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