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 "sysemu/sysemu.h"
  16 #include "hw/boards.h"
  17 #include "qapi/error.h"
  18 #include "qapi/qapi-builtin-visit.h"
  19 #include "qapi/visitor.h"
  20 #include "qemu/config-file.h"
  21 #include "qom/object_interfaces.h"
  22 #include "qemu/mmap-alloc.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 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     Error *local_err = NULL;
  58     uint64_t value;
  59
  60     if (host_memory_backend_mr_inited(backend)) {
  61         error_setg(&local_err, "cannot change property %s of %s ",
  62                    name, object_get_typename(obj));
  63         goto out;
  64     }
  65
  66     visit_type_size(v, name, &value, &local_err);
  67     if (local_err) {
  68         goto out;
  69     }
  70     if (!value) {
  71         error_setg(&local_err,
  72                    "property '%s' of %s doesn't take value '%" PRIu64 "'",
  73                    name, object_get_typename(obj), value);
  74         goto out;
  75     }
  76     backend->size = value;
  77 out:
  78     error_propagate(errp, local_err);
  79 }
  80
  81 static void
  82 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
  83                                    void *opaque, Error **errp)
  84 {
  85     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  86     uint16List *host_nodes = NULL;
  87     uint16List **node = &host_nodes;
  88     unsigned long value;
  89
  90     value = find_first_bit(backend->host_nodes, MAX_NODES);
  91     if (value == MAX_NODES) {
  92         goto ret;
  93     }
  94
  95     *node = g_malloc0(sizeof(**node));
  96     (*node)->value = value;
  97     node = &(*node)->next;
  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         *node = g_malloc0(sizeof(**node));
 106         (*node)->value = value;
 107         node = &(*node)->next;
 108     } while (true);
 109
 110 ret:
 111     visit_type_uint16List(v, name, &host_nodes, errp);
 112 }
 113
 114 static void
 115 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 116                                    void *opaque, Error **errp)
 117 {
 118 #ifdef CONFIG_NUMA
 119     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 120     uint16List *l, *host_nodes = NULL;
 121
 122     visit_type_uint16List(v, name, &host_nodes, errp);
 123
 124     for (l = host_nodes; l; l = l->next) {
 125         if (l->value >= MAX_NODES) {
 126             error_setg(errp, "Invalid host-nodes value: %d", l->value);
 127             goto out;
 128         }
 129     }
 130
 131     for (l = host_nodes; l; l = l->next) {
 132         bitmap_set(backend->host_nodes, l->value, 1);
 133     }
 134
 135 out:
 136     qapi_free_uint16List(host_nodes);
 137 #else
 138     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 139 #endif
 140 }
 141
 142 static int
 143 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
 144 {
 145     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 146     return backend->policy;
 147 }
 148
 149 static void
 150 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
 151 {
 152     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 153     backend->policy = policy;
 154
 155 #ifndef CONFIG_NUMA
 156     if (policy != HOST_MEM_POLICY_DEFAULT) {
 157         error_setg(errp, "NUMA policies are not supported by this QEMU");
 158     }
 159 #endif
 160 }
 161
 162 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
 163 {
 164     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 165
 166     return backend->merge;
 167 }
 168
 169 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
 170 {
 171     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 172
 173     if (!host_memory_backend_mr_inited(backend)) {
 174         backend->merge = value;
 175         return;
 176     }
 177
 178     if (value != backend->merge) {
 179         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 180         uint64_t sz = memory_region_size(&backend->mr);
 181
 182         qemu_madvise(ptr, sz,
 183                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
 184         backend->merge = value;
 185     }
 186 }
 187
 188 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
 189 {
 190     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 191
 192     return backend->dump;
 193 }
 194
 195 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
 196 {
 197     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 198
 199     if (!host_memory_backend_mr_inited(backend)) {
 200         backend->dump = value;
 201         return;
 202     }
 203
 204     if (value != backend->dump) {
 205         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 206         uint64_t sz = memory_region_size(&backend->mr);
 207
 208         qemu_madvise(ptr, sz,
 209                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
 210         backend->dump = value;
 211     }
 212 }
 213
 214 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
 215 {
 216     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 217
 218     return backend->prealloc || backend->force_prealloc;
 219 }
 220
 221 static void host_memory_backend_set_prealloc(Object *obj, bool value,
 222                                              Error **errp)
 223 {
 224     Error *local_err = NULL;
 225     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 226     MachineState *ms = MACHINE(qdev_get_machine());
 227
 228     if (backend->force_prealloc) {
 229         if (value) {
 230             error_setg(errp,
 231                        "remove -mem-prealloc to use the prealloc property");
 232             return;
 233         }
 234     }
 235
 236     if (!host_memory_backend_mr_inited(backend)) {
 237         backend->prealloc = value;
 238         return;
 239     }
 240
 241     if (value && !backend->prealloc) {
 242         int fd = memory_region_get_fd(&backend->mr);
 243         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 244         uint64_t sz = memory_region_size(&backend->mr);
 245
 246         os_mem_prealloc(fd, ptr, sz, ms->smp.cpus, &local_err);
 247         if (local_err) {
 248             error_propagate(errp, local_err);
 249             return;
 250         }
 251         backend->prealloc = true;
 252     }
 253 }
 254
 255 static void host_memory_backend_init(Object *obj)
 256 {
 257     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 258     MachineState *machine = MACHINE(qdev_get_machine());
 259
 260     backend->merge = machine_mem_merge(machine);
 261     backend->dump = machine_dump_guest_core(machine);
 262     backend->prealloc = mem_prealloc;
 263 }
 264
 265 static void host_memory_backend_post_init(Object *obj)
 266 {
 267     object_apply_compat_props(obj);
 268 }
 269
 270 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
 271 {
 272     /*
 273      * NOTE: We forbid zero-length memory backend, so here zero means
 274      * "we haven't inited the backend memory region yet".
 275      */
 276     return memory_region_size(&backend->mr) != 0;
 277 }
 278
 279 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
 280 {
 281     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
 282 }
 283
 284 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
 285 {
 286     backend->is_mapped = mapped;
 287 }
 288
 289 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
 290 {
 291     return backend->is_mapped;
 292 }
 293
 294 #ifdef __linux__
 295 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
 296 {
 297     Object *obj = OBJECT(memdev);
 298     char *path = object_property_get_str(obj, "mem-path", NULL);
 299     size_t pagesize = qemu_mempath_getpagesize(path);
 300
 301     g_free(path);
 302     return pagesize;
 303 }
 304 #else
 305 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
 306 {
 307     return qemu_real_host_page_size;
 308 }
 309 #endif
 310
 311 static void
 312 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
 313 {
 314     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
 315     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
 316     MachineState *ms = MACHINE(qdev_get_machine());
 317     Error *local_err = NULL;
 318     void *ptr;
 319     uint64_t sz;
 320
 321     if (bc->alloc) {
 322         bc->alloc(backend, &local_err);
 323         if (local_err) {
 324             goto out;
 325         }
 326
 327         ptr = memory_region_get_ram_ptr(&backend->mr);
 328         sz = memory_region_size(&backend->mr);
 329
 330         if (backend->merge) {
 331             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
 332         }
 333         if (!backend->dump) {
 334             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
 335         }
 336 #ifdef CONFIG_NUMA
 337         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
 338         /* lastbit == MAX_NODES means maxnode = 0 */
 339         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
 340         /* ensure policy won't be ignored in case memory is preallocated
 341          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
 342          * this doesn't catch hugepage case. */
 343         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
 344
 345         /* check for invalid host-nodes and policies and give more verbose
 346          * error messages than mbind(). */
 347         if (maxnode && backend->policy == MPOL_DEFAULT) {
 348             error_setg(errp, "host-nodes must be empty for policy default,"
 349                        " or you should explicitly specify a policy other"
 350                        " than default");
 351             return;
 352         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
 353             error_setg(errp, "host-nodes must be set for policy %s",
 354                        HostMemPolicy_str(backend->policy));
 355             return;
 356         }
 357
 358         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
 359          * as argument to mbind() due to an old Linux bug (feature?) which
 360          * cuts off the last specified node. This means backend->host_nodes
 361          * must have MAX_NODES+1 bits available.
 362          */
 363         assert(sizeof(backend->host_nodes) >=
 364                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
 365         assert(maxnode <= MAX_NODES);
 366         if (mbind(ptr, sz, backend->policy,
 367                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
 368             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
 369                 error_setg_errno(errp, errno,
 370                                  "cannot bind memory to host NUMA nodes");
 371                 return;
 372             }
 373         }
 374 #endif
 375         /* Preallocate memory after the NUMA policy has been instantiated.
 376          * This is necessary to guarantee memory is allocated with
 377          * specified NUMA policy in place.
 378          */
 379         if (backend->prealloc) {
 380             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
 381                             ms->smp.cpus, &local_err);
 382             if (local_err) {
 383                 goto out;
 384             }
 385         }
 386     }
 387 out:
 388     error_propagate(errp, local_err);
 389 }
 390
 391 static bool
 392 host_memory_backend_can_be_deleted(UserCreatable *uc)
 393 {
 394     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
 395         return false;
 396     } else {
 397         return true;
 398     }
 399 }
 400
 401 static bool host_memory_backend_get_share(Object *o, Error **errp)
 402 {
 403     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 404
 405     return backend->share;
 406 }
 407
 408 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
 409 {
 410     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 411
 412     if (host_memory_backend_mr_inited(backend)) {
 413         error_setg(errp, "cannot change property value");
 414         return;
 415     }
 416     backend->share = value;
 417 }
 418
 419 static bool
 420 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
 421 {
 422     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 423
 424     return backend->use_canonical_path;
 425 }
 426
 427 static void
 428 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
 429                                            Error **errp)
 430 {
 431     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 432
 433     backend->use_canonical_path = value;
 434 }
 435
 436 static void
 437 host_memory_backend_class_init(ObjectClass *oc, void *data)
 438 {
 439     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 440
 441     ucc->complete = host_memory_backend_memory_complete;
 442     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
 443
 444     object_class_property_add_bool(oc, "merge",
 445         host_memory_backend_get_merge,
 446         host_memory_backend_set_merge, &error_abort);
 447     object_class_property_set_description(oc, "merge",
 448         "Mark memory as mergeable", &error_abort);
 449     object_class_property_add_bool(oc, "dump",
 450         host_memory_backend_get_dump,
 451         host_memory_backend_set_dump, &error_abort);
 452     object_class_property_set_description(oc, "dump",
 453         "Set to 'off' to exclude from core dump", &error_abort);
 454     object_class_property_add_bool(oc, "prealloc",
 455         host_memory_backend_get_prealloc,
 456         host_memory_backend_set_prealloc, &error_abort);
 457     object_class_property_set_description(oc, "prealloc",
 458         "Preallocate memory", &error_abort);
 459     object_class_property_add(oc, "size", "int",
 460         host_memory_backend_get_size,
 461         host_memory_backend_set_size,
 462         NULL, NULL, &error_abort);
 463     object_class_property_set_description(oc, "size",
 464         "Size of the memory region (ex: 500M)", &error_abort);
 465     object_class_property_add(oc, "host-nodes", "int",
 466         host_memory_backend_get_host_nodes,
 467         host_memory_backend_set_host_nodes,
 468         NULL, NULL, &error_abort);
 469     object_class_property_set_description(oc, "host-nodes",
 470         "Binds memory to the list of NUMA host nodes", &error_abort);
 471     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
 472         &HostMemPolicy_lookup,
 473         host_memory_backend_get_policy,
 474         host_memory_backend_set_policy, &error_abort);
 475     object_class_property_set_description(oc, "policy",
 476         "Set the NUMA policy", &error_abort);
 477     object_class_property_add_bool(oc, "share",
 478         host_memory_backend_get_share, host_memory_backend_set_share,
 479         &error_abort);
 480     object_class_property_set_description(oc, "share",
 481         "Mark the memory as private to QEMU or shared", &error_abort);
 482     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
 483         host_memory_backend_get_use_canonical_path,
 484         host_memory_backend_set_use_canonical_path, &error_abort);
 485 }
 486
 487 static const TypeInfo host_memory_backend_info = {
 488     .name = TYPE_MEMORY_BACKEND,
 489     .parent = TYPE_OBJECT,
 490     .abstract = true,
 491     .class_size = sizeof(HostMemoryBackendClass),
 492     .class_init = host_memory_backend_class_init,
 493     .instance_size = sizeof(HostMemoryBackend),
 494     .instance_init = host_memory_backend_init,
 495     .instance_post_init = host_memory_backend_post_init,
 496     .interfaces = (InterfaceInfo[]) {
 497         { TYPE_USER_CREATABLE },
 498         { }
 499     }
 500 };
 501
 502 static void register_types(void)
 503 {
 504     type_register_static(&host_memory_backend_info);
 505 }
 506
 507 type_init(register_types);