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