| 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 "system/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 : RAM_PRIVATE; |
| 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, const 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); |