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