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); 328