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 #include "qemu/osdep.h"
  13 #include "sysemu/hostmem.h"
  14 #include "hw/boards.h"
  15 #include "qapi/error.h"
  16 #include "qapi/visitor.h"
  17 #include "qapi-visit.h"
  18 #include "qemu/config-file.h"
  19 #include "qom/object_interfaces.h"
  20
  21 #ifdef CONFIG_NUMA
  22 #include <numaif.h>
  23 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
  24 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
  25 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
  26 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
  27 #endif
  28
  29 static void
  30 host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
  31                              void *opaque, Error **errp)
  32 {
  33     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  34     uint64_t value = backend->size;
  35
  36     visit_type_size(v, name, &value, errp);
  37 }
  38
  39 static void
  40 host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
  41                              void *opaque, Error **errp)
  42 {
  43     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  44     Error *local_err = NULL;
  45     uint64_t value;
  46
  47     if (host_memory_backend_mr_inited(backend)) {
  48         error_setg(&local_err, "cannot change property value");
  49         goto out;
  50     }
  51
  52     visit_type_size(v, name, &value, &local_err);
  53     if (local_err) {
  54         goto out;
  55     }
  56     if (!value) {
  57         error_setg(&local_err, "Property '%s.%s' doesn't take value '%"
  58                    PRIu64 "'", object_get_typename(obj), name, value);
  59         goto out;
  60     }
  61     backend->size = value;
  62 out:
  63     error_propagate(errp, local_err);
  64 }
  65
  66 static void
  67 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
  68                                    void *opaque, Error **errp)
  69 {
  70     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  71     uint16List *host_nodes = NULL;
  72     uint16List **node = &host_nodes;
  73     unsigned long value;
  74
  75     value = find_first_bit(backend->host_nodes, MAX_NODES);
  76     if (value == MAX_NODES) {
  77         return;
  78     }
  79
  80     *node = g_malloc0(sizeof(**node));
  81     (*node)->value = value;
  82     node = &(*node)->next;
  83
  84     do {
  85         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
  86         if (value == MAX_NODES) {
  87             break;
  88         }
  89
  90         *node = g_malloc0(sizeof(**node));
  91         (*node)->value = value;
  92         node = &(*node)->next;
  93     } while (true);
  94
  95     visit_type_uint16List(v, name, &host_nodes, errp);
  96 }
  97
  98 static void
  99 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 100                                    void *opaque, Error **errp)
 101 {
 102 #ifdef CONFIG_NUMA
 103     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 104     uint16List *l = NULL;
 105
 106     visit_type_uint16List(v, name, &l, errp);
 107
 108     while (l) {
 109         bitmap_set(backend->host_nodes, l->value, 1);
 110         l = l->next;
 111     }
 112 #else
 113     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 114 #endif
 115 }
 116
 117 static int
 118 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
 119 {
 120     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 121     return backend->policy;
 122 }
 123
 124 static void
 125 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
 126 {
 127     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 128     backend->policy = policy;
 129
 130 #ifndef CONFIG_NUMA
 131     if (policy != HOST_MEM_POLICY_DEFAULT) {
 132         error_setg(errp, "NUMA policies are not supported by this QEMU");
 133     }
 134 #endif
 135 }
 136
 137 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
 138 {
 139     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 140
 141     return backend->merge;
 142 }
 143
 144 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
 145 {
 146     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 147
 148     if (!host_memory_backend_mr_inited(backend)) {
 149         backend->merge = value;
 150         return;
 151     }
 152
 153     if (value != backend->merge) {
 154         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 155         uint64_t sz = memory_region_size(&backend->mr);
 156
 157         qemu_madvise(ptr, sz,
 158                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
 159         backend->merge = value;
 160     }
 161 }
 162
 163 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
 164 {
 165     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 166
 167     return backend->dump;
 168 }
 169
 170 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
 171 {
 172     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 173
 174     if (!host_memory_backend_mr_inited(backend)) {
 175         backend->dump = value;
 176         return;
 177     }
 178
 179     if (value != backend->dump) {
 180         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 181         uint64_t sz = memory_region_size(&backend->mr);
 182
 183         qemu_madvise(ptr, sz,
 184                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
 185         backend->dump = value;
 186     }
 187 }
 188
 189 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
 190 {
 191     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 192
 193     return backend->prealloc || backend->force_prealloc;
 194 }
 195
 196 static void host_memory_backend_set_prealloc(Object *obj, bool value,
 197                                              Error **errp)
 198 {
 199     Error *local_err = NULL;
 200     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 201
 202     if (backend->force_prealloc) {
 203         if (value) {
 204             error_setg(errp,
 205                        "remove -mem-prealloc to use the prealloc property");
 206             return;
 207         }
 208     }
 209
 210     if (!host_memory_backend_mr_inited(backend)) {
 211         backend->prealloc = value;
 212         return;
 213     }
 214
 215     if (value && !backend->prealloc) {
 216         int fd = memory_region_get_fd(&backend->mr);
 217         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 218         uint64_t sz = memory_region_size(&backend->mr);
 219
 220         os_mem_prealloc(fd, ptr, sz, smp_cpus, &local_err);
 221         if (local_err) {
 222             error_propagate(errp, local_err);
 223             return;
 224         }
 225         backend->prealloc = true;
 226     }
 227 }
 228
 229 static void host_memory_backend_init(Object *obj)
 230 {
 231     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 232     MachineState *machine = MACHINE(qdev_get_machine());
 233
 234     backend->merge = machine_mem_merge(machine);
 235     backend->dump = machine_dump_guest_core(machine);
 236     backend->prealloc = mem_prealloc;
 237 }
 238
 239 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
 240 {
 241     /*
 242      * NOTE: We forbid zero-length memory backend, so here zero means
 243      * "we haven't inited the backend memory region yet".
 244      */
 245     return memory_region_size(&backend->mr) != 0;
 246 }
 247
 248 MemoryRegion *
 249 host_memory_backend_get_memory(HostMemoryBackend *backend, Error **errp)
 250 {
 251     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
 252 }
 253
 254 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
 255 {
 256     backend->is_mapped = mapped;
 257 }
 258
 259 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
 260 {
 261     return backend->is_mapped;
 262 }
 263
 264 static void
 265 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
 266 {
 267     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
 268     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
 269     Error *local_err = NULL;
 270     void *ptr;
 271     uint64_t sz;
 272
 273     if (bc->alloc) {
 274         bc->alloc(backend, &local_err);
 275         if (local_err) {
 276             goto out;
 277         }
 278
 279         ptr = memory_region_get_ram_ptr(&backend->mr);
 280         sz = memory_region_size(&backend->mr);
 281
 282         if (backend->merge) {
 283             qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
 284         }
 285         if (!backend->dump) {
 286             qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
 287         }
 288 #ifdef CONFIG_NUMA
 289         unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
 290         /* lastbit == MAX_NODES means maxnode = 0 */
 291         unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
 292         /* ensure policy won't be ignored in case memory is preallocated
 293          * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
 294          * this doesn't catch hugepage case. */
 295         unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
 296
 297         /* check for invalid host-nodes and policies and give more verbose
 298          * error messages than mbind(). */
 299         if (maxnode && backend->policy == MPOL_DEFAULT) {
 300             error_setg(errp, "host-nodes must be empty for policy default,"
 301                        " or you should explicitly specify a policy other"
 302                        " than default");
 303             return;
 304         } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
 305             error_setg(errp, "host-nodes must be set for policy %s",
 306                        HostMemPolicy_str(backend->policy));
 307             return;
 308         }
 309
 310         /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
 311          * as argument to mbind() due to an old Linux bug (feature?) which
 312          * cuts off the last specified node. This means backend->host_nodes
 313          * must have MAX_NODES+1 bits available.
 314          */
 315         assert(sizeof(backend->host_nodes) >=
 316                BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
 317         assert(maxnode <= MAX_NODES);
 318         if (mbind(ptr, sz, backend->policy,
 319                   maxnode ? backend->host_nodes : NULL, maxnode + 1, flags)) {
 320             if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
 321                 error_setg_errno(errp, errno,
 322                                  "cannot bind memory to host NUMA nodes");
 323                 return;
 324             }
 325         }
 326 #endif
 327         /* Preallocate memory after the NUMA policy has been instantiated.
 328          * This is necessary to guarantee memory is allocated with
 329          * specified NUMA policy in place.
 330          */
 331         if (backend->prealloc) {
 332             os_mem_prealloc(memory_region_get_fd(&backend->mr), ptr, sz,
 333                             smp_cpus, &local_err);
 334             if (local_err) {
 335                 goto out;
 336             }
 337         }
 338     }
 339 out:
 340     error_propagate(errp, local_err);
 341 }
 342
 343 static bool
 344 host_memory_backend_can_be_deleted(UserCreatable *uc)
 345 {
 346     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
 347         return false;
 348     } else {
 349         return true;
 350     }
 351 }
 352
 353 static char *get_id(Object *o, Error **errp)
 354 {
 355     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 356
 357     return g_strdup(backend->id);
 358 }
 359
 360 static void set_id(Object *o, const char *str, Error **errp)
 361 {
 362     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 363
 364     if (backend->id) {
 365         error_setg(errp, "cannot change property value");
 366         return;
 367     }
 368     backend->id = g_strdup(str);
 369 }
 370
 371 static bool host_memory_backend_get_share(Object *o, Error **errp)
 372 {
 373     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 374
 375     return backend->share;
 376 }
 377
 378 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
 379 {
 380     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 381
 382     if (host_memory_backend_mr_inited(backend)) {
 383         error_setg(errp, "cannot change property value");
 384         return;
 385     }
 386     backend->share = value;
 387 }
 388
 389 static void
 390 host_memory_backend_class_init(ObjectClass *oc, void *data)
 391 {
 392     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 393
 394     ucc->complete = host_memory_backend_memory_complete;
 395     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
 396
 397     object_class_property_add_bool(oc, "merge",
 398         host_memory_backend_get_merge,
 399         host_memory_backend_set_merge, &error_abort);
 400     object_class_property_add_bool(oc, "dump",
 401         host_memory_backend_get_dump,
 402         host_memory_backend_set_dump, &error_abort);
 403     object_class_property_add_bool(oc, "prealloc",
 404         host_memory_backend_get_prealloc,
 405         host_memory_backend_set_prealloc, &error_abort);
 406     object_class_property_add(oc, "size", "int",
 407         host_memory_backend_get_size,
 408         host_memory_backend_set_size,
 409         NULL, NULL, &error_abort);
 410     object_class_property_add(oc, "host-nodes", "int",
 411         host_memory_backend_get_host_nodes,
 412         host_memory_backend_set_host_nodes,
 413         NULL, NULL, &error_abort);
 414     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
 415         &HostMemPolicy_lookup,
 416         host_memory_backend_get_policy,
 417         host_memory_backend_set_policy, &error_abort);
 418     object_class_property_add_str(oc, "id", get_id, set_id, &error_abort);
 419     object_class_property_add_bool(oc, "share",
 420         host_memory_backend_get_share, host_memory_backend_set_share,
 421         &error_abort);
 422 }
 423
 424 static void host_memory_backend_finalize(Object *o)
 425 {
 426     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 427     g_free(backend->id);
 428 }
 429
 430 static const TypeInfo host_memory_backend_info = {
 431     .name = TYPE_MEMORY_BACKEND,
 432     .parent = TYPE_OBJECT,
 433     .abstract = true,
 434     .class_size = sizeof(HostMemoryBackendClass),
 435     .class_init = host_memory_backend_class_init,
 436     .instance_size = sizeof(HostMemoryBackend),
 437     .instance_init = host_memory_backend_init,
 438     .instance_finalize = host_memory_backend_finalize,
 439     .interfaces = (InterfaceInfo[]) {
 440         { TYPE_USER_CREATABLE },
 441         { }
 442     }
 443 };
 444
 445 static void register_types(void)
 446 {
 447     type_register_static(&host_memory_backend_info);
 448 }
 449
 450 type_init(register_types);