
 192             ram_addr_t pa;
 193             ram_addr_t addr;
 194
 195             pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
 196             offset += 4;
 197
 198             /* FIXME: remove get_system_memory(), but how? */
 199             section = memory_region_find(get_system_memory(), pa, 1);
 200             if (!section.size || !memory_region_is_ram(section.mr))
 201                 continue;
 202
 203             /* Using memory_region_get_ram_ptr is bending the rules a bit, but
 204                should be OK because we only want a single page.  */
 205             addr = section.offset_within_region;
 206             balloon_page(memory_region_get_ram_ptr(section.mr) + addr,
 207                          !!(vq == s->dvq));
 208         }
 209
 210         virtqueue_push(vq, &elem, offset);
 211         virtio_notify(vdev, vq);
 212     }
 213 }
 214
 215 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
 216 {
 217     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 218     VirtQueueElement *elem = &s->stats_vq_elem;
 219     VirtIOBalloonStat stat;
 220     size_t offset = 0;
 221     qemu_timeval tv;
 222
 223     if (!virtqueue_pop(vq, elem)) {
 224         goto out;
 225     }
 226
 227     /* Initialize the stats to get rid of any stale values.  This is only
 228      * needed to handle the case where a guest supports fewer stats than it
 229      * used to (ie. it has booted into an old kernel).
 230      */
 231     reset_stats(s);
 232
 233     while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat))
 234            == sizeof(stat)) {
 235         uint16_t tag = tswap16(stat.tag);
 236         uint64_t val = tswap64(stat.val);
 237
 238         offset += sizeof(stat);
 239         if (tag < VIRTIO_BALLOON_S_NR)
 240             s->stats[tag] = val;
 241     }
 242     s->stats_vq_offset = offset;
 243
 244     if (qemu_gettimeofday(&tv) < 0) {
 245         fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
 246         goto out;
 247     }
 248
 249     s->stats_last_update = tv.tv_sec;
 250
 251 out:
 252     if (balloon_stats_enabled(s)) {
 253         balloon_stats_change_timer(s, s->stats_poll_interval);
 254     }
 255 }
 256
 257 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
 258 {
 259     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 260     struct virtio_balloon_config config;
 261
 262     config.num_pages = cpu_to_le32(dev->num_pages);
 263     config.actual = cpu_to_le32(dev->actual);
 264
 265     memcpy(config_data, &config, 8);
 266 }
 267
 268 static void virtio_balloon_set_config(VirtIODevice *vdev,
 269                                       const uint8_t *config_data)
 270 {
 271     VirtIOBalloon *dev = VIRTIO_BALLOON(vdev);
 272     struct virtio_balloon_config config;
 273     uint32_t oldactual = dev->actual;
 274     memcpy(&config, config_data, 8);
 275     dev->actual = le32_to_cpu(config.actual);
 276     if (dev->actual != oldactual) {
 277         qemu_balloon_changed(ram_size -
 278                        ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
 279     }
 280 }
 281
 282 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
 283 {
 284     f |= (1 << VIRTIO_BALLOON_F_STATS_VQ);
 285     return f;
 286 }
 287
 288 static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
 289 {
 290     VirtIOBalloon *dev = opaque;
 291     info->actual = ram_size - ((uint64_t) dev->actual <<
 292                                VIRTIO_BALLOON_PFN_SHIFT);
 293 }
 294
 295 static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
 296 {
 297     VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
 298     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 299
 300     if (target > ram_size) {
 301         target = ram_size;
 302     }
 303     if (target) {
 304         dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 305         virtio_notify_config(vdev);
 306     }
 307 }
 308
 309 static void virtio_balloon_save(QEMUFile *f, void *opaque)
 310 {
 311     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 312     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 313
 314     virtio_save(vdev, f);
 315
 316     qemu_put_be32(f, s->num_pages);
 317     qemu_put_be32(f, s->actual);
 318 }
 319
 320 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
 321 {
 322     VirtIOBalloon *s = VIRTIO_BALLOON(opaque);
 323     VirtIODevice *vdev = VIRTIO_DEVICE(s);
 324     int ret;
 325
 326     if (version_id != 1)
 327         return -EINVAL;
 328
 329     ret = virtio_load(vdev, f);
 330     if (ret) {
 331         return ret;
 332     }
 333
 334     s->num_pages = qemu_get_be32(f);
 335     s->actual = qemu_get_be32(f);
 336     return 0;
 337 }
 338
 339 static int virtio_balloon_device_init(VirtIODevice *vdev)
 340 {
 341     DeviceState *qdev = DEVICE(vdev);
 342     VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
 343     int ret;
 344
 345     virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 8);
 346
 347     ret = qemu_add_balloon_handler(virtio_balloon_to_target,
 348                                    virtio_balloon_stat, s);
 349
 350     if (ret < 0) {
 351         virtio_cleanup(VIRTIO_DEVICE(s));
 352         return -1;
 353     }
 354
 355     s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 356     s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
 357     s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
 358
 359     register_savevm(qdev, "virtio-balloon", -1, 1,
 360                     virtio_balloon_save, virtio_balloon_load, s);
 361
 362     object_property_add(OBJECT(qdev), "guest-stats", "guest statistics",
 363                         balloon_stats_get_all, NULL, NULL, s, NULL);
 364
 365     object_property_add(OBJECT(qdev), "guest-stats-polling-interval", "int",
 366                         balloon_stats_get_poll_interval,
 367                         balloon_stats_set_poll_interval,
 368                         NULL, s, NULL);
 369     return 0;
 370 }
 371
 372 static int virtio_balloon_device_exit(DeviceState *qdev)
 373 {
 374     VirtIOBalloon *s = VIRTIO_BALLOON(qdev);
 375     VirtIODevice *vdev = VIRTIO_DEVICE(qdev);
 376
 377     balloon_stats_destroy_timer(s);
 378     qemu_remove_balloon_handler(s);
 379     unregister_savevm(qdev, "virtio-balloon", s);
 380     virtio_cleanup(vdev);
 381     return 0;
 382 }
 383
 384 static Property virtio_balloon_properties[] = {
 385     DEFINE_PROP_END_OF_LIST(),
 386 };
 387
 388 static void virtio_balloon_class_init(ObjectClass *klass, void *data)
 389 {
 390     DeviceClass *dc = DEVICE_CLASS(klass);
 391     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 392     dc->exit = virtio_balloon_device_exit;
 393     dc->props = virtio_balloon_properties;
 394     vdc->init = virtio_balloon_device_init;
 395     vdc->get_config = virtio_balloon_get_config;
 396     vdc->set_config = virtio_balloon_set_config;
 397     vdc->get_features = virtio_balloon_get_features;
 398 }
 399
 400 static const TypeInfo virtio_balloon_info = {
 401     .name = TYPE_VIRTIO_BALLOON,
 402     .parent = TYPE_VIRTIO_DEVICE,
 403     .instance_size = sizeof(VirtIOBalloon),
 404     .class_init = virtio_balloon_class_init,
 405 };
 406
 407 static void virtio_register_types(void)
 408 {
 409     type_register_static(&virtio_balloon_info);
 410 }
 411
 412 type_init(virtio_register_types)