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 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 329 VirtIODevice *vdev = VIRTIO_DEVICE(s); 330 331 virtio_save(vdev, f); 332 333 qemu_put_be32(f, s->num_pages); 334 qemu_put_be32(f, s->actual); 335 } 336 337 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) 338 { 339 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 340 VirtIODevice *vdev = VIRTIO_DEVICE(s); 341 int ret; 342 343 if (version_id != 1) 344 return -EINVAL; 345 346 ret = virtio_load(vdev, f, version_id); 347 if (ret) { 348 return ret; 349 } 350 351 s->num_pages = qemu_get_be32(f); 352 s->actual = qemu_get_be32(f); 353 return 0; 354 } 355 356 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 357 { 358 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 359 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 360 int ret; 361 362 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 363 sizeof(struct virtio_balloon_config)); 364 365 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 366 virtio_balloon_stat, s); 367 368 if (ret < 0) { 369 error_setg(errp, "Adding balloon handler failed"); 370 virtio_cleanup(vdev); 371 return; 372 } 373 374 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 375 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 376 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 377 378 reset_stats(s); 379 380 register_savevm(dev, "virtio-balloon", -1, 1, 381 virtio_balloon_save, virtio_balloon_load, s); 382 383 object_property_add(OBJECT(dev), "guest-stats", "guest statistics", 384 balloon_stats_get_all, NULL, NULL, s, NULL); 385 386 object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int", 387 balloon_stats_get_poll_interval, 388 balloon_stats_set_poll_interval, 389 NULL, s, NULL); 390 } 391 392 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp) 393 { 394 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 395 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 396 397 balloon_stats_destroy_timer(s); 398 qemu_remove_balloon_handler(s); 399 unregister_savevm(dev, "virtio-balloon", s); 400 virtio_cleanup(vdev); 401 } 402 403 static Property virtio_balloon_properties[] = { 404 DEFINE_PROP_END_OF_LIST(), 405 }; 406 407 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 408 { 409 DeviceClass *dc = DEVICE_CLASS(klass); 410 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 411 412 dc->props = virtio_balloon_properties; 413 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 414 vdc->realize = virtio_balloon_device_realize; 415 vdc->unrealize = virtio_balloon_device_unrealize; 416 vdc->get_config = virtio_balloon_get_config; 417 vdc->set_config = virtio_balloon_set_config; 418 vdc->get_features = virtio_balloon_get_features; 419 } 420 421 static const TypeInfo virtio_balloon_info = { 422 .name = TYPE_VIRTIO_BALLOON, 423 .parent = TYPE_VIRTIO_DEVICE, 424 .instance_size = sizeof(VirtIOBalloon), 425 .class_init = virtio_balloon_class_init, 426 }; 427 428 static void virtio_register_types(void) 429 { 430 type_register_static(&virtio_balloon_info); 431 } 432 433 type_init(virtio_register_types) 434