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/osdep.h" 17 #include "qemu/iov.h" 18 #include "qemu/timer.h" 19 #include "qemu-common.h" 20 #include "hw/virtio/virtio.h" 21 #include "hw/i386/pc.h" 22 #include "cpu.h" 23 #include "sysemu/balloon.h" 24 #include "hw/virtio/virtio-balloon.h" 25 #include "sysemu/kvm.h" 26 #include "exec/address-spaces.h" 27 #include "qapi/visitor.h" 28 #include "qapi-event.h" 29 #include "trace.h" 30 31 #if defined(__linux__) 32 #include <sys/mman.h> 33 #endif 34 35 #include "hw/virtio/virtio-bus.h" 36 #include "hw/virtio/virtio-access.h" 37 38 static void balloon_page(void *addr, int deflate) 39 { 40 #if defined(__linux__) 41 if (!qemu_balloon_is_inhibited() && (!kvm_enabled() || 42 kvm_has_sync_mmu())) { 43 qemu_madvise(addr, TARGET_PAGE_SIZE, 44 deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED); 45 } 46 #endif 47 } 48 49 static const char *balloon_stat_names[] = { 50 [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in", 51 [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out", 52 [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults", 53 [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults", 54 [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory", 55 [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory", 56 [VIRTIO_BALLOON_S_NR] = NULL 57 }; 58 59 /* 60 * reset_stats - Mark all items in the stats array as unset 61 * 62 * This function needs to be called at device initialization and before 63 * updating to a set of newly-generated stats. This will ensure that no 64 * stale values stick around in case the guest reports a subset of the supported 65 * statistics. 66 */ 67 static inline void reset_stats(VirtIOBalloon *dev) 68 { 69 int i; 70 for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1); 71 } 72 73 static bool balloon_stats_supported(const VirtIOBalloon *s) 74 { 75 VirtIODevice *vdev = VIRTIO_DEVICE(s); 76 return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); 77 } 78 79 static bool balloon_stats_enabled(const VirtIOBalloon *s) 80 { 81 return s->stats_poll_interval > 0; 82 } 83 84 static void balloon_stats_destroy_timer(VirtIOBalloon *s) 85 { 86 if (balloon_stats_enabled(s)) { 87 timer_del(s->stats_timer); 88 timer_free(s->stats_timer); 89 s->stats_timer = NULL; 90 s->stats_poll_interval = 0; 91 } 92 } 93 94 static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs) 95 { 96 timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000); 97 } 98 99 static void balloon_stats_poll_cb(void *opaque) 100 { 101 VirtIOBalloon *s = opaque; 102 VirtIODevice *vdev = VIRTIO_DEVICE(s); 103 104 if (!balloon_stats_supported(s)) { 105 /* re-schedule */ 106 balloon_stats_change_timer(s, s->stats_poll_interval); 107 return; 108 } 109 110 virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset); 111 virtio_notify(vdev, s->svq); 112 } 113 114 static void balloon_stats_get_all(Object *obj, struct Visitor *v, 115 void *opaque, const char *name, Error **errp) 116 { 117 Error *err = NULL; 118 VirtIOBalloon *s = opaque; 119 int i; 120 121 visit_start_struct(v, NULL, "guest-stats", name, 0, &err); 122 if (err) { 123 goto out; 124 } 125 visit_type_int(v, &s->stats_last_update, "last-update", &err); 126 if (err) { 127 goto out_end; 128 } 129 130 visit_start_struct(v, NULL, NULL, "stats", 0, &err); 131 if (err) { 132 goto out_end; 133 } 134 for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) { 135 visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i], 136 &err); 137 } 138 error_propagate(errp, err); 139 err = NULL; 140 visit_end_struct(v, &err); 141 142 out_end: 143 error_propagate(errp, err); 144 err = NULL; 145 visit_end_struct(v, &err); 146 out: 147 error_propagate(errp, err); 148 } 149 150 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v, 151 void *opaque, const char *name, 152 Error **errp) 153 { 154 VirtIOBalloon *s = opaque; 155 visit_type_int(v, &s->stats_poll_interval, name, errp); 156 } 157 158 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v, 159 void *opaque, const char *name, 160 Error **errp) 161 { 162 VirtIOBalloon *s = opaque; 163 Error *local_err = NULL; 164 int64_t value; 165 166 visit_type_int(v, &value, name, &local_err); 167 if (local_err) { 168 error_propagate(errp, local_err); 169 return; 170 } 171 172 if (value < 0) { 173 error_setg(errp, "timer value must be greater than zero"); 174 return; 175 } 176 177 if (value > UINT32_MAX) { 178 error_setg(errp, "timer value is too big"); 179 return; 180 } 181 182 if (value == s->stats_poll_interval) { 183 return; 184 } 185 186 if (value == 0) { 187 /* timer=0 disables the timer */ 188 balloon_stats_destroy_timer(s); 189 return; 190 } 191 192 if (balloon_stats_enabled(s)) { 193 /* timer interval change */ 194 s->stats_poll_interval = value; 195 balloon_stats_change_timer(s, value); 196 return; 197 } 198 199 /* create a new timer */ 200 g_assert(s->stats_timer == NULL); 201 s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); 202 s->stats_poll_interval = value; 203 balloon_stats_change_timer(s, 0); 204 } 205 206 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 207 { 208 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 209 VirtQueueElement elem; 210 MemoryRegionSection section; 211 212 while (virtqueue_pop(vq, &elem)) { 213 size_t offset = 0; 214 uint32_t pfn; 215 216 while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) { 217 ram_addr_t pa; 218 ram_addr_t addr; 219 int p = virtio_ldl_p(vdev, &pfn); 220 221 pa = (ram_addr_t) p << VIRTIO_BALLOON_PFN_SHIFT; 222 offset += 4; 223 224 /* FIXME: remove get_system_memory(), but how? */ 225 section = memory_region_find(get_system_memory(), pa, 1); 226 if (!int128_nz(section.size) || !memory_region_is_ram(section.mr)) 227 continue; 228 229 trace_virtio_balloon_handle_output(memory_region_name(section.mr), 230 pa); 231 /* Using memory_region_get_ram_ptr is bending the rules a bit, but 232 should be OK because we only want a single page. */ 233 addr = section.offset_within_region; 234 balloon_page(memory_region_get_ram_ptr(section.mr) + addr, 235 !!(vq == s->dvq)); 236 memory_region_unref(section.mr); 237 } 238 239 virtqueue_push(vq, &elem, offset); 240 virtio_notify(vdev, vq); 241 } 242 } 243 244 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) 245 { 246 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 247 VirtQueueElement *elem = &s->stats_vq_elem; 248 VirtIOBalloonStat stat; 249 size_t offset = 0; 250 qemu_timeval tv; 251 252 if (!virtqueue_pop(vq, elem)) { 253 goto out; 254 } 255 256 /* Initialize the stats to get rid of any stale values. This is only 257 * needed to handle the case where a guest supports fewer stats than it 258 * used to (ie. it has booted into an old kernel). 259 */ 260 reset_stats(s); 261 262 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) 263 == sizeof(stat)) { 264 uint16_t tag = virtio_tswap16(vdev, stat.tag); 265 uint64_t val = virtio_tswap64(vdev, stat.val); 266 267 offset += sizeof(stat); 268 if (tag < VIRTIO_BALLOON_S_NR) 269 s->stats[tag] = val; 270 } 271 s->stats_vq_offset = offset; 272 273 if (qemu_gettimeofday(&tv) < 0) { 274 fprintf(stderr, "warning: %s: failed to get time of day\n", __func__); 275 goto out; 276 } 277 278 s->stats_last_update = tv.tv_sec; 279 280 out: 281 if (balloon_stats_enabled(s)) { 282 balloon_stats_change_timer(s, s->stats_poll_interval); 283 } 284 } 285 286 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) 287 { 288 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 289 struct virtio_balloon_config config; 290 291 config.num_pages = cpu_to_le32(dev->num_pages); 292 config.actual = cpu_to_le32(dev->actual); 293 294 trace_virtio_balloon_get_config(config.num_pages, config.actual); 295 memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); 296 } 297 298 static void virtio_balloon_set_config(VirtIODevice *vdev, 299 const uint8_t *config_data) 300 { 301 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 302 struct virtio_balloon_config config; 303 uint32_t oldactual = dev->actual; 304 ram_addr_t vm_ram_size = get_current_ram_size(); 305 306 memcpy(&config, config_data, sizeof(struct virtio_balloon_config)); 307 dev->actual = le32_to_cpu(config.actual); 308 if (dev->actual != oldactual) { 309 qapi_event_send_balloon_change(vm_ram_size - 310 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT), 311 &error_abort); 312 } 313 trace_virtio_balloon_set_config(dev->actual, oldactual); 314 } 315 316 static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, 317 Error **errp) 318 { 319 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 320 f |= dev->host_features; 321 virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); 322 return f; 323 } 324 325 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 326 { 327 VirtIOBalloon *dev = opaque; 328 info->actual = get_current_ram_size() - ((uint64_t) dev->actual << 329 VIRTIO_BALLOON_PFN_SHIFT); 330 } 331 332 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 333 { 334 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 335 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 336 ram_addr_t vm_ram_size = get_current_ram_size(); 337 338 if (target > vm_ram_size) { 339 target = vm_ram_size; 340 } 341 if (target) { 342 dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 343 virtio_notify_config(vdev); 344 } 345 trace_virtio_balloon_to_target(target, dev->num_pages); 346 } 347 348 static void virtio_balloon_save(QEMUFile *f, void *opaque) 349 { 350 virtio_save(VIRTIO_DEVICE(opaque), f); 351 } 352 353 static void virtio_balloon_save_device(VirtIODevice *vdev, QEMUFile *f) 354 { 355 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 356 357 qemu_put_be32(f, s->num_pages); 358 qemu_put_be32(f, s->actual); 359 } 360 361 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) 362 { 363 if (version_id != 1) 364 return -EINVAL; 365 366 return virtio_load(VIRTIO_DEVICE(opaque), f, version_id); 367 } 368 369 static int virtio_balloon_load_device(VirtIODevice *vdev, QEMUFile *f, 370 int version_id) 371 { 372 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 373 374 s->num_pages = qemu_get_be32(f); 375 s->actual = qemu_get_be32(f); 376 return 0; 377 } 378 379 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 380 { 381 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 382 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 383 int ret; 384 385 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 386 sizeof(struct virtio_balloon_config)); 387 388 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 389 virtio_balloon_stat, s); 390 391 if (ret < 0) { 392 error_setg(errp, "Only one balloon device is supported"); 393 virtio_cleanup(vdev); 394 return; 395 } 396 397 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 398 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 399 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 400 401 reset_stats(s); 402 403 register_savevm(dev, "virtio-balloon", -1, 1, 404 virtio_balloon_save, virtio_balloon_load, s); 405 } 406 407 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp) 408 { 409 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 410 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 411 412 balloon_stats_destroy_timer(s); 413 qemu_remove_balloon_handler(s); 414 unregister_savevm(dev, "virtio-balloon", s); 415 virtio_cleanup(vdev); 416 } 417 418 static void virtio_balloon_instance_init(Object *obj) 419 { 420 VirtIOBalloon *s = VIRTIO_BALLOON(obj); 421 422 object_property_add(obj, "guest-stats", "guest statistics", 423 balloon_stats_get_all, NULL, NULL, s, NULL); 424 425 object_property_add(obj, "guest-stats-polling-interval", "int", 426 balloon_stats_get_poll_interval, 427 balloon_stats_set_poll_interval, 428 NULL, s, NULL); 429 } 430 431 static Property virtio_balloon_properties[] = { 432 DEFINE_PROP_BIT("deflate-on-oom", VirtIOBalloon, host_features, 433 VIRTIO_BALLOON_F_DEFLATE_ON_OOM, false), 434 DEFINE_PROP_END_OF_LIST(), 435 }; 436 437 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 438 { 439 DeviceClass *dc = DEVICE_CLASS(klass); 440 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 441 442 dc->props = virtio_balloon_properties; 443 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 444 vdc->realize = virtio_balloon_device_realize; 445 vdc->unrealize = virtio_balloon_device_unrealize; 446 vdc->get_config = virtio_balloon_get_config; 447 vdc->set_config = virtio_balloon_set_config; 448 vdc->get_features = virtio_balloon_get_features; 449 vdc->save = virtio_balloon_save_device; 450 vdc->load = virtio_balloon_load_device; 451 } 452 453 static const TypeInfo virtio_balloon_info = { 454 .name = TYPE_VIRTIO_BALLOON, 455 .parent = TYPE_VIRTIO_DEVICE, 456 .instance_size = sizeof(VirtIOBalloon), 457 .instance_init = virtio_balloon_instance_init, 458 .class_init = virtio_balloon_class_init, 459 }; 460 461 static void virtio_register_types(void) 462 { 463 type_register_static(&virtio_balloon_info); 464 } 465 466 type_init(virtio_register_types) 467