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); 327