backends/hostmem-file.c

   1 /*
   2  * QEMU Host Memory Backend for hugetlbfs
   3  *
   4  * Copyright (C) 2013-2014 Red Hat Inc
   5  *
   6  * Authors:
   7  *   Paolo Bonzini <pbonzini@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 "qapi/error.h"
  15 #include "qemu/error-report.h"
  16 #include "qemu/module.h"
  17 #include "qemu/madvise.h"
  18 #include "sysemu/hostmem.h"
  19 #include "qom/object_interfaces.h"
  20 #include "qom/object.h"
  21 #include "qapi/visitor.h"
  22 #include "qapi/qapi-visit-common.h"
  23
  24 OBJECT_DECLARE_SIMPLE_TYPE(HostMemoryBackendFile, MEMORY_BACKEND_FILE)
  25
  26
  27 struct HostMemoryBackendFile {
  28     HostMemoryBackend parent_obj;
  29
  30     char *mem_path;
  31     uint64_t align;
  32     uint64_t offset;
  33     bool discard_data;
  34     bool is_pmem;
  35     bool readonly;
  36     OnOffAuto rom;
  37 };
  38
  39 static void
  40 file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp)
  41 {
  42 #ifndef CONFIG_POSIX
  43     error_setg(errp, "backend '%s' not supported on this host",
  44                object_get_typename(OBJECT(backend)));
  45 #else
  46     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(backend);
  47     g_autofree gchar *name = NULL;
  48     uint32_t ram_flags;
  49
  50     if (!backend->size) {
  51         error_setg(errp, "can't create backend with size 0");
  52         return;
  53     }
  54     if (!fb->mem_path) {
  55         error_setg(errp, "mem-path property not set");
  56         return;
  57     }
  58
  59     switch (fb->rom) {
  60     case ON_OFF_AUTO_AUTO:
  61         /* Traditionally, opening the file readonly always resulted in ROM. */
  62         fb->rom = fb->readonly ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
  63         break;
  64     case ON_OFF_AUTO_ON:
  65         if (!fb->readonly) {
  66             error_setg(errp, "property 'rom' = 'on' is not supported with"
  67                        " 'readonly' = 'off'");
  68             return;
  69         }
  70         break;
  71     case ON_OFF_AUTO_OFF:
  72         if (fb->readonly && backend->share) {
  73             error_setg(errp, "property 'rom' = 'off' is incompatible with"
  74                        " 'readonly' = 'on' and 'share' = 'on'");
  75             return;
  76         }
  77         break;
  78     default:
  79         assert(false);
  80     }
  81
  82     name = host_memory_backend_get_name(backend);
  83     ram_flags = backend->share ? RAM_SHARED : 0;
  84     ram_flags |= fb->readonly ? RAM_READONLY_FD : 0;
  85     ram_flags |= fb->rom == ON_OFF_AUTO_ON ? RAM_READONLY : 0;
  86     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
  87     ram_flags |= fb->is_pmem ? RAM_PMEM : 0;
  88     ram_flags |= RAM_NAMED_FILE;
  89     memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
  90                                      backend->size, fb->align, ram_flags,
  91                                      fb->mem_path, fb->offset, errp);
  92 #endif
  93 }
  94
  95 static char *get_mem_path(Object *o, Error **errp)
  96 {
  97     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
  98
  99     return g_strdup(fb->mem_path);
 100 }
 101
 102 static void set_mem_path(Object *o, const char *str, Error **errp)
 103 {
 104     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 105     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 106
 107     if (host_memory_backend_mr_inited(backend)) {
 108         error_setg(errp, "cannot change property 'mem-path' of %s",
 109                    object_get_typename(o));
 110         return;
 111     }
 112     g_free(fb->mem_path);
 113     fb->mem_path = g_strdup(str);
 114 }
 115
 116 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
 117 {
 118     return MEMORY_BACKEND_FILE(o)->discard_data;
 119 }
 120
 121 static void file_memory_backend_set_discard_data(Object *o, bool value,
 122                                                Error **errp)
 123 {
 124     MEMORY_BACKEND_FILE(o)->discard_data = value;
 125 }
 126
 127 static void file_memory_backend_get_align(Object *o, Visitor *v,
 128                                           const char *name, void *opaque,
 129                                           Error **errp)
 130 {
 131     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 132     uint64_t val = fb->align;
 133
 134     visit_type_size(v, name, &val, errp);
 135 }
 136
 137 static void file_memory_backend_set_align(Object *o, Visitor *v,
 138                                           const char *name, void *opaque,
 139                                           Error **errp)
 140 {
 141     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 142     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 143     uint64_t val;
 144
 145     if (host_memory_backend_mr_inited(backend)) {
 146         error_setg(errp, "cannot change property '%s' of %s", name,
 147                    object_get_typename(o));
 148         return;
 149     }
 150
 151     if (!visit_type_size(v, name, &val, errp)) {
 152         return;
 153     }
 154     fb->align = val;
 155 }
 156
 157 static void file_memory_backend_get_offset(Object *o, Visitor *v,
 158                                           const char *name, void *opaque,
 159                                           Error **errp)
 160 {
 161     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 162     uint64_t val = fb->offset;
 163
 164     visit_type_size(v, name, &val, errp);
 165 }
 166
 167 static void file_memory_backend_set_offset(Object *o, Visitor *v,
 168                                           const char *name, void *opaque,
 169                                           Error **errp)
 170 {
 171     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 172     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 173     uint64_t val;
 174
 175     if (host_memory_backend_mr_inited(backend)) {
 176         error_setg(errp, "cannot change property '%s' of %s", name,
 177                    object_get_typename(o));
 178         return;
 179     }
 180
 181     if (!visit_type_size(v, name, &val, errp)) {
 182         return;
 183     }
 184     fb->offset = val;
 185 }
 186
 187 #ifdef CONFIG_LIBPMEM
 188 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 189 {
 190     return MEMORY_BACKEND_FILE(o)->is_pmem;
 191 }
 192
 193 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 194 {
 195     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 196     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 197
 198     if (host_memory_backend_mr_inited(backend)) {
 199         error_setg(errp, "cannot change property 'pmem' of %s.",
 200                    object_get_typename(o));
 201         return;
 202     }
 203
 204     fb->is_pmem = value;
 205 }
 206 #endif /* CONFIG_LIBPMEM */
 207
 208 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
 209 {
 210     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 211
 212     return fb->readonly;
 213 }
 214
 215 static void file_memory_backend_set_readonly(Object *obj, bool value,
 216                                              Error **errp)
 217 {
 218     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 219     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 220
 221     if (host_memory_backend_mr_inited(backend)) {
 222         error_setg(errp, "cannot change property 'readonly' of %s.",
 223                    object_get_typename(obj));
 224         return;
 225     }
 226
 227     fb->readonly = value;
 228 }
 229
 230 static void file_memory_backend_get_rom(Object *obj, Visitor *v,
 231                                         const char *name, void *opaque,
 232                                         Error **errp)
 233 {
 234     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 235     OnOffAuto rom = fb->rom;
 236
 237     visit_type_OnOffAuto(v, name, &rom, errp);
 238 }
 239
 240 static void file_memory_backend_set_rom(Object *obj, Visitor *v,
 241                                         const char *name, void *opaque,
 242                                         Error **errp)
 243 {
 244     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 245     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 246
 247     if (host_memory_backend_mr_inited(backend)) {
 248         error_setg(errp, "cannot change property '%s' of %s.", name,
 249                    object_get_typename(obj));
 250         return;
 251     }
 252
 253     visit_type_OnOffAuto(v, name, &fb->rom, errp);
 254 }
 255
 256 static void file_backend_unparent(Object *obj)
 257 {
 258     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 259     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 260
 261     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 262         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 263         uint64_t sz = memory_region_size(&backend->mr);
 264
 265         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 266     }
 267 }
 268
 269 static void
 270 file_backend_class_init(ObjectClass *oc, void *data)
 271 {
 272     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 273
 274     bc->alloc = file_backend_memory_alloc;
 275     oc->unparent = file_backend_unparent;
 276
 277     object_class_property_add_bool(oc, "discard-data",
 278         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
 279     object_class_property_add_str(oc, "mem-path",
 280         get_mem_path, set_mem_path);
 281     object_class_property_add(oc, "align", "int",
 282         file_memory_backend_get_align,
 283         file_memory_backend_set_align,
 284         NULL, NULL);
 285     object_class_property_add(oc, "offset", "int",
 286         file_memory_backend_get_offset,
 287         file_memory_backend_set_offset,
 288         NULL, NULL);
 289     object_class_property_set_description(oc, "offset",
 290         "Offset into the target file (ex: 1G)");
 291 #ifdef CONFIG_LIBPMEM
 292     object_class_property_add_bool(oc, "pmem",
 293         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 294 #endif
 295     object_class_property_add_bool(oc, "readonly",
 296         file_memory_backend_get_readonly,
 297         file_memory_backend_set_readonly);
 298     object_class_property_add(oc, "rom", "OnOffAuto",
 299         file_memory_backend_get_rom, file_memory_backend_set_rom, NULL, NULL);
 300     object_class_property_set_description(oc, "rom",
 301         "Whether to create Read Only Memory (ROM)");
 302 }
 303
 304 static void file_backend_instance_finalize(Object *o)
 305 {
 306     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 307
 308     g_free(fb->mem_path);
 309 }
 310
 311 static const TypeInfo file_backend_info = {
 312     .name = TYPE_MEMORY_BACKEND_FILE,
 313     .parent = TYPE_MEMORY_BACKEND,
 314     .class_init = file_backend_class_init,
 315     .instance_finalize = file_backend_instance_finalize,
 316     .instance_size = sizeof(HostMemoryBackendFile),
 317 };
 318
 319 static void register_types(void)
 320 {
 321     type_register_static(&file_backend_info);
 322 }
 323
 324 type_init(register_types);