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 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 Error *local_err = NULL; 146 int64_t value; 147 148 visit_type_int(v, &value, name, &local_err); 149 if (local_err) { 150 error_propagate(errp, local_err); 151 return; 152 } 153 154 if (value < 0) { 155 error_setg(errp, "timer value must be greater than zero"); 156 return; 157 } 158 159 if (value == s->stats_poll_interval) { 160 return; 161 } 162 163 if (value == 0) { 164 /* timer=0 disables the timer */ 165 balloon_stats_destroy_timer(s); 166 return; 167 } 168 169 if (balloon_stats_enabled(s)) { 170 /* timer interval change */ 171 s->stats_poll_interval = value; 172 balloon_stats_change_timer(s, value); 173 return; 174 } 175 176 /* create a new timer */ 177 g_assert(s->stats_timer == NULL); 178 s->stats_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, balloon_stats_poll_cb, s); 179 s->stats_poll_interval = value; 180 balloon_stats_change_timer(s, 0); 181 } 182 183 static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 184 { 185 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 186 VirtQueueElement elem; 187 MemoryRegionSection section; 188 189 while (virtqueue_pop(vq, &elem)) { 190 size_t offset = 0; 191 uint32_t pfn; 192 193 while (iov_to_buf(elem.out_sg, elem.out_num, offset, &pfn, 4) == 4) { 194 ram_addr_t pa; 195 ram_addr_t addr; 196 197 pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT; 198 offset += 4; 199 200 /* FIXME: remove get_system_memory(), but how? */ 201 section = memory_region_find(get_system_memory(), pa, 1); 202 if (!int128_nz(section.size) || !memory_region_is_ram(section.mr)) 203 continue; 204 205 /* Using memory_region_get_ram_ptr is bending the rules a bit, but 206 should be OK because we only want a single page. */ 207 addr = section.offset_within_region; 208 balloon_page(memory_region_get_ram_ptr(section.mr) + addr, 209 !!(vq == s->dvq)); 210 memory_region_unref(section.mr); 211 } 212 213 virtqueue_push(vq, &elem, offset); 214 virtio_notify(vdev, vq); 215 } 216 } 217 218 static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq) 219 { 220 VirtIOBalloon *s = VIRTIO_BALLOON(vdev); 221 VirtQueueElement *elem = &s->stats_vq_elem; 222 VirtIOBalloonStat stat; 223 size_t offset = 0; 224 qemu_timeval tv; 225 226 if (!virtqueue_pop(vq, elem)) { 227 goto out; 228 } 229 230 /* Initialize the stats to get rid of any stale values. This is only 231 * needed to handle the case where a guest supports fewer stats than it 232 * used to (ie. it has booted into an old kernel). 233 */ 234 reset_stats(s); 235 236 while (iov_to_buf(elem->out_sg, elem->out_num, offset, &stat, sizeof(stat)) 237 == sizeof(stat)) { 238 uint16_t tag = tswap16(stat.tag); 239 uint64_t val = tswap64(stat.val); 240 241 offset += sizeof(stat); 242 if (tag < VIRTIO_BALLOON_S_NR) 243 s->stats[tag] = val; 244 } 245 s->stats_vq_offset = offset; 246 247 if (qemu_gettimeofday(&tv) < 0) { 248 fprintf(stderr, "warning: %s: failed to get time of day\n", __func__); 249 goto out; 250 } 251 252 s->stats_last_update = tv.tv_sec; 253 254 out: 255 if (balloon_stats_enabled(s)) { 256 balloon_stats_change_timer(s, s->stats_poll_interval); 257 } 258 } 259 260 static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) 261 { 262 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 263 struct virtio_balloon_config config; 264 265 config.num_pages = cpu_to_le32(dev->num_pages); 266 config.actual = cpu_to_le32(dev->actual); 267 268 memcpy(config_data, &config, sizeof(struct virtio_balloon_config)); 269 } 270 271 static void virtio_balloon_set_config(VirtIODevice *vdev, 272 const uint8_t *config_data) 273 { 274 VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); 275 struct virtio_balloon_config config; 276 uint32_t oldactual = dev->actual; 277 memcpy(&config, config_data, sizeof(struct virtio_balloon_config)); 278 dev->actual = le32_to_cpu(config.actual); 279 if (dev->actual != oldactual) { 280 qemu_balloon_changed(ram_size - 281 ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT)); 282 } 283 } 284 285 static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f) 286 { 287 f |= (1 << VIRTIO_BALLOON_F_STATS_VQ); 288 return f; 289 } 290 291 static void virtio_balloon_stat(void *opaque, BalloonInfo *info) 292 { 293 VirtIOBalloon *dev = opaque; 294 info->actual = ram_size - ((uint64_t) dev->actual << 295 VIRTIO_BALLOON_PFN_SHIFT); 296 } 297 298 static void virtio_balloon_to_target(void *opaque, ram_addr_t target) 299 { 300 VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); 301 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 302 303 if (target > ram_size) { 304 target = ram_size; 305 } 306 if (target) { 307 dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT; 308 virtio_notify_config(vdev); 309 } 310 } 311 312 static void virtio_balloon_save(QEMUFile *f, void *opaque) 313 { 314 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 315 VirtIODevice *vdev = VIRTIO_DEVICE(s); 316 317 virtio_save(vdev, f); 318 319 qemu_put_be32(f, s->num_pages); 320 qemu_put_be32(f, s->actual); 321 } 322 323 static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id) 324 { 325 VirtIOBalloon *s = VIRTIO_BALLOON(opaque); 326 VirtIODevice *vdev = VIRTIO_DEVICE(s); 327 int ret; 328 329 if (version_id != 1) 330 return -EINVAL; 331 332 ret = virtio_load(vdev, f); 333 if (ret) { 334 return ret; 335 } 336 337 s->num_pages = qemu_get_be32(f); 338 s->actual = qemu_get_be32(f); 339 return 0; 340 } 341 342 static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) 343 { 344 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 345 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 346 int ret; 347 348 virtio_init(vdev, "virtio-balloon", VIRTIO_ID_BALLOON, 349 sizeof(struct virtio_balloon_config)); 350 351 ret = qemu_add_balloon_handler(virtio_balloon_to_target, 352 virtio_balloon_stat, s); 353 354 if (ret < 0) { 355 error_setg(errp, "Adding balloon handler failed"); 356 virtio_cleanup(vdev); 357 return; 358 } 359 360 s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 361 s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); 362 s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); 363 364 register_savevm(dev, "virtio-balloon", -1, 1, 365 virtio_balloon_save, virtio_balloon_load, s); 366 367 object_property_add(OBJECT(dev), "guest-stats", "guest statistics", 368 balloon_stats_get_all, NULL, NULL, s, NULL); 369 370 object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int", 371 balloon_stats_get_poll_interval, 372 balloon_stats_set_poll_interval, 373 NULL, s, NULL); 374 } 375 376 static void virtio_balloon_device_unrealize(DeviceState *dev, Error **errp) 377 { 378 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 379 VirtIOBalloon *s = VIRTIO_BALLOON(dev); 380 381 balloon_stats_destroy_timer(s); 382 qemu_remove_balloon_handler(s); 383 unregister_savevm(dev, "virtio-balloon", s); 384 virtio_cleanup(vdev); 385 } 386 387 static Property virtio_balloon_properties[] = { 388 DEFINE_PROP_END_OF_LIST(), 389 }; 390 391 static void virtio_balloon_class_init(ObjectClass *klass, void *data) 392 { 393 DeviceClass *dc = DEVICE_CLASS(klass); 394 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 395 396 dc->props = virtio_balloon_properties; 397 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 398 vdc->realize = virtio_balloon_device_realize; 399 vdc->unrealize = virtio_balloon_device_unrealize; 400 vdc->get_config = virtio_balloon_get_config; 401 vdc->set_config = virtio_balloon_set_config; 402 vdc->get_features = virtio_balloon_get_features; 403 } 404 405 static const TypeInfo virtio_balloon_info = { 406 .name = TYPE_VIRTIO_BALLOON, 407 .parent = TYPE_VIRTIO_DEVICE, 408 .instance_size = sizeof(VirtIOBalloon), 409 .class_init = virtio_balloon_class_init, 410 }; 411 412 static void virtio_register_types(void) 413 { 414 type_register_static(&virtio_balloon_info); 415 } 416 417 type_init(virtio_register_types) 418