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     backend->aligned = true;
  84     name = host_memory_backend_get_name(backend);
  85     ram_flags = backend->share ? RAM_SHARED : 0;
  86     ram_flags |= fb->readonly ? RAM_READONLY_FD : 0;
  87     ram_flags |= fb->rom == ON_OFF_AUTO_ON ? RAM_READONLY : 0;
  88     ram_flags |= backend->reserve ? 0 : RAM_NORESERVE;
  89     ram_flags |= backend->guest_memfd ? RAM_GUEST_MEMFD : 0;
  90     ram_flags |= fb->is_pmem ? RAM_PMEM : 0;
  91     ram_flags |= RAM_NAMED_FILE;
  92     return memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name,
  93                                             backend->size, fb->align, ram_flags,
  94                                             fb->mem_path, fb->offset, errp);
  95 #endif
  96 }
  97
  98 static char *get_mem_path(Object *o, Error **errp)
  99 {
 100     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 101
 102     return g_strdup(fb->mem_path);
 103 }
 104
 105 static void set_mem_path(Object *o, const char *str, Error **errp)
 106 {
 107     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 108     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 109
 110     if (host_memory_backend_mr_inited(backend)) {
 111         error_setg(errp, "cannot change property 'mem-path' of %s",
 112                    object_get_typename(o));
 113         return;
 114     }
 115     g_free(fb->mem_path);
 116     fb->mem_path = g_strdup(str);
 117 }
 118
 119 static bool file_memory_backend_get_discard_data(Object *o, Error **errp)
 120 {
 121     return MEMORY_BACKEND_FILE(o)->discard_data;
 122 }
 123
 124 static void file_memory_backend_set_discard_data(Object *o, bool value,
 125                                                Error **errp)
 126 {
 127     MEMORY_BACKEND_FILE(o)->discard_data = value;
 128 }
 129
 130 static void file_memory_backend_get_align(Object *o, Visitor *v,
 131                                           const char *name, void *opaque,
 132                                           Error **errp)
 133 {
 134     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 135     uint64_t val = fb->align;
 136
 137     visit_type_size(v, name, &val, errp);
 138 }
 139
 140 static void file_memory_backend_set_align(Object *o, Visitor *v,
 141                                           const char *name, void *opaque,
 142                                           Error **errp)
 143 {
 144     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 145     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 146     uint64_t val;
 147
 148     if (host_memory_backend_mr_inited(backend)) {
 149         error_setg(errp, "cannot change property '%s' of %s", name,
 150                    object_get_typename(o));
 151         return;
 152     }
 153
 154     if (!visit_type_size(v, name, &val, errp)) {
 155         return;
 156     }
 157     fb->align = val;
 158 }
 159
 160 static void file_memory_backend_get_offset(Object *o, Visitor *v,
 161                                           const char *name, void *opaque,
 162                                           Error **errp)
 163 {
 164     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 165     uint64_t val = fb->offset;
 166
 167     visit_type_size(v, name, &val, errp);
 168 }
 169
 170 static void file_memory_backend_set_offset(Object *o, Visitor *v,
 171                                           const char *name, void *opaque,
 172                                           Error **errp)
 173 {
 174     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 175     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 176     uint64_t val;
 177
 178     if (host_memory_backend_mr_inited(backend)) {
 179         error_setg(errp, "cannot change property '%s' of %s", name,
 180                    object_get_typename(o));
 181         return;
 182     }
 183
 184     if (!visit_type_size(v, name, &val, errp)) {
 185         return;
 186     }
 187     fb->offset = val;
 188 }
 189
 190 #ifdef CONFIG_LIBPMEM
 191 static bool file_memory_backend_get_pmem(Object *o, Error **errp)
 192 {
 193     return MEMORY_BACKEND_FILE(o)->is_pmem;
 194 }
 195
 196 static void file_memory_backend_set_pmem(Object *o, bool value, Error **errp)
 197 {
 198     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 199     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 200
 201     if (host_memory_backend_mr_inited(backend)) {
 202         error_setg(errp, "cannot change property 'pmem' of %s.",
 203                    object_get_typename(o));
 204         return;
 205     }
 206
 207     fb->is_pmem = value;
 208 }
 209 #endif /* CONFIG_LIBPMEM */
 210
 211 static bool file_memory_backend_get_readonly(Object *obj, Error **errp)
 212 {
 213     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 214
 215     return fb->readonly;
 216 }
 217
 218 static void file_memory_backend_set_readonly(Object *obj, bool value,
 219                                              Error **errp)
 220 {
 221     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 222     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 223
 224     if (host_memory_backend_mr_inited(backend)) {
 225         error_setg(errp, "cannot change property 'readonly' of %s.",
 226                    object_get_typename(obj));
 227         return;
 228     }
 229
 230     fb->readonly = value;
 231 }
 232
 233 static void file_memory_backend_get_rom(Object *obj, Visitor *v,
 234                                         const char *name, void *opaque,
 235                                         Error **errp)
 236 {
 237     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 238     OnOffAuto rom = fb->rom;
 239
 240     visit_type_OnOffAuto(v, name, &rom, errp);
 241 }
 242
 243 static void file_memory_backend_set_rom(Object *obj, Visitor *v,
 244                                         const char *name, void *opaque,
 245                                         Error **errp)
 246 {
 247     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 248     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 249
 250     if (host_memory_backend_mr_inited(backend)) {
 251         error_setg(errp, "cannot change property '%s' of %s.", name,
 252                    object_get_typename(obj));
 253         return;
 254     }
 255
 256     visit_type_OnOffAuto(v, name, &fb->rom, errp);
 257 }
 258
 259 static void file_backend_unparent(Object *obj)
 260 {
 261     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 262     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(obj);
 263
 264     if (host_memory_backend_mr_inited(backend) && fb->discard_data) {
 265         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 266         uint64_t sz = memory_region_size(&backend->mr);
 267
 268         qemu_madvise(ptr, sz, QEMU_MADV_REMOVE);
 269     }
 270 }
 271
 272 static void
 273 file_backend_class_init(ObjectClass *oc, void *data)
 274 {
 275     HostMemoryBackendClass *bc = MEMORY_BACKEND_CLASS(oc);
 276
 277     bc->alloc = file_backend_memory_alloc;
 278     oc->unparent = file_backend_unparent;
 279
 280     object_class_property_add_bool(oc, "discard-data",
 281         file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
 282     object_class_property_add_str(oc, "mem-path",
 283         get_mem_path, set_mem_path);
 284     object_class_property_add(oc, "align", "int",
 285         file_memory_backend_get_align,
 286         file_memory_backend_set_align,
 287         NULL, NULL);
 288     object_class_property_add(oc, "offset", "int",
 289         file_memory_backend_get_offset,
 290         file_memory_backend_set_offset,
 291         NULL, NULL);
 292     object_class_property_set_description(oc, "offset",
 293         "Offset into the target file (ex: 1G)");
 294 #ifdef CONFIG_LIBPMEM
 295     object_class_property_add_bool(oc, "pmem",
 296         file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 297 #endif
 298     object_class_property_add_bool(oc, "readonly",
 299         file_memory_backend_get_readonly,
 300         file_memory_backend_set_readonly);
 301     object_class_property_add(oc, "rom", "OnOffAuto",
 302         file_memory_backend_get_rom, file_memory_backend_set_rom, NULL, NULL);
 303     object_class_property_set_description(oc, "rom",
 304         "Whether to create Read Only Memory (ROM)");
 305 }
 306
 307 static void file_backend_instance_finalize(Object *o)
 308 {
 309     HostMemoryBackendFile *fb = MEMORY_BACKEND_FILE(o);
 310
 311     g_free(fb->mem_path);
 312 }
 313
 314 static const TypeInfo file_backend_info = {
 315     .name = TYPE_MEMORY_BACKEND_FILE,
 316     .parent = TYPE_MEMORY_BACKEND,
 317     .class_init = file_backend_class_init,
 318     .instance_finalize = file_backend_instance_finalize,
 319     .instance_size = sizeof(HostMemoryBackendFile),
 320 };
 321
 322 static void register_types(void)
 323 {
 324     type_register_static(&file_backend_info);
 325 }
 326
 327 type_init(register_types);