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