backends/hostmem.c

   1 /*
   2  * QEMU Host Memory Backend
   3  *
   4  * Copyright (C) 2013-2014 Red Hat Inc
   5  *
   6  * Authors:
   7  *   Igor Mammedov <imammedo@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "sysemu/hostmem.h"
  15 #include "hw/boards.h"
  16 #include "qapi/error.h"
  17 #include "qapi/qapi-builtin-visit.h"
  18 #include "qapi/visitor.h"
  19 #include "qemu/config-file.h"
  20 #include "qom/object_interfaces.h"
  21 #include "qemu/mmap-alloc.h"
  22 #include "qemu/madvise.h"
  23 #include "hw/qdev-core.h"
  24
  25 #ifdef CONFIG_NUMA
  26 #include <numaif.h>
  27 #include <numa.h>
  28 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
  29 /*
  30  * HOST_MEM_POLICY_PREFERRED may either translate to MPOL_PREFERRED or
  31  * MPOL_PREFERRED_MANY, see comments further below.
  32  */
  33 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
  34 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
  35 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
  36 #endif
  37
  38 char *
  39 host_memory_backend_get_name(HostMemoryBackend *backend)
  40 {
  41     if (!backend->use_canonical_path) {
  42         return g_strdup(object_get_canonical_path_component(OBJECT(backend)));
  43     }
  44
  45     return object_get_canonical_path(OBJECT(backend));
  46 }
  47
  48 static void
  49 host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
  50                              void *opaque, Error **errp)
  51 {
  52     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  53     uint64_t value = backend->size;
  54
  55     visit_type_size(v, name, &value, errp);
  56 }
  57
  58 static void
  59 host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
  60                              void *opaque, Error **errp)
  61 {
  62     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  63     uint64_t value;
  64
  65     if (host_memory_backend_mr_inited(backend)) {
  66         error_setg(errp, "cannot change property %s of %s ", name,
  67                    object_get_typename(obj));
  68         return;
  69     }
  70
  71     if (!visit_type_size(v, name, &value, errp)) {
  72         return;
  73     }
  74     if (!value) {
  75         error_setg(errp,
  76                    "property '%s' of %s doesn't take value '%" PRIu64 "'",
  77                    name, object_get_typename(obj), value);
  78         return;
  79     }
  80     backend->size = value;
  81 }
  82
  83 static void
  84 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
  85                                    void *opaque, Error **errp)
  86 {
  87     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  88     uint16List *host_nodes = NULL;
  89     uint16List **tail = &host_nodes;
  90     unsigned long value;
  91
  92     value = find_first_bit(backend->host_nodes, MAX_NODES);
  93     if (value == MAX_NODES) {
  94         goto ret;
  95     }
  96
  97     QAPI_LIST_APPEND(tail, value);
  98
  99     do {
 100         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
 101         if (value == MAX_NODES) {
 102             break;
 103         }
 104
 105         QAPI_LIST_APPEND(tail, value);
 106     } while (true);
 107
 108 ret:
 109     visit_type_uint16List(v, name, &host_nodes, errp);
 110     qapi_free_uint16List(host_nodes);
 111 }
 112
 113 static void
 114 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 115                                    void *opaque, Error **errp)
 116 {
 117 #ifdef CONFIG_NUMA
 118     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 119     uint16List *l, *host_nodes = NULL;
 120
 121     visit_type_uint16List(v, name, &host_nodes, errp);
 122
 123     for (l = host_nodes; l; l = l->next) {
 124         if (l->value >= MAX_NODES) {
 125             error_setg(errp, "Invalid host-nodes value: %d", l->value);
 126             goto out;
 127         }
 128     }
 129
 130     for (l = host_nodes; l; l = l->next) {
 131         bitmap_set(backend->host_nodes, l->value, 1);
 132     }
 133
 134 out:
 135     qapi_free_uint16List(host_nodes);
 136 #else
 137     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 138 #endif
 139 }
 140
 141 static int
 142 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
 143 {
 144     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 145     return backend->policy;
 146 }
 147
 148 static void
 149 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
 150 {
 151     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 152     backend->policy = policy;
 153
 154 #ifndef CONFIG_NUMA
 155     if (policy != HOST_MEM_POLICY_DEFAULT) {
 156         error_setg(errp, "NUMA policies are not supported by this QEMU");
 157     }
 158 #endif
 159 }
 160
 161 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
 162 {
 163     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 164
 165     return backend->merge;
 166 }
 167
 168 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
 169 {
 170     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 171
 172     if (!host_memory_backend_mr_inited(backend)) {
 173         backend->merge = value;
 174         return;
 175     }
 176
 177     if (value != backend->merge) {
 178         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 179         uint64_t sz = memory_region_size(&backend->mr);
 180
 181         qemu_madvise(ptr, sz,
 182                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
 183         backend->merge = value;
 184     }
 185 }
 186
 187 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
 188 {
 189     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 190
 191     return backend->dump;
 192 }
 193
 194 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
 195 {
 196     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 197
 198     if (!host_memory_backend_mr_inited(backend)) {
 199         backend->dump = value;
 200         return;
 201     }
 202
 203     if (value != backend->dump) {
 204         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 205         uint64_t sz = memory_region_size(&backend->mr);
 206
 207         qemu_madvise(ptr, sz,
 208                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
 209         backend->dump = value;
 210     }
 211 }
 212
 213 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
 214 {
 215     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 216
 217     return backend->prealloc;
 218 }
 219
 220 static void host_memory_backend_set_prealloc(Object *obj, bool value,
 221                                              Error **errp)
 222 {
 223     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 224
 225     if (!backend->reserve && value) {
 226         error_setg(errp, "'prealloc=on' and 'reserve=off' are incompatible");
 227         return;
 228     }
 229
 230     if (!host_memory_backend_mr_inited(backend)) {
 231         backend->prealloc = value;
 232         return;
 233     }
 234
 235     if (value && !backend->prealloc) {
 236         int fd = memory_region_get_fd(&backend->mr);
 237         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 238         uint64_t sz = memory_region_size(&backend->mr);
 239
 240         if (!qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads,
 241                                backend->prealloc_context, false, errp)) {
 242             return;
 243         }
 244         backend->prealloc = true;
 245     }
 246 }
 247
 248 static void host_memory_backend_get_prealloc_threads(Object *obj, Visitor *v,
 249     const char *name, void *opaque, Error **errp)
 250 {
 251     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 252     visit_type_uint32(v, name, &backend->prealloc_threads, errp);
 253 }
 254
 255 static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
 256     const char *name, void *opaque, Error **errp)
 257 {
 258     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 259     uint32_t value;
 260
 261     if (!visit_type_uint32(v, name, &value, errp)) {
 262         return;
 263     }
 264     if (value <= 0) {
 265         error_setg(errp, "property '%s' of %s doesn't take value '%d'", name,
 266                    object_get_typename(obj), value);
 267         return;
 268     }
 269     backend->prealloc_threads = value;
 270 }
 271
 272 static void host_memory_backend_init(Object *obj)
 273 {
 274     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 275     MachineState *machine = MACHINE(qdev_get_machine());
 276
 277     /* TODO: convert access to globals to compat properties */
 278     backend->merge = machine_mem_merge(machine);
 279     backend->dump = machine_dump_guest_core(machine);
 280     backend->reserve = true;
 281     backend->prealloc_threads = machine->smp.cpus;
 282 }
 283
 284 static void host_memory_backend_post_init(Object *obj)
 285 {
 286     object_apply_compat_props(obj);
 287 }
 288
 289 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
 290 {
 291     /*
 292      * NOTE: We forbid zero-length memory backend, so here zero means
 293      * "we haven't inited the backend memory region yet".
 294      */
 295     return memory_region_size(&backend->mr) != 0;
 296 }
 297
 298 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
 299 {
 300     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
 301 }
 302
 303 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
 304 {
 305     backend->is_mapped = mapped;
 306 }
 307
 308 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
 309 {
 310     return backend->is_mapped;
 311 }
 312
 313 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
 314 {
 315     size_t pagesize = qemu_ram_pagesize(memdev->mr.ram_block);
 316     g_assert(pagesize >= qemu_real_host_page_size());
 317     return pagesize;
 318 }
 319
 320 static void
 321 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
 322 {
 323     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
 324     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
 325     void *ptr;
 326     uint64_t sz;
 327     bool async = !phase_check(PHASE_LATE_BACKENDS_CREATED);
 328
 329     if (!bc->alloc) {
 330         return;
 331     }
 332     if (!bc->alloc(backend, errp)) {
 333         return;
 334     }
 335
 336     ptr = memory_region_get_ram_ptr(&backend->mr);
 337     sz = memory_region_size(&backend->mr);
 338
 339     if (backend->merge) {
 340         qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
 341     }
 342     if (!backend->dump) {
 343         qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
 344     }
 345 #ifdef CONFIG_NUMA
 346     unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
 347     /* lastbit == MAX_NODES means maxnode = 0 */
 348     unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
 349     /*
 350      * Ensure policy won't be ignored in case memory is preallocated
 351      * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
 352      * this doesn't catch hugepage case.
 353      */
 354     unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
 355     int mode = backend->policy;
 356
 357     /* check for invalid host-nodes and policies and give more verbose
 358      * error messages than mbind(). */
 359     if (maxnode && backend->policy == MPOL_DEFAULT) {
 360         error_setg(errp, "host-nodes must be empty for policy default,"
 361                    " or you should explicitly specify a policy other"
 362                    " than default");
 363         return;
 364     } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
 365         error_setg(errp, "host-nodes must be set for policy %s",
 366                    HostMemPolicy_str(backend->policy));
 367         return;
 368     }
 369
 370     /*
 371      * We can have up to MAX_NODES nodes, but we need to pass maxnode+1
 372      * as argument to mbind() due to an old Linux bug (feature?) which
 373      * cuts off the last specified node. This means backend->host_nodes
 374      * must have MAX_NODES+1 bits available.
 375      */
 376     assert(sizeof(backend->host_nodes) >=
 377            BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
 378     assert(maxnode <= MAX_NODES);
 379
 380 #ifdef HAVE_NUMA_HAS_PREFERRED_MANY
 381     if (mode == MPOL_PREFERRED && numa_has_preferred_many() > 0) {
 382         /*
 383          * Replace with MPOL_PREFERRED_MANY otherwise the mbind() below
 384          * silently picks the first node.
 385          */
 386         mode = MPOL_PREFERRED_MANY;
 387     }
 388 #endif
 389
 390     if (maxnode &&
 391         mbind(ptr, sz, mode, backend->host_nodes, maxnode + 1, flags)) {
 392         if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
 393             error_setg_errno(errp, errno,
 394                              "cannot bind memory to host NUMA nodes");
 395             return;
 396         }
 397     }
 398 #endif
 399     /*
 400      * Preallocate memory after the NUMA policy has been instantiated.
 401      * This is necessary to guarantee memory is allocated with
 402      * specified NUMA policy in place.
 403      */
 404     if (backend->prealloc && !qemu_prealloc_mem(memory_region_get_fd(&backend->mr),
 405                                                 ptr, sz,
 406                                                 backend->prealloc_threads,
 407                                                 backend->prealloc_context,
 408                                                 async, errp)) {
 409         return;
 410     }
 411 }
 412
 413 static bool
 414 host_memory_backend_can_be_deleted(UserCreatable *uc)
 415 {
 416     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
 417         return false;
 418     } else {
 419         return true;
 420     }
 421 }
 422
 423 static bool host_memory_backend_get_share(Object *o, Error **errp)
 424 {
 425     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 426
 427     return backend->share;
 428 }
 429
 430 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
 431 {
 432     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 433
 434     if (host_memory_backend_mr_inited(backend)) {
 435         error_setg(errp, "cannot change property value");
 436         return;
 437     }
 438     backend->share = value;
 439 }
 440
 441 #ifdef CONFIG_LINUX
 442 static bool host_memory_backend_get_reserve(Object *o, Error **errp)
 443 {
 444     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 445
 446     return backend->reserve;
 447 }
 448
 449 static void host_memory_backend_set_reserve(Object *o, bool value, Error **errp)
 450 {
 451     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 452
 453     if (host_memory_backend_mr_inited(backend)) {
 454         error_setg(errp, "cannot change property value");
 455         return;
 456     }
 457     if (backend->prealloc && !value) {
 458         error_setg(errp, "'prealloc=on' and 'reserve=off' are incompatible");
 459         return;
 460     }
 461     backend->reserve = value;
 462 }
 463 #endif /* CONFIG_LINUX */
 464
 465 static bool
 466 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
 467 {
 468     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 469
 470     return backend->use_canonical_path;
 471 }
 472
 473 static void
 474 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
 475                                            Error **errp)
 476 {
 477     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 478
 479     backend->use_canonical_path = value;
 480 }
 481
 482 static void
 483 host_memory_backend_class_init(ObjectClass *oc, void *data)
 484 {
 485     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 486
 487     ucc->complete = host_memory_backend_memory_complete;
 488     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
 489
 490     object_class_property_add_bool(oc, "merge",
 491         host_memory_backend_get_merge,
 492         host_memory_backend_set_merge);
 493     object_class_property_set_description(oc, "merge",
 494         "Mark memory as mergeable");
 495     object_class_property_add_bool(oc, "dump",
 496         host_memory_backend_get_dump,
 497         host_memory_backend_set_dump);
 498     object_class_property_set_description(oc, "dump",
 499         "Set to 'off' to exclude from core dump");
 500     object_class_property_add_bool(oc, "prealloc",
 501         host_memory_backend_get_prealloc,
 502         host_memory_backend_set_prealloc);
 503     object_class_property_set_description(oc, "prealloc",
 504         "Preallocate memory");
 505     object_class_property_add(oc, "prealloc-threads", "int",
 506         host_memory_backend_get_prealloc_threads,
 507         host_memory_backend_set_prealloc_threads,
 508         NULL, NULL);
 509     object_class_property_set_description(oc, "prealloc-threads",
 510         "Number of CPU threads to use for prealloc");
 511     object_class_property_add_link(oc, "prealloc-context",
 512         TYPE_THREAD_CONTEXT, offsetof(HostMemoryBackend, prealloc_context),
 513         object_property_allow_set_link, OBJ_PROP_LINK_STRONG);
 514     object_class_property_set_description(oc, "prealloc-context",
 515         "Context to use for creating CPU threads for preallocation");
 516     object_class_property_add(oc, "size", "int",
 517         host_memory_backend_get_size,
 518         host_memory_backend_set_size,
 519         NULL, NULL);
 520     object_class_property_set_description(oc, "size",
 521         "Size of the memory region (ex: 500M)");
 522     object_class_property_add(oc, "host-nodes", "int",
 523         host_memory_backend_get_host_nodes,
 524         host_memory_backend_set_host_nodes,
 525         NULL, NULL);
 526     object_class_property_set_description(oc, "host-nodes",
 527         "Binds memory to the list of NUMA host nodes");
 528     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
 529         &HostMemPolicy_lookup,
 530         host_memory_backend_get_policy,
 531         host_memory_backend_set_policy);
 532     object_class_property_set_description(oc, "policy",
 533         "Set the NUMA policy");
 534     object_class_property_add_bool(oc, "share",
 535         host_memory_backend_get_share, host_memory_backend_set_share);
 536     object_class_property_set_description(oc, "share",
 537         "Mark the memory as private to QEMU or shared");
 538 #ifdef CONFIG_LINUX
 539     object_class_property_add_bool(oc, "reserve",
 540         host_memory_backend_get_reserve, host_memory_backend_set_reserve);
 541     object_class_property_set_description(oc, "reserve",
 542         "Reserve swap space (or huge pages) if applicable");
 543 #endif /* CONFIG_LINUX */
 544     /*
 545      * Do not delete/rename option. This option must be considered stable
 546      * (as if it didn't have the 'x-' prefix including deprecation period) as
 547      * long as 4.0 and older machine types exists.
 548      * Option will be used by upper layers to override (disable) canonical path
 549      * for ramblock-id set by compat properties on old machine types ( <= 4.0),
 550      * to keep migration working when backend is used for main RAM with
 551      * -machine memory-backend= option (main RAM historically used prefix-less
 552      * ramblock-id).
 553      */
 554     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
 555         host_memory_backend_get_use_canonical_path,
 556         host_memory_backend_set_use_canonical_path);
 557 }
 558
 559 static const TypeInfo host_memory_backend_info = {
 560     .name = TYPE_MEMORY_BACKEND,
 561     .parent = TYPE_OBJECT,
 562     .abstract = true,
 563     .class_size = sizeof(HostMemoryBackendClass),
 564     .class_init = host_memory_backend_class_init,
 565     .instance_size = sizeof(HostMemoryBackend),
 566     .instance_init = host_memory_backend_init,
 567     .instance_post_init = host_memory_backend_post_init,
 568     .interfaces = (InterfaceInfo[]) {
 569         { TYPE_USER_CREATABLE },
 570         { }
 571     }
 572 };
 573
 574 static void register_types(void)
 575 {
 576     type_register_static(&host_memory_backend_info);
 577 }
 578
 579 type_init(register_types);