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) 432