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 if (!s->stats_last_update) { 116 error_setg(errp, "guest hasn't updated any stats yet"); 117 return; 118 } 119 120 visit_start_struct(v, NULL, "guest-stats", name, 0, &err); 121 if (err) { 122 goto out; 123 } 124 visit_type_int(v, &s->stats_last_update, "last-update", &err); 125 if (err) { 126 goto out_end; 127 } 128 129 visit_start_struct(v, NULL, NULL, "stats", 0, &err); 130 if (err) { 131 goto out_end; 132 } 133 for (i = 0; !err && i < VIRTIO_BALLOON_S_NR; i++) { 134 visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i], 135 &err); 136 } 137 error_propagate(errp, err); 138 err = NULL; 139 visit_end_struct(v, &err); 140 141 out_end: 142 error_propagate(errp, err); 143 err = NULL; 144 visit_end_struct(v, &err); 145 out: 146 error_propagate(errp, err); 147 } 148 149 static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v, 150 void *opaque, const char *name, 151 Error **errp) 152 { 153 VirtIOBalloon *s = opaque; 154 visit_type_int(v, &s->stats_poll_interval, name, errp); 155 } 156 157 static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v, 158 void *opaque, const char *name, 159 Error **errp) 160 { 161 VirtIOBalloon *s = opaque; 162 Error *local_err = NULL; 163 int64_t value; 164 165 visit_type_int(v, &value, name, &local_err); 166 if (local_err) { 167 error_propagate(errp, local_err); 168 return; 169 } 170 171 if (value < 0) { 172 error_setg(errp, "timer value must be greater than zero"); 173 return; 174 } 175 176 if (value == s->stats_poll_interval) { 177 return; 178 } 179 180 if (value == 0) { 181 /* timer=0 disables the timer */ 182 balloon_stats_destroy_timer(s); 183 return; 184 } 185 186 if (balloon_stats_enabled(s)) { 187 /* timer interval change */ 188 s->stats_poll_interval = value; 189 balloon_stats_change_timer(s, value); 190 return; 191 } 192 193 /* create a new timer */ 194 g_assert(s->stats_timer == NULL); 195 s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); 196 s->stats_poll_interval = value; 197 balloon_stats_change_timer(s, 0); 198 } 199 200 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 201 { 202 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 203 VirtQueueElement elem; 204 MemoryRegionSection section; 205 206 while (virtqueue_pop(vq, &elem)) { 207 size_t offset = 0; 208 uint32_t pfn; 209 210 while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) { 211 ram_addr_t pa; 212 ram_addr_t addr; 213 214 pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT; 215 offset += 4; 216 217 /* FIXME: remove get_system_memory(), but how? */ 218 section = memory_region_find(get_system_memory(), pa, 1); 219 if (!int128_nz(section.size) || !memory_region_is_ram(section.mr)) 220 continue; 221 222 /* Using memory_region_get_ram_ptr is bending the rules a bit, but 223 should be OK because we only want a single page. */ 224 addr = section.offset_within_region; 225 balloon_page(memory_region_get_ram_ptr(section.mr) + addr, 226 !!(vq == s->dvq)); 227 memory_region_unref(section.mr); 228 } 229 230 virtqueue_push(vq, &elem, offset); 231 virtio_notify(vdev, vq); 232 } 233 } 234 235 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) 236 { 237 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 238 VirtQueueElement *elem = &s->stats_vq_elem; 239 VirtIOBalloonStat stat; 240 size_t offset = 0; 241 qemu_timeval tv; 242 243 if (!virtqueue_pop(vq, elem)) { 244 goto out; 245 } 246 247 /* Initialize the stats to get rid of any stale values. This is only 248 * needed to handle the case where a guest supports fewer stats than it 249 * used to (ie. it has booted into an old kernel). 250 */ 251 reset_stats(s); 252 253 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) 254 == sizeof(stat)) { 255 uint16_t tag = tswap16(stat.tag); 256 uint64_t val = tswap64(stat.val); 257 258 offset += sizeof(stat); 259 if (tag < VIRTIO_BALLOON_S_NR) 260 s->stats[tag] = val; 261 } 262 s->stats_vq_offset = offset; 263 264 if (qemu_gettimeofday(&tv) < 0) { 265 fprintf(stderr, "warning: %s: failed to get time of day\n", __func__); 266 goto out; 267 } 268 269 s->stats_last_update = tv.tv_sec; 270 271 out: 272 if (balloon_stats_enabled(s)) { 273 balloon_stats_change_timer(s, s->stats_poll_interval); 274 } 275 } 276 277 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) 278 { 279 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 280 struct virtio_balloon_config config; 281 282 config.num_pages = cpu_to_le32(dev->num_pages); 283 config.actual = cpu_to_le32(dev->actual); 284 285 memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); 286 } 287 288 static void virtio_balloon_set_config(VirtIODevice *vdev, 289 const uint8_t *config_data) 290 { 291 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 292 struct virtio_balloon_config config; 293 uint32_t oldactual = dev->actual; 294 memcpy(&config, config_data, sizeof(struct virtio_balloon_config)); 295 dev->actual = le32_to_cpu(config.actual); 296 if (dev->actual != oldactual) { 297 qemu_balloon_changed(ram_size - 298 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); 299 } 300 } 301 302 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f) 303 { 304 f |= (1 << VIRTIO_BALLOON_F_STATS_VQ); 305 return f; 306 } 307 308 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 309 { 310 VirtIOBalloon *dev = opaque; 311 info->actual = ram_size - ((uint64_t) dev->actual << 312 VIRTIO_BALLOON_PFN_SHIFT); 313 } 314 315 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 316 { 317 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 318 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 319 320 if (target > ram_size) { 321 target = ram_size; 322 } 323 if (target) { 324 dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 325 virtio_notify_config(vdev); 326 } 327 } 328 329 static void virtio_balloon_save(QEMUFile *f, void *opaque) 330 { 331 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 332 VirtIODevice *vdev = VIRTIO_DEVICE(s); 333 334 virtio_save(vdev, f); 335 336 qemu_put_be32(f, s->num_pages); 337 qemu_put_be32(f, s->actual); 338 } 339 340 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) 341 { 342 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 343 VirtIODevice *vdev = VIRTIO_DEVICE(s); 344 int ret; 345 346 if (version_id != 1) 347 return -EINVAL; 348 349 ret = virtio_load(vdev, f); 350 if (ret) { 351 return ret; 352 } 353 354 s->num_pages = qemu_get_be32(f); 355 s->actual = qemu_get_be32(f); 356 return 0; 357 } 358 359 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 360 { 361 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 362 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 363 int ret; 364 365 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 366 sizeof(struct virtio_balloon_config)); 367 368 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 369 virtio_balloon_stat, s); 370 371 if (ret < 0) { 372 error_setg(errp, "Adding balloon handler failed"); 373 virtio_cleanup(vdev); 374 return; 375 } 376 377 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 378 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 379 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 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 } 421 422 static const TypeInfo virtio_balloon_info = { 423 .name = TYPE_VIRTIO_BALLOON, 424 .parent = TYPE_VIRTIO_DEVICE, 425 .instance_size = sizeof(VirtIOBalloon), 426 .class_init = virtio_balloon_class_init, 427 }; 428 429 static void virtio_register_types(void) 430 { 431 type_register_static(&virtio_balloon_info); 432 } 433 434 type_init(virtio_register_types) 435