hw/virtio/virtio-mem.c

   1 /*
   2  * Virtio MEM device
   3  *
   4  * Copyright (C) 2020 Red Hat, Inc.
   5  *
   6  * Authors:
   7  *  David Hildenbrand <david@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qemu-common.h"
  15 #include "qemu/iov.h"
  16 #include "qemu/cutils.h"
  17 #include "qemu/error-report.h"
  18 #include "qemu/units.h"
  19 #include "sysemu/numa.h"
  20 #include "sysemu/sysemu.h"
  21 #include "sysemu/reset.h"
  22 #include "hw/virtio/virtio.h"
  23 #include "hw/virtio/virtio-bus.h"
  24 #include "hw/virtio/virtio-access.h"
  25 #include "hw/virtio/virtio-mem.h"
  26 #include "qapi/error.h"
  27 #include "qapi/visitor.h"
  28 #include "exec/ram_addr.h"
  29 #include "migration/misc.h"
  30 #include "hw/boards.h"
  31 #include "hw/qdev-properties.h"
  32 #include "config-devices.h"
  33 #include "trace.h"
  34
  35 /*
  36  * Use QEMU_VMALLOC_ALIGN, so no THP will have to be split when unplugging
  37  * memory (e.g., 2MB on x86_64).
  38  */
  39 #define VIRTIO_MEM_MIN_BLOCK_SIZE QEMU_VMALLOC_ALIGN
  40 /*
  41  * Size the usable region bigger than the requested size if possible. Esp.
  42  * Linux guests will only add (aligned) memory blocks in case they fully
  43  * fit into the usable region, but plug+online only a subset of the pages.
  44  * The memory block size corresponds mostly to the section size.
  45  *
  46  * This allows e.g., to add 20MB with a section size of 128MB on x86_64, and
  47  * a section size of 1GB on arm64 (as long as the start address is properly
  48  * aligned, similar to ordinary DIMMs).
  49  *
  50  * We can change this at any time and maybe even make it configurable if
  51  * necessary (as the section size can change). But it's more likely that the
  52  * section size will rather get smaller and not bigger over time.
  53  */
  54 #if defined(TARGET_X86_64) || defined(TARGET_I386)
  55 #define VIRTIO_MEM_USABLE_EXTENT (2 * (128 * MiB))
  56 #else
  57 #error VIRTIO_MEM_USABLE_EXTENT not defined
  58 #endif
  59
  60 static bool virtio_mem_is_busy(void)
  61 {
  62     /*
  63      * Postcopy cannot handle concurrent discards and we don't want to migrate
  64      * pages on-demand with stale content when plugging new blocks.
  65      *
  66      * For precopy, we don't want unplugged blocks in our migration stream, and
  67      * when plugging new blocks, the page content might differ between source
  68      * and destination (observable by the guest when not initializing pages
  69      * after plugging them) until we're running on the destination (as we didn't
  70      * migrate these blocks when they were unplugged).
  71      */
  72     return migration_in_incoming_postcopy() || !migration_is_idle();
  73 }
  74
  75 static bool virtio_mem_test_bitmap(VirtIOMEM *vmem, uint64_t start_gpa,
  76                                    uint64_t size, bool plugged)
  77 {
  78     const unsigned long first_bit = (start_gpa - vmem->addr) / vmem->block_size;
  79     const unsigned long last_bit = first_bit + (size / vmem->block_size) - 1;
  80     unsigned long found_bit;
  81
  82     /* We fake a shorter bitmap to avoid searching too far. */
  83     if (plugged) {
  84         found_bit = find_next_zero_bit(vmem->bitmap, last_bit + 1, first_bit);
  85     } else {
  86         found_bit = find_next_bit(vmem->bitmap, last_bit + 1, first_bit);
  87     }
  88     return found_bit > last_bit;
  89 }
  90
  91 static void virtio_mem_set_bitmap(VirtIOMEM *vmem, uint64_t start_gpa,
  92                                   uint64_t size, bool plugged)
  93 {
  94     const unsigned long bit = (start_gpa - vmem->addr) / vmem->block_size;
  95     const unsigned long nbits = size / vmem->block_size;
  96
  97     if (plugged) {
  98         bitmap_set(vmem->bitmap, bit, nbits);
  99     } else {
 100         bitmap_clear(vmem->bitmap, bit, nbits);
 101     }
 102 }
 103
 104 static void virtio_mem_send_response(VirtIOMEM *vmem, VirtQueueElement *elem,
 105                                      struct virtio_mem_resp *resp)
 106 {
 107     VirtIODevice *vdev = VIRTIO_DEVICE(vmem);
 108     VirtQueue *vq = vmem->vq;
 109
 110     trace_virtio_mem_send_response(le16_to_cpu(resp->type));
 111     iov_from_buf(elem->in_sg, elem->in_num, 0, resp, sizeof(*resp));
 112
 113     virtqueue_push(vq, elem, sizeof(*resp));
 114     virtio_notify(vdev, vq);
 115 }
 116
 117 static void virtio_mem_send_response_simple(VirtIOMEM *vmem,
 118                                             VirtQueueElement *elem,
 119                                             uint16_t type)
 120 {
 121     struct virtio_mem_resp resp = {
 122         .type = cpu_to_le16(type),
 123     };
 124
 125     virtio_mem_send_response(vmem, elem, &resp);
 126 }
 127
 128 static bool virtio_mem_valid_range(VirtIOMEM *vmem, uint64_t gpa, uint64_t size)
 129 {
 130     if (!QEMU_IS_ALIGNED(gpa, vmem->block_size)) {
 131         return false;
 132     }
 133     if (gpa + size < gpa || !size) {
 134         return false;
 135     }
 136     if (gpa < vmem->addr || gpa >= vmem->addr + vmem->usable_region_size) {
 137         return false;
 138     }
 139     if (gpa + size > vmem->addr + vmem->usable_region_size) {
 140         return false;
 141     }
 142     return true;
 143 }
 144
 145 static int virtio_mem_set_block_state(VirtIOMEM *vmem, uint64_t start_gpa,
 146                                       uint64_t size, bool plug)
 147 {
 148     const uint64_t offset = start_gpa - vmem->addr;
 149     int ret;
 150
 151     if (virtio_mem_is_busy()) {
 152         return -EBUSY;
 153     }
 154
 155     if (!plug) {
 156         ret = ram_block_discard_range(vmem->memdev->mr.ram_block, offset, size);
 157         if (ret) {
 158             error_report("Unexpected error discarding RAM: %s",
 159                          strerror(-ret));
 160             return -EBUSY;
 161         }
 162     }
 163     virtio_mem_set_bitmap(vmem, start_gpa, size, plug);
 164     return 0;
 165 }
 166
 167 static int virtio_mem_state_change_request(VirtIOMEM *vmem, uint64_t gpa,
 168                                            uint16_t nb_blocks, bool plug)
 169 {
 170     const uint64_t size = nb_blocks * vmem->block_size;
 171     int ret;
 172
 173     if (!virtio_mem_valid_range(vmem, gpa, size)) {
 174         return VIRTIO_MEM_RESP_ERROR;
 175     }
 176
 177     if (plug && (vmem->size + size > vmem->requested_size)) {
 178         return VIRTIO_MEM_RESP_NACK;
 179     }
 180
 181     /* test if really all blocks are in the opposite state */
 182     if (!virtio_mem_test_bitmap(vmem, gpa, size, !plug)) {
 183         return VIRTIO_MEM_RESP_ERROR;
 184     }
 185
 186     ret = virtio_mem_set_block_state(vmem, gpa, size, plug);
 187     if (ret) {
 188         return VIRTIO_MEM_RESP_BUSY;
 189     }
 190     if (plug) {
 191         vmem->size += size;
 192     } else {
 193         vmem->size -= size;
 194     }
 195     notifier_list_notify(&vmem->size_change_notifiers, &vmem->size);
 196     return VIRTIO_MEM_RESP_ACK;
 197 }
 198
 199 static void virtio_mem_plug_request(VirtIOMEM *vmem, VirtQueueElement *elem,
 200                                     struct virtio_mem_req *req)
 201 {
 202     const uint64_t gpa = le64_to_cpu(req->u.plug.addr);
 203     const uint16_t nb_blocks = le16_to_cpu(req->u.plug.nb_blocks);
 204     uint16_t type;
 205
 206     trace_virtio_mem_plug_request(gpa, nb_blocks);
 207     type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, true);
 208     virtio_mem_send_response_simple(vmem, elem, type);
 209 }
 210
 211 static void virtio_mem_unplug_request(VirtIOMEM *vmem, VirtQueueElement *elem,
 212                                       struct virtio_mem_req *req)
 213 {
 214     const uint64_t gpa = le64_to_cpu(req->u.unplug.addr);
 215     const uint16_t nb_blocks = le16_to_cpu(req->u.unplug.nb_blocks);
 216     uint16_t type;
 217
 218     trace_virtio_mem_unplug_request(gpa, nb_blocks);
 219     type = virtio_mem_state_change_request(vmem, gpa, nb_blocks, false);
 220     virtio_mem_send_response_simple(vmem, elem, type);
 221 }
 222
 223 static void virtio_mem_resize_usable_region(VirtIOMEM *vmem,
 224                                             uint64_t requested_size,
 225                                             bool can_shrink)
 226 {
 227     uint64_t newsize = MIN(memory_region_size(&vmem->memdev->mr),
 228                            requested_size + VIRTIO_MEM_USABLE_EXTENT);
 229
 230     if (!requested_size) {
 231         newsize = 0;
 232     }
 233
 234     if (newsize < vmem->usable_region_size && !can_shrink) {
 235         return;
 236     }
 237
 238     trace_virtio_mem_resized_usable_region(vmem->usable_region_size, newsize);
 239     vmem->usable_region_size = newsize;
 240 }
 241
 242 static int virtio_mem_unplug_all(VirtIOMEM *vmem)
 243 {
 244     RAMBlock *rb = vmem->memdev->mr.ram_block;
 245     int ret;
 246
 247     if (virtio_mem_is_busy()) {
 248         return -EBUSY;
 249     }
 250
 251     ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb));
 252     if (ret) {
 253         error_report("Unexpected error discarding RAM: %s", strerror(-ret));
 254         return -EBUSY;
 255     }
 256     bitmap_clear(vmem->bitmap, 0, vmem->bitmap_size);
 257     if (vmem->size) {
 258         vmem->size = 0;
 259         notifier_list_notify(&vmem->size_change_notifiers, &vmem->size);
 260     }
 261     trace_virtio_mem_unplugged_all();
 262     virtio_mem_resize_usable_region(vmem, vmem->requested_size, true);
 263     return 0;
 264 }
 265
 266 static void virtio_mem_unplug_all_request(VirtIOMEM *vmem,
 267                                           VirtQueueElement *elem)
 268 {
 269     trace_virtio_mem_unplug_all_request();
 270     if (virtio_mem_unplug_all(vmem)) {
 271         virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_BUSY);
 272     } else {
 273         virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ACK);
 274     }
 275 }
 276
 277 static void virtio_mem_state_request(VirtIOMEM *vmem, VirtQueueElement *elem,
 278                                      struct virtio_mem_req *req)
 279 {
 280     const uint16_t nb_blocks = le16_to_cpu(req->u.state.nb_blocks);
 281     const uint64_t gpa = le64_to_cpu(req->u.state.addr);
 282     const uint64_t size = nb_blocks * vmem->block_size;
 283     struct virtio_mem_resp resp = {
 284         .type = cpu_to_le16(VIRTIO_MEM_RESP_ACK),
 285     };
 286
 287     trace_virtio_mem_state_request(gpa, nb_blocks);
 288     if (!virtio_mem_valid_range(vmem, gpa, size)) {
 289         virtio_mem_send_response_simple(vmem, elem, VIRTIO_MEM_RESP_ERROR);
 290         return;
 291     }
 292
 293     if (virtio_mem_test_bitmap(vmem, gpa, size, true)) {
 294         resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_PLUGGED);
 295     } else if (virtio_mem_test_bitmap(vmem, gpa, size, false)) {
 296         resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_UNPLUGGED);
 297     } else {
 298         resp.u.state.state = cpu_to_le16(VIRTIO_MEM_STATE_MIXED);
 299     }
 300     trace_virtio_mem_state_response(le16_to_cpu(resp.u.state.state));
 301     virtio_mem_send_response(vmem, elem, &resp);
 302 }
 303
 304 static void virtio_mem_handle_request(VirtIODevice *vdev, VirtQueue *vq)
 305 {
 306     const int len = sizeof(struct virtio_mem_req);
 307     VirtIOMEM *vmem = VIRTIO_MEM(vdev);
 308     VirtQueueElement *elem;
 309     struct virtio_mem_req req;
 310     uint16_t type;
 311
 312     while (true) {
 313         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 314         if (!elem) {
 315             return;
 316         }
 317
 318         if (iov_to_buf(elem->out_sg, elem->out_num, 0, &req, len) < len) {
 319             virtio_error(vdev, "virtio-mem protocol violation: invalid request"
 320                          " size: %d", len);
 321             g_free(elem);
 322             return;
 323         }
 324
 325         if (iov_size(elem->in_sg, elem->in_num) <
 326             sizeof(struct virtio_mem_resp)) {
 327             virtio_error(vdev, "virtio-mem protocol violation: not enough space"
 328                          " for response: %zu",
 329                          iov_size(elem->in_sg, elem->in_num));
 330             g_free(elem);
 331             return;
 332         }
 333
 334         type = le16_to_cpu(req.type);
 335         switch (type) {
 336         case VIRTIO_MEM_REQ_PLUG:
 337             virtio_mem_plug_request(vmem, elem, &req);
 338             break;
 339         case VIRTIO_MEM_REQ_UNPLUG:
 340             virtio_mem_unplug_request(vmem, elem, &req);
 341             break;
 342         case VIRTIO_MEM_REQ_UNPLUG_ALL:
 343             virtio_mem_unplug_all_request(vmem, elem);
 344             break;
 345         case VIRTIO_MEM_REQ_STATE:
 346             virtio_mem_state_request(vmem, elem, &req);
 347             break;
 348         default:
 349             virtio_error(vdev, "virtio-mem protocol violation: unknown request"
 350                          " type: %d", type);
 351             g_free(elem);
 352             return;
 353         }
 354
 355         g_free(elem);
 356     }
 357 }
 358
 359 static void virtio_mem_get_config(VirtIODevice *vdev, uint8_t *config_data)
 360 {
 361     VirtIOMEM *vmem = VIRTIO_MEM(vdev);
 362     struct virtio_mem_config *config = (void *) config_data;
 363
 364     config->block_size = cpu_to_le64(vmem->block_size);
 365     config->node_id = cpu_to_le16(vmem->node);
 366     config->requested_size = cpu_to_le64(vmem->requested_size);
 367     config->plugged_size = cpu_to_le64(vmem->size);
 368     config->addr = cpu_to_le64(vmem->addr);
 369     config->region_size = cpu_to_le64(memory_region_size(&vmem->memdev->mr));
 370     config->usable_region_size = cpu_to_le64(vmem->usable_region_size);
 371 }
 372
 373 static uint64_t virtio_mem_get_features(VirtIODevice *vdev, uint64_t features,
 374                                         Error **errp)
 375 {
 376     MachineState *ms = MACHINE(qdev_get_machine());
 377
 378     if (ms->numa_state) {
 379 #if defined(CONFIG_ACPI)
 380         virtio_add_feature(&features, VIRTIO_MEM_F_ACPI_PXM);
 381 #endif
 382     }
 383     return features;
 384 }
 385
 386 static void virtio_mem_system_reset(void *opaque)
 387 {
 388     VirtIOMEM *vmem = VIRTIO_MEM(opaque);
 389
 390     /*
 391      * During usual resets, we will unplug all memory and shrink the usable
 392      * region size. This is, however, not possible in all scenarios. Then,
 393      * the guest has to deal with this manually (VIRTIO_MEM_REQ_UNPLUG_ALL).
 394      */
 395     virtio_mem_unplug_all(vmem);
 396 }
 397
 398 static void virtio_mem_device_realize(DeviceState *dev, Error **errp)
 399 {
 400     MachineState *ms = MACHINE(qdev_get_machine());
 401     int nb_numa_nodes = ms->numa_state ? ms->numa_state->num_nodes : 0;
 402     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 403     VirtIOMEM *vmem = VIRTIO_MEM(dev);
 404     uint64_t page_size;
 405     RAMBlock *rb;
 406     int ret;
 407
 408     if (!vmem->memdev) {
 409         error_setg(errp, "'%s' property is not set", VIRTIO_MEM_MEMDEV_PROP);
 410         return;
 411     } else if (host_memory_backend_is_mapped(vmem->memdev)) {
 412         char *path = object_get_canonical_path_component(OBJECT(vmem->memdev));
 413
 414         error_setg(errp, "'%s' property specifies a busy memdev: %s",
 415                    VIRTIO_MEM_MEMDEV_PROP, path);
 416         g_free(path);
 417         return;
 418     } else if (!memory_region_is_ram(&vmem->memdev->mr) ||
 419         memory_region_is_rom(&vmem->memdev->mr) ||
 420         !vmem->memdev->mr.ram_block) {
 421         error_setg(errp, "'%s' property specifies an unsupported memdev",
 422                    VIRTIO_MEM_MEMDEV_PROP);
 423         return;
 424     }
 425
 426     if ((nb_numa_nodes && vmem->node >= nb_numa_nodes) ||
 427         (!nb_numa_nodes && vmem->node)) {
 428         error_setg(errp, "'%s' property has value '%" PRIu32 "', which exceeds"
 429                    "the number of numa nodes: %d", VIRTIO_MEM_NODE_PROP,
 430                    vmem->node, nb_numa_nodes ? nb_numa_nodes : 1);
 431         return;
 432     }
 433
 434     if (enable_mlock) {
 435         error_setg(errp, "Incompatible with mlock");
 436         return;
 437     }
 438
 439     rb = vmem->memdev->mr.ram_block;
 440     page_size = qemu_ram_pagesize(rb);
 441
 442     if (vmem->block_size < page_size) {
 443         error_setg(errp, "'%s' property has to be at least the page size (0x%"
 444                    PRIx64 ")", VIRTIO_MEM_BLOCK_SIZE_PROP, page_size);
 445         return;
 446     } else if (!QEMU_IS_ALIGNED(vmem->requested_size, vmem->block_size)) {
 447         error_setg(errp, "'%s' property has to be multiples of '%s' (0x%" PRIx64
 448                    ")", VIRTIO_MEM_REQUESTED_SIZE_PROP,
 449                    VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size);
 450         return;
 451     } else if (!QEMU_IS_ALIGNED(memory_region_size(&vmem->memdev->mr),
 452                                 vmem->block_size)) {
 453         error_setg(errp, "'%s' property memdev size has to be multiples of"
 454                    "'%s' (0x%" PRIx64 ")", VIRTIO_MEM_MEMDEV_PROP,
 455                    VIRTIO_MEM_BLOCK_SIZE_PROP, vmem->block_size);
 456         return;
 457     }
 458
 459     if (ram_block_discard_require(true)) {
 460         error_setg(errp, "Discarding RAM is disabled");
 461         return;
 462     }
 463
 464     ret = ram_block_discard_range(rb, 0, qemu_ram_get_used_length(rb));
 465     if (ret) {
 466         error_setg_errno(errp, -ret, "Unexpected error discarding RAM");
 467         ram_block_discard_require(false);
 468         return;
 469     }
 470
 471     virtio_mem_resize_usable_region(vmem, vmem->requested_size, true);
 472
 473     vmem->bitmap_size = memory_region_size(&vmem->memdev->mr) /
 474                         vmem->block_size;
 475     vmem->bitmap = bitmap_new(vmem->bitmap_size);
 476
 477     virtio_init(vdev, TYPE_VIRTIO_MEM, VIRTIO_ID_MEM,
 478                 sizeof(struct virtio_mem_config));
 479     vmem->vq = virtio_add_queue(vdev, 128, virtio_mem_handle_request);
 480
 481     host_memory_backend_set_mapped(vmem->memdev, true);
 482     vmstate_register_ram(&vmem->memdev->mr, DEVICE(vmem));
 483     qemu_register_reset(virtio_mem_system_reset, vmem);
 484     precopy_add_notifier(&vmem->precopy_notifier);
 485 }
 486
 487 static void virtio_mem_device_unrealize(DeviceState *dev)
 488 {
 489     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 490     VirtIOMEM *vmem = VIRTIO_MEM(dev);
 491
 492     precopy_remove_notifier(&vmem->precopy_notifier);
 493     qemu_unregister_reset(virtio_mem_system_reset, vmem);
 494     vmstate_unregister_ram(&vmem->memdev->mr, DEVICE(vmem));
 495     host_memory_backend_set_mapped(vmem->memdev, false);
 496     virtio_del_queue(vdev, 0);
 497     virtio_cleanup(vdev);
 498     g_free(vmem->bitmap);
 499     ram_block_discard_require(false);
 500 }
 501
 502 static int virtio_mem_restore_unplugged(VirtIOMEM *vmem)
 503 {
 504     RAMBlock *rb = vmem->memdev->mr.ram_block;
 505     unsigned long first_zero_bit, last_zero_bit;
 506     uint64_t offset, length;
 507     int ret;
 508
 509     /* Find consecutive unplugged blocks and discard the consecutive range. */
 510     first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size);
 511     while (first_zero_bit < vmem->bitmap_size) {
 512         offset = first_zero_bit * vmem->block_size;
 513         last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
 514                                       first_zero_bit + 1) - 1;
 515         length = (last_zero_bit - first_zero_bit + 1) * vmem->block_size;
 516
 517         ret = ram_block_discard_range(rb, offset, length);
 518         if (ret) {
 519             error_report("Unexpected error discarding RAM: %s",
 520                          strerror(-ret));
 521             return -EINVAL;
 522         }
 523         first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
 524                                             last_zero_bit + 2);
 525     }
 526     return 0;
 527 }
 528
 529 static int virtio_mem_post_load(void *opaque, int version_id)
 530 {
 531     if (migration_in_incoming_postcopy()) {
 532         return 0;
 533     }
 534
 535     return virtio_mem_restore_unplugged(VIRTIO_MEM(opaque));
 536 }
 537
 538 typedef struct VirtIOMEMMigSanityChecks {
 539     VirtIOMEM *parent;
 540     uint64_t addr;
 541     uint64_t region_size;
 542     uint64_t block_size;
 543     uint32_t node;
 544 } VirtIOMEMMigSanityChecks;
 545
 546 static int virtio_mem_mig_sanity_checks_pre_save(void *opaque)
 547 {
 548     VirtIOMEMMigSanityChecks *tmp = opaque;
 549     VirtIOMEM *vmem = tmp->parent;
 550
 551     tmp->addr = vmem->addr;
 552     tmp->region_size = memory_region_size(&vmem->memdev->mr);
 553     tmp->block_size = vmem->block_size;
 554     tmp->node = vmem->node;
 555     return 0;
 556 }
 557
 558 static int virtio_mem_mig_sanity_checks_post_load(void *opaque, int version_id)
 559 {
 560     VirtIOMEMMigSanityChecks *tmp = opaque;
 561     VirtIOMEM *vmem = tmp->parent;
 562     const uint64_t new_region_size = memory_region_size(&vmem->memdev->mr);
 563
 564     if (tmp->addr != vmem->addr) {
 565         error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64,
 566                      VIRTIO_MEM_ADDR_PROP, tmp->addr, vmem->addr);
 567         return -EINVAL;
 568     }
 569     /*
 570      * Note: Preparation for resizeable memory regions. The maximum size
 571      * of the memory region must not change during migration.
 572      */
 573     if (tmp->region_size != new_region_size) {
 574         error_report("Property '%s' size changed from 0x%" PRIx64 " to 0x%"
 575                      PRIx64, VIRTIO_MEM_MEMDEV_PROP, tmp->region_size,
 576                      new_region_size);
 577         return -EINVAL;
 578     }
 579     if (tmp->block_size != vmem->block_size) {
 580         error_report("Property '%s' changed from 0x%" PRIx64 " to 0x%" PRIx64,
 581                      VIRTIO_MEM_BLOCK_SIZE_PROP, tmp->block_size,
 582                      vmem->block_size);
 583         return -EINVAL;
 584     }
 585     if (tmp->node != vmem->node) {
 586         error_report("Property '%s' changed from %" PRIu32 " to %" PRIu32,
 587                      VIRTIO_MEM_NODE_PROP, tmp->node, vmem->node);
 588         return -EINVAL;
 589     }
 590     return 0;
 591 }
 592
 593 static const VMStateDescription vmstate_virtio_mem_sanity_checks = {
 594     .name = "virtio-mem-device/sanity-checks",
 595     .pre_save = virtio_mem_mig_sanity_checks_pre_save,
 596     .post_load = virtio_mem_mig_sanity_checks_post_load,
 597     .fields = (VMStateField[]) {
 598         VMSTATE_UINT64(addr, VirtIOMEMMigSanityChecks),
 599         VMSTATE_UINT64(region_size, VirtIOMEMMigSanityChecks),
 600         VMSTATE_UINT64(block_size, VirtIOMEMMigSanityChecks),
 601         VMSTATE_UINT32(node, VirtIOMEMMigSanityChecks),
 602         VMSTATE_END_OF_LIST(),
 603     },
 604 };
 605
 606 static const VMStateDescription vmstate_virtio_mem_device = {
 607     .name = "virtio-mem-device",
 608     .minimum_version_id = 1,
 609     .version_id = 1,
 610     .post_load = virtio_mem_post_load,
 611     .fields = (VMStateField[]) {
 612         VMSTATE_WITH_TMP(VirtIOMEM, VirtIOMEMMigSanityChecks,
 613                          vmstate_virtio_mem_sanity_checks),
 614         VMSTATE_UINT64(usable_region_size, VirtIOMEM),
 615         VMSTATE_UINT64(size, VirtIOMEM),
 616         VMSTATE_UINT64(requested_size, VirtIOMEM),
 617         VMSTATE_BITMAP(bitmap, VirtIOMEM, 0, bitmap_size),
 618         VMSTATE_END_OF_LIST()
 619     },
 620 };
 621
 622 static const VMStateDescription vmstate_virtio_mem = {
 623     .name = "virtio-mem",
 624     .minimum_version_id = 1,
 625     .version_id = 1,
 626     .fields = (VMStateField[]) {
 627         VMSTATE_VIRTIO_DEVICE,
 628         VMSTATE_END_OF_LIST()
 629     },
 630 };
 631
 632 static void virtio_mem_fill_device_info(const VirtIOMEM *vmem,
 633                                         VirtioMEMDeviceInfo *vi)
 634 {
 635     vi->memaddr = vmem->addr;
 636     vi->node = vmem->node;
 637     vi->requested_size = vmem->requested_size;
 638     vi->size = vmem->size;
 639     vi->max_size = memory_region_size(&vmem->memdev->mr);
 640     vi->block_size = vmem->block_size;
 641     vi->memdev = object_get_canonical_path(OBJECT(vmem->memdev));
 642 }
 643
 644 static MemoryRegion *virtio_mem_get_memory_region(VirtIOMEM *vmem, Error **errp)
 645 {
 646     if (!vmem->memdev) {
 647         error_setg(errp, "'%s' property must be set", VIRTIO_MEM_MEMDEV_PROP);
 648         return NULL;
 649     }
 650
 651     return &vmem->memdev->mr;
 652 }
 653
 654 static void virtio_mem_add_size_change_notifier(VirtIOMEM *vmem,
 655                                                 Notifier *notifier)
 656 {
 657     notifier_list_add(&vmem->size_change_notifiers, notifier);
 658 }
 659
 660 static void virtio_mem_remove_size_change_notifier(VirtIOMEM *vmem,
 661                                                    Notifier *notifier)
 662 {
 663     notifier_remove(notifier);
 664 }
 665
 666 static void virtio_mem_get_size(Object *obj, Visitor *v, const char *name,
 667                                 void *opaque, Error **errp)
 668 {
 669     const VirtIOMEM *vmem = VIRTIO_MEM(obj);
 670     uint64_t value = vmem->size;
 671
 672     visit_type_size(v, name, &value, errp);
 673 }
 674
 675 static void virtio_mem_get_requested_size(Object *obj, Visitor *v,
 676                                           const char *name, void *opaque,
 677                                           Error **errp)
 678 {
 679     const VirtIOMEM *vmem = VIRTIO_MEM(obj);
 680     uint64_t value = vmem->requested_size;
 681
 682     visit_type_size(v, name, &value, errp);
 683 }
 684
 685 static void virtio_mem_set_requested_size(Object *obj, Visitor *v,
 686                                           const char *name, void *opaque,
 687                                           Error **errp)
 688 {
 689     VirtIOMEM *vmem = VIRTIO_MEM(obj);
 690     Error *err = NULL;
 691     uint64_t value;
 692
 693     visit_type_size(v, name, &value, &err);
 694     if (err) {
 695         error_propagate(errp, err);
 696         return;
 697     }
 698
 699     /*
 700      * The block size and memory backend are not fixed until the device was
 701      * realized. realize() will verify these properties then.
 702      */
 703     if (DEVICE(obj)->realized) {
 704         if (!QEMU_IS_ALIGNED(value, vmem->block_size)) {
 705             error_setg(errp, "'%s' has to be multiples of '%s' (0x%" PRIx64
 706                        ")", name, VIRTIO_MEM_BLOCK_SIZE_PROP,
 707                        vmem->block_size);
 708             return;
 709         } else if (value > memory_region_size(&vmem->memdev->mr)) {
 710             error_setg(errp, "'%s' cannot exceed the memory backend size"
 711                        "(0x%" PRIx64 ")", name,
 712                        memory_region_size(&vmem->memdev->mr));
 713             return;
 714         }
 715
 716         if (value != vmem->requested_size) {
 717             virtio_mem_resize_usable_region(vmem, value, false);
 718             vmem->requested_size = value;
 719         }
 720         /*
 721          * Trigger a config update so the guest gets notified. We trigger
 722          * even if the size didn't change (especially helpful for debugging).
 723          */
 724         virtio_notify_config(VIRTIO_DEVICE(vmem));
 725     } else {
 726         vmem->requested_size = value;
 727     }
 728 }
 729
 730 static void virtio_mem_get_block_size(Object *obj, Visitor *v, const char *name,
 731                                       void *opaque, Error **errp)
 732 {
 733     const VirtIOMEM *vmem = VIRTIO_MEM(obj);
 734     uint64_t value = vmem->block_size;
 735
 736     visit_type_size(v, name, &value, errp);
 737 }
 738
 739 static void virtio_mem_set_block_size(Object *obj, Visitor *v, const char *name,
 740                                       void *opaque, Error **errp)
 741 {
 742     VirtIOMEM *vmem = VIRTIO_MEM(obj);
 743     Error *err = NULL;
 744     uint64_t value;
 745
 746     if (DEVICE(obj)->realized) {
 747         error_setg(errp, "'%s' cannot be changed", name);
 748         return;
 749     }
 750
 751     visit_type_size(v, name, &value, &err);
 752     if (err) {
 753         error_propagate(errp, err);
 754         return;
 755     }
 756
 757     if (value < VIRTIO_MEM_MIN_BLOCK_SIZE) {
 758         error_setg(errp, "'%s' property has to be at least 0x%" PRIx32, name,
 759                    VIRTIO_MEM_MIN_BLOCK_SIZE);
 760         return;
 761     } else if (!is_power_of_2(value)) {
 762         error_setg(errp, "'%s' property has to be a power of two", name);
 763         return;
 764     }
 765     vmem->block_size = value;
 766 }
 767
 768 static void virtio_mem_precopy_exclude_unplugged(VirtIOMEM *vmem)
 769 {
 770     void * const host = qemu_ram_get_host_addr(vmem->memdev->mr.ram_block);
 771     unsigned long first_zero_bit, last_zero_bit;
 772     uint64_t offset, length;
 773
 774     /*
 775      * Find consecutive unplugged blocks and exclude them from migration.
 776      *
 777      * Note: Blocks cannot get (un)plugged during precopy, no locking needed.
 778      */
 779     first_zero_bit = find_first_zero_bit(vmem->bitmap, vmem->bitmap_size);
 780     while (first_zero_bit < vmem->bitmap_size) {
 781         offset = first_zero_bit * vmem->block_size;
 782         last_zero_bit = find_next_bit(vmem->bitmap, vmem->bitmap_size,
 783                                       first_zero_bit + 1) - 1;
 784         length = (last_zero_bit - first_zero_bit + 1) * vmem->block_size;
 785
 786         qemu_guest_free_page_hint(host + offset, length);
 787         first_zero_bit = find_next_zero_bit(vmem->bitmap, vmem->bitmap_size,
 788                                             last_zero_bit + 2);
 789     }
 790 }
 791
 792 static int virtio_mem_precopy_notify(NotifierWithReturn *n, void *data)
 793 {
 794     VirtIOMEM *vmem = container_of(n, VirtIOMEM, precopy_notifier);
 795     PrecopyNotifyData *pnd = data;
 796
 797     switch (pnd->reason) {
 798     case PRECOPY_NOTIFY_SETUP:
 799         precopy_enable_free_page_optimization();
 800         break;
 801     case PRECOPY_NOTIFY_AFTER_BITMAP_SYNC:
 802         virtio_mem_precopy_exclude_unplugged(vmem);
 803         break;
 804     default:
 805         break;
 806     }
 807
 808     return 0;
 809 }
 810
 811 static void virtio_mem_instance_init(Object *obj)
 812 {
 813     VirtIOMEM *vmem = VIRTIO_MEM(obj);
 814
 815     vmem->block_size = VIRTIO_MEM_MIN_BLOCK_SIZE;
 816     notifier_list_init(&vmem->size_change_notifiers);
 817     vmem->precopy_notifier.notify = virtio_mem_precopy_notify;
 818
 819     object_property_add(obj, VIRTIO_MEM_SIZE_PROP, "size", virtio_mem_get_size,
 820                         NULL, NULL, NULL);
 821     object_property_add(obj, VIRTIO_MEM_REQUESTED_SIZE_PROP, "size",
 822                         virtio_mem_get_requested_size,
 823                         virtio_mem_set_requested_size, NULL, NULL);
 824     object_property_add(obj, VIRTIO_MEM_BLOCK_SIZE_PROP, "size",
 825                         virtio_mem_get_block_size, virtio_mem_set_block_size,
 826                         NULL, NULL);
 827 }
 828
 829 static Property virtio_mem_properties[] = {
 830     DEFINE_PROP_UINT64(VIRTIO_MEM_ADDR_PROP, VirtIOMEM, addr, 0),
 831     DEFINE_PROP_UINT32(VIRTIO_MEM_NODE_PROP, VirtIOMEM, node, 0),
 832     DEFINE_PROP_LINK(VIRTIO_MEM_MEMDEV_PROP, VirtIOMEM, memdev,
 833                      TYPE_MEMORY_BACKEND, HostMemoryBackend *),
 834     DEFINE_PROP_END_OF_LIST(),
 835 };
 836
 837 static void virtio_mem_class_init(ObjectClass *klass, void *data)
 838 {
 839     DeviceClass *dc = DEVICE_CLASS(klass);
 840     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 841     VirtIOMEMClass *vmc = VIRTIO_MEM_CLASS(klass);
 842
 843     device_class_set_props(dc, virtio_mem_properties);
 844     dc->vmsd = &vmstate_virtio_mem;
 845
 846     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 847     vdc->realize = virtio_mem_device_realize;
 848     vdc->unrealize = virtio_mem_device_unrealize;
 849     vdc->get_config = virtio_mem_get_config;
 850     vdc->get_features = virtio_mem_get_features;
 851     vdc->vmsd = &vmstate_virtio_mem_device;
 852
 853     vmc->fill_device_info = virtio_mem_fill_device_info;
 854     vmc->get_memory_region = virtio_mem_get_memory_region;
 855     vmc->add_size_change_notifier = virtio_mem_add_size_change_notifier;
 856     vmc->remove_size_change_notifier = virtio_mem_remove_size_change_notifier;
 857 }
 858
 859 static const TypeInfo virtio_mem_info = {
 860     .name = TYPE_VIRTIO_MEM,
 861     .parent = TYPE_VIRTIO_DEVICE,
 862     .instance_size = sizeof(VirtIOMEM),
 863     .instance_init = virtio_mem_instance_init,
 864     .class_init = virtio_mem_class_init,
 865     .class_size = sizeof(VirtIOMEMClass),
 866 };
 867
 868 static void virtio_register_types(void)
 869 {
 870     type_register_static(&virtio_mem_info);
 871 }
 872
 873 type_init(virtio_register_types)