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