| 1 | /* |
| 2 | * Privileged RAPL MSR helper commands for QEMU |
| 3 | * |
| 4 | * Copyright (C) 2024 Red Hat, Inc. <aharivel@redhat.com> |
| 5 | * |
| 6 | * Author: Anthony Harivel <aharivel@redhat.com> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation; under version 2 of the License. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| 19 | */ |
| 20 | |
| 21 | #include "qemu/osdep.h" |
| 22 | #include <getopt.h> |
| 23 | #include <sys/ioctl.h> |
| 24 | #ifdef CONFIG_LIBCAP_NG |
| 25 | #include <cap-ng.h> |
| 26 | #endif |
| 27 | #include <pwd.h> |
| 28 | #include <grp.h> |
| 29 | |
| 30 | #include "qemu/help-texts.h" |
| 31 | #include "qapi/error.h" |
| 32 | #include "qemu/cutils.h" |
| 33 | #include "qemu/main-loop.h" |
| 34 | #include "qemu/module.h" |
| 35 | #include "qemu/error-report.h" |
| 36 | #include "qemu/config-file.h" |
| 37 | #include "qemu-version.h" |
| 38 | #include "qapi/error.h" |
| 39 | #include "qemu/error-report.h" |
| 40 | #include "qemu/log.h" |
| 41 | #include "qemu/systemd.h" |
| 42 | #include "io/channel.h" |
| 43 | #include "io/channel-socket.h" |
| 44 | #include "trace/control.h" |
| 45 | #include "qemu-version.h" |
| 46 | #include "rapl-msr-index.h" |
| 47 | |
| 48 | #define MSR_PATH_TEMPLATE "/dev/cpu/%u/msr" |
| 49 | |
| 50 | static char *socket_path; |
| 51 | static char *pidfile; |
| 52 | static enum { RUNNING, TERMINATE, TERMINATING } state; |
| 53 | static QIOChannelSocket *server_ioc; |
| 54 | static int server_watch; |
| 55 | static int num_active_sockets = 1; |
| 56 | static bool verbose; |
| 57 | |
| 58 | #ifdef CONFIG_LIBCAP_NG |
| 59 | static int uid = -1; |
| 60 | static int gid = -1; |
| 61 | #endif |
| 62 | |
| 63 | static void compute_default_paths(void) |
| 64 | { |
| 65 | g_autofree char *state = qemu_get_local_state_dir(); |
| 66 | |
| 67 | socket_path = g_build_filename(state, "run", "qemu-vmsr-helper.sock", NULL); |
| 68 | pidfile = g_build_filename(state, "run", "qemu-vmsr-helper.pid", NULL); |
| 69 | } |
| 70 | |
| 71 | static int is_intel_processor(void) |
| 72 | { |
| 73 | int ebx, ecx, edx; |
| 74 | |
| 75 | /* Execute CPUID instruction with eax=0 (basic identification) */ |
| 76 | asm volatile ( |
| 77 | "cpuid" |
| 78 | : "=b" (ebx), "=c" (ecx), "=d" (edx) |
| 79 | : "a" (0) |
| 80 | ); |
| 81 | |
| 82 | /* |
| 83 | * Check if processor is "GenuineIntel" |
| 84 | * 0x756e6547 = "Genu" |
| 85 | * 0x49656e69 = "ineI" |
| 86 | * 0x6c65746e = "ntel" |
| 87 | */ |
| 88 | return (ebx == 0x756e6547) && (edx == 0x49656e69) && (ecx == 0x6c65746e); |
| 89 | } |
| 90 | |
| 91 | static int is_rapl_enabled(void) |
| 92 | { |
| 93 | const char *path = "/sys/class/powercap/intel-rapl/enabled"; |
| 94 | FILE *file = fopen(path, "r"); |
| 95 | int value = 0; |
| 96 | |
| 97 | if (file != NULL) { |
| 98 | if (fscanf(file, "%d", &value) != 1) { |
| 99 | error_report("INTEL RAPL not enabled"); |
| 100 | } |
| 101 | fclose(file); |
| 102 | } else { |
| 103 | error_report("Error opening %s", path); |
| 104 | } |
| 105 | |
| 106 | return value; |
| 107 | } |
| 108 | |
| 109 | /* |
| 110 | * Check if the TID that request the MSR read |
| 111 | * belongs to the peer. It be should a TID of a vCPU. |
| 112 | */ |
| 113 | static bool is_tid_present(pid_t pid, pid_t tid) |
| 114 | { |
| 115 | g_autofree char *tidPath = g_strdup_printf("/proc/%d/task/%d", pid, tid); |
| 116 | |
| 117 | /* Check if the TID directory exists within the PID directory */ |
| 118 | if (access(tidPath, F_OK) == 0) { |
| 119 | return true; |
| 120 | } |
| 121 | |
| 122 | error_report("Failed to open /proc at %s", tidPath); |
| 123 | return false; |
| 124 | } |
| 125 | |
| 126 | /* |
| 127 | * Only the RAPL MSR in target/i386/cpu.h are allowed |
| 128 | */ |
| 129 | static bool is_msr_allowed(uint32_t reg) |
| 130 | { |
| 131 | switch (reg) { |
| 132 | case MSR_RAPL_POWER_UNIT: |
| 133 | case MSR_PKG_POWER_LIMIT: |
| 134 | case MSR_PKG_ENERGY_STATUS: |
| 135 | case MSR_PKG_POWER_INFO: |
| 136 | return true; |
| 137 | default: |
| 138 | return false; |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | static uint64_t vmsr_read_msr(uint32_t msr_register, unsigned int cpu_id) |
| 143 | { |
| 144 | int fd; |
| 145 | uint64_t result = 0; |
| 146 | |
| 147 | g_autofree char *path = g_strdup_printf(MSR_PATH_TEMPLATE, cpu_id); |
| 148 | |
| 149 | fd = open(path, O_RDONLY); |
| 150 | if (fd < 0) { |
| 151 | error_report("Failed to open MSR file at %s", path); |
| 152 | return result; |
| 153 | } |
| 154 | |
| 155 | if (pread(fd, &result, sizeof(result), msr_register) != sizeof(result)) { |
| 156 | error_report("Failed to read MSR"); |
| 157 | result = 0; |
| 158 | } |
| 159 | |
| 160 | close(fd); |
| 161 | return result; |
| 162 | } |
| 163 | |
| 164 | static void usage(const char *name) |
| 165 | { |
| 166 | (printf) ( |
| 167 | "Usage: %s [OPTIONS] FILE\n" |
| 168 | "Virtual RAPL MSR helper program for QEMU\n" |
| 169 | "\n" |
| 170 | " -h, --help display this help and exit\n" |
| 171 | " -V, --version output version information and exit\n" |
| 172 | "\n" |
| 173 | " -d, --daemon run in the background\n" |
| 174 | " -f, --pidfile=PATH PID file when running as a daemon\n" |
| 175 | " (default '%s')\n" |
| 176 | " -k, --socket=PATH path to the unix socket\n" |
| 177 | " (default '%s')\n" |
| 178 | " -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" |
| 179 | " specify tracing options\n" |
| 180 | #ifdef CONFIG_LIBCAP_NG |
| 181 | " -u, --user=USER user to drop privileges to\n" |
| 182 | " -g, --group=GROUP group to drop privileges to\n" |
| 183 | #endif |
| 184 | "\n" |
| 185 | QEMU_HELP_BOTTOM "\n" |
| 186 | , name, pidfile, socket_path); |
| 187 | } |
| 188 | |
| 189 | static void version(const char *name) |
| 190 | { |
| 191 | printf( |
| 192 | "%s " QEMU_FULL_VERSION "\n" |
| 193 | "Written by Anthony Harivel.\n" |
| 194 | "\n" |
| 195 | QEMU_COPYRIGHT "\n" |
| 196 | "This is free software; see the source for copying conditions. There is NO\n" |
| 197 | "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n" |
| 198 | , name); |
| 199 | } |
| 200 | |
| 201 | typedef struct VMSRHelperClient { |
| 202 | QIOChannelSocket *ioc; |
| 203 | Coroutine *co; |
| 204 | } VMSRHelperClient; |
| 205 | |
| 206 | static void coroutine_fn vh_co_entry(void *opaque) |
| 207 | { |
| 208 | VMSRHelperClient *client = opaque; |
| 209 | Error *local_err = NULL; |
| 210 | unsigned int peer_pid; |
| 211 | uint32_t request[3]; |
| 212 | uint64_t vmsr; |
| 213 | int r; |
| 214 | |
| 215 | if (!qio_channel_set_blocking(QIO_CHANNEL(client->ioc), |
| 216 | false, &local_err)) { |
| 217 | goto out; |
| 218 | } |
| 219 | |
| 220 | qio_channel_set_follow_coroutine_ctx(QIO_CHANNEL(client->ioc), true); |
| 221 | |
| 222 | /* |
| 223 | * Check peer credentials |
| 224 | */ |
| 225 | r = qio_channel_get_peerpid(QIO_CHANNEL(client->ioc), |
| 226 | &peer_pid, |
| 227 | &local_err); |
| 228 | if (r < 0) { |
| 229 | goto out; |
| 230 | } |
| 231 | |
| 232 | for (;;) { |
| 233 | /* |
| 234 | * Read the requested MSR |
| 235 | * Only RAPL MSR in rapl-msr-index.h is allowed |
| 236 | */ |
| 237 | r = qio_channel_read_all_eof(QIO_CHANNEL(client->ioc), |
| 238 | (char *) &request, sizeof(request), &local_err); |
| 239 | if (r <= 0) { |
| 240 | break; |
| 241 | } |
| 242 | |
| 243 | if (!is_msr_allowed(request[0])) { |
| 244 | error_report("Requested unallowed msr: %d", request[0]); |
| 245 | break; |
| 246 | } |
| 247 | |
| 248 | vmsr = vmsr_read_msr(request[0], request[1]); |
| 249 | |
| 250 | if (!is_tid_present(peer_pid, request[2])) { |
| 251 | error_report("Requested TID not in peer PID: %d %d", |
| 252 | peer_pid, request[2]); |
| 253 | vmsr = 0; |
| 254 | } |
| 255 | |
| 256 | r = qio_channel_write_all(QIO_CHANNEL(client->ioc), |
| 257 | (char *) &vmsr, |
| 258 | sizeof(vmsr), |
| 259 | &local_err); |
| 260 | if (r < 0) { |
| 261 | break; |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | out: |
| 266 | if (local_err) { |
| 267 | if (!verbose) { |
| 268 | error_free(local_err); |
| 269 | } else { |
| 270 | error_report_err(local_err); |
| 271 | } |
| 272 | } |
| 273 | |
| 274 | object_unref(OBJECT(client->ioc)); |
| 275 | g_free(client); |
| 276 | } |
| 277 | |
| 278 | static gboolean accept_client(QIOChannel *ioc, |
| 279 | GIOCondition cond, |
| 280 | gpointer opaque) |
| 281 | { |
| 282 | QIOChannelSocket *cioc; |
| 283 | VMSRHelperClient *vmsrh; |
| 284 | |
| 285 | cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc), |
| 286 | NULL); |
| 287 | if (!cioc) { |
| 288 | return TRUE; |
| 289 | } |
| 290 | |
| 291 | vmsrh = g_new(VMSRHelperClient, 1); |
| 292 | vmsrh->ioc = cioc; |
| 293 | vmsrh->co = qemu_coroutine_create(vh_co_entry, vmsrh); |
| 294 | qemu_coroutine_enter(vmsrh->co); |
| 295 | |
| 296 | return TRUE; |
| 297 | } |
| 298 | |
| 299 | static void termsig_handler(int signum) |
| 300 | { |
| 301 | qatomic_cmpxchg(&state, RUNNING, TERMINATE); |
| 302 | qemu_notify_event(); |
| 303 | } |
| 304 | |
| 305 | static void close_server_socket(void) |
| 306 | { |
| 307 | assert(server_ioc); |
| 308 | |
| 309 | g_source_remove(server_watch); |
| 310 | server_watch = -1; |
| 311 | object_unref(OBJECT(server_ioc)); |
| 312 | num_active_sockets--; |
| 313 | } |
| 314 | |
| 315 | #ifdef CONFIG_LIBCAP_NG |
| 316 | static int drop_privileges(void) |
| 317 | { |
| 318 | /* clear all capabilities */ |
| 319 | capng_clear(CAPNG_SELECT_BOTH); |
| 320 | |
| 321 | if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED, |
| 322 | CAP_SYS_RAWIO) < 0) { |
| 323 | return -1; |
| 324 | } |
| 325 | |
| 326 | return 0; |
| 327 | } |
| 328 | #endif |
| 329 | |
| 330 | int main(int argc, char **argv) |
| 331 | { |
| 332 | const char *sopt = "hVk:f:dT:u:g:vq"; |
| 333 | struct option lopt[] = { |
| 334 | { "help", no_argument, NULL, 'h' }, |
| 335 | { "version", no_argument, NULL, 'V' }, |
| 336 | { "socket", required_argument, NULL, 'k' }, |
| 337 | { "pidfile", required_argument, NULL, 'f' }, |
| 338 | { "daemon", no_argument, NULL, 'd' }, |
| 339 | { "trace", required_argument, NULL, 'T' }, |
| 340 | { "verbose", no_argument, NULL, 'v' }, |
| 341 | { NULL, 0, NULL, 0 } |
| 342 | }; |
| 343 | int opt_ind = 0; |
| 344 | int ch; |
| 345 | Error *local_err = NULL; |
| 346 | bool daemonize = false; |
| 347 | bool pidfile_specified = false; |
| 348 | bool socket_path_specified = false; |
| 349 | unsigned socket_activation; |
| 350 | |
| 351 | struct sigaction sa_sigterm; |
| 352 | memset(&sa_sigterm, 0, sizeof(sa_sigterm)); |
| 353 | sa_sigterm.sa_handler = termsig_handler; |
| 354 | sigaction(SIGTERM, &sa_sigterm, NULL); |
| 355 | sigaction(SIGINT, &sa_sigterm, NULL); |
| 356 | sigaction(SIGHUP, &sa_sigterm, NULL); |
| 357 | |
| 358 | signal(SIGPIPE, SIG_IGN); |
| 359 | |
| 360 | error_init(argv[0]); |
| 361 | module_call_init(MODULE_INIT_TRACE); |
| 362 | module_call_init(MODULE_INIT_QOM); |
| 363 | qemu_add_opts(&qemu_trace_opts); |
| 364 | qemu_init_exec_dir(argv[0]); |
| 365 | |
| 366 | compute_default_paths(); |
| 367 | |
| 368 | /* |
| 369 | * Sanity check |
| 370 | * 1. cpu must be Intel cpu |
| 371 | * 2. RAPL must be enabled |
| 372 | */ |
| 373 | if (!is_intel_processor()) { |
| 374 | error_report("error: CPU is not INTEL cpu"); |
| 375 | exit(EXIT_FAILURE); |
| 376 | } |
| 377 | |
| 378 | if (!is_rapl_enabled()) { |
| 379 | error_report("error: RAPL driver not enable"); |
| 380 | exit(EXIT_FAILURE); |
| 381 | } |
| 382 | |
| 383 | while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { |
| 384 | switch (ch) { |
| 385 | case 'k': |
| 386 | g_free(socket_path); |
| 387 | socket_path = g_strdup(optarg); |
| 388 | socket_path_specified = true; |
| 389 | if (socket_path[0] != '/') { |
| 390 | error_report("socket path must be absolute"); |
| 391 | exit(EXIT_FAILURE); |
| 392 | } |
| 393 | break; |
| 394 | case 'f': |
| 395 | g_free(pidfile); |
| 396 | pidfile = g_strdup(optarg); |
| 397 | pidfile_specified = true; |
| 398 | break; |
| 399 | #ifdef CONFIG_LIBCAP_NG |
| 400 | case 'u': { |
| 401 | unsigned long res; |
| 402 | struct passwd *userinfo = getpwnam(optarg); |
| 403 | if (userinfo) { |
| 404 | uid = userinfo->pw_uid; |
| 405 | } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 && |
| 406 | (uid_t)res == res) { |
| 407 | uid = res; |
| 408 | } else { |
| 409 | error_report("invalid user '%s'", optarg); |
| 410 | exit(EXIT_FAILURE); |
| 411 | } |
| 412 | break; |
| 413 | } |
| 414 | case 'g': { |
| 415 | unsigned long res; |
| 416 | struct group *groupinfo = getgrnam(optarg); |
| 417 | if (groupinfo) { |
| 418 | gid = groupinfo->gr_gid; |
| 419 | } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 && |
| 420 | (gid_t)res == res) { |
| 421 | gid = res; |
| 422 | } else { |
| 423 | error_report("invalid group '%s'", optarg); |
| 424 | exit(EXIT_FAILURE); |
| 425 | } |
| 426 | break; |
| 427 | } |
| 428 | #else |
| 429 | case 'u': |
| 430 | case 'g': |
| 431 | error_report("-%c not supported by this %s", ch, argv[0]); |
| 432 | exit(1); |
| 433 | #endif |
| 434 | case 'd': |
| 435 | daemonize = true; |
| 436 | break; |
| 437 | case 'v': |
| 438 | verbose = true; |
| 439 | break; |
| 440 | case 'T': |
| 441 | trace_opt_parse(optarg); |
| 442 | break; |
| 443 | case 'V': |
| 444 | version(argv[0]); |
| 445 | exit(EXIT_SUCCESS); |
| 446 | break; |
| 447 | case 'h': |
| 448 | usage(argv[0]); |
| 449 | exit(EXIT_SUCCESS); |
| 450 | break; |
| 451 | case '?': |
| 452 | error_report("Try `%s --help' for more information.", argv[0]); |
| 453 | exit(EXIT_FAILURE); |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | if (!trace_init_backends()) { |
| 458 | exit(EXIT_FAILURE); |
| 459 | } |
| 460 | trace_init_file(); |
| 461 | qemu_set_log(LOG_TRACE, &error_fatal); |
| 462 | |
| 463 | socket_activation = check_socket_activation(); |
| 464 | if (socket_activation == 0) { |
| 465 | SocketAddress saddr; |
| 466 | saddr = (SocketAddress){ |
| 467 | .type = SOCKET_ADDRESS_TYPE_UNIX, |
| 468 | .u.q_unix.path = socket_path, |
| 469 | }; |
| 470 | server_ioc = qio_channel_socket_new(); |
| 471 | if (qio_channel_socket_listen_sync(server_ioc, &saddr, |
| 472 | 1, &local_err) < 0) { |
| 473 | object_unref(OBJECT(server_ioc)); |
| 474 | error_report_err(local_err); |
| 475 | return 1; |
| 476 | } |
| 477 | } else { |
| 478 | /* Using socket activation - check user didn't use -p etc. */ |
| 479 | if (socket_path_specified) { |
| 480 | error_report("Unix socket can't be set when" |
| 481 | "using socket activation"); |
| 482 | exit(EXIT_FAILURE); |
| 483 | } |
| 484 | |
| 485 | /* Can only listen on a single socket. */ |
| 486 | if (socket_activation > 1) { |
| 487 | error_report("%s does not support socket activation" |
| 488 | "with LISTEN_FDS > 1", |
| 489 | argv[0]); |
| 490 | exit(EXIT_FAILURE); |
| 491 | } |
| 492 | server_ioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD, |
| 493 | &local_err); |
| 494 | if (server_ioc == NULL) { |
| 495 | error_reportf_err(local_err, |
| 496 | "Failed to use socket activation: "); |
| 497 | exit(EXIT_FAILURE); |
| 498 | } |
| 499 | } |
| 500 | |
| 501 | qemu_init_main_loop(&error_fatal); |
| 502 | |
| 503 | server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc), |
| 504 | G_IO_IN, |
| 505 | accept_client, |
| 506 | NULL, NULL); |
| 507 | |
| 508 | if (daemonize) { |
| 509 | if (daemon(0, 0) < 0) { |
| 510 | error_report("Failed to daemonize: %s", strerror(errno)); |
| 511 | exit(EXIT_FAILURE); |
| 512 | } |
| 513 | } |
| 514 | |
| 515 | if (daemonize || pidfile_specified) { |
| 516 | qemu_write_pidfile(pidfile, &error_fatal); |
| 517 | } |
| 518 | |
| 519 | #ifdef CONFIG_LIBCAP_NG |
| 520 | if (drop_privileges() < 0) { |
| 521 | error_report("Failed to drop privileges: %s", strerror(errno)); |
| 522 | exit(EXIT_FAILURE); |
| 523 | } |
| 524 | #endif |
| 525 | |
| 526 | info_report("Listening on %s", socket_path); |
| 527 | |
| 528 | state = RUNNING; |
| 529 | do { |
| 530 | main_loop_wait(false); |
| 531 | if (state == TERMINATE) { |
| 532 | state = TERMINATING; |
| 533 | close_server_socket(); |
| 534 | } |
| 535 | } while (num_active_sockets > 0); |
| 536 | |
| 537 | exit(EXIT_SUCCESS); |
| 538 | } |