1 /* $NetBSD: xenbus_probe.c,v 1.27 2009/01/09 22:26:25 jym Exp $ */ 2 /****************************************************************************** 3 * Talks to Xen Store to figure out what devices we have. 4 * 5 * Copyright (C) 2005 Rusty Russell, IBM Corporation 6 * Copyright (C) 2005 Mike Wray, Hewlett-Packard 7 * Copyright (C) 2005 XenSource Ltd 8 * 9 * This file may be distributed separately from the Linux kernel, or 10 * incorporated into other software packages, subject to the following license: 11 * 12 * Permission is hereby granted, free of charge, to any person obtaining a copy 13 * of this source file (the "Software"), to deal in the Software without 14 * restriction, including without limitation the rights to use, copy, modify, 15 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 16 * and to permit persons to whom the Software is furnished to do so, subject to 17 * the following conditions: 18 * 19 * The above copyright notice and this permission notice shall be included in 20 * all copies or substantial portions of the Software. 21 * 22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 28 * IN THE SOFTWARE. 29 */ 30 31 #include <sys/cdefs.h> 32 __KERNEL_RCSID(0, "$NetBSD: xenbus_probe.c,v 1.27 2009/01/09 22:26:25 jym Exp $"); 33 34 #if 0 35 #define DPRINTK(fmt, args...) \ 36 printf("xenbus_probe (%s:%d) " fmt ".\n", __func__, __LINE__, ##args) 37 #else 38 #define DPRINTK(fmt, args...) ((void)0) 39 #endif 40 41 #include <sys/types.h> 42 #include <sys/null.h> 43 #include <sys/errno.h> 44 #include <sys/malloc.h> 45 #include <sys/systm.h> 46 #include <sys/param.h> 47 #include <sys/kthread.h> 48 #include <uvm/uvm.h> 49 50 #include <machine/stdarg.h> 51 52 #include <xen/xen.h> /* for xendomain_is_dom0() */ 53 #include <xen/hypervisor.h> 54 #include <xen/xenbus.h> 55 #include <xen/evtchn.h> 56 #include <xen/shutdown_xenbus.h> 57 58 #include "xenbus_comms.h" 59 60 extern struct semaphore xenwatch_mutex; 61 62 #define streq(a, b) (strcmp((a), (b)) == 0) 63 64 static int xenbus_match(device_t, cfdata_t, void *); 65 static void xenbus_attach(device_t, device_t, void *); 66 static int xenbus_print(void *, const char *); 67 68 static void xenbus_probe_init(void *); 69 70 static struct xenbus_device *xenbus_lookup_device_path(const char *); 71 72 CFATTACH_DECL_NEW(xenbus, 0, xenbus_match, xenbus_attach, 73 NULL, NULL); 74 75 device_t xenbus_dev; 76 77 SLIST_HEAD(, xenbus_device) xenbus_device_list; 78 SLIST_HEAD(, xenbus_backend_driver) xenbus_backend_driver_list = 79 SLIST_HEAD_INITIALIZER(xenbus_backend_driver); 80 81 int 82 xenbus_match(device_t parent, cfdata_t match, void *aux) 83 { 84 struct xenbus_attach_args *xa = (struct xenbus_attach_args *)aux; 85 86 if (strcmp(xa->xa_device, "xenbus") == 0) 87 return 1; 88 return 0; 89 } 90 91 static void 92 xenbus_attach(device_t parent, device_t self, void *aux) 93 { 94 int err; 95 96 aprint_normal(": Xen Virtual Bus Interface\n"); 97 xenbus_dev = self; 98 config_pending_incr(); 99 100 err = kthread_create(PRI_NONE, 0, NULL, xenbus_probe_init, NULL, 101 NULL, "xenbus_probe"); 102 if (err) 103 aprint_error_dev(xenbus_dev, 104 "kthread_create(xenbus_probe): %d\n", err); 105 } 106 107 void 108 xenbus_backend_register(struct xenbus_backend_driver *xbakd) 109 { 110 SLIST_INSERT_HEAD(&xenbus_backend_driver_list, xbakd, xbakd_entries); 111 } 112 113 static int 114 read_otherend_details(struct xenbus_device *xendev, 115 const char *id_node, const char *path_node) 116 { 117 int err; 118 char *val, *ep; 119 120 err = xenbus_read(NULL, xendev->xbusd_path, id_node, NULL, &val); 121 if (err) { 122 printf("reading other end details %s from %s\n", 123 id_node, xendev->xbusd_path); 124 xenbus_dev_fatal(xendev, err, 125 "reading other end details %s from %s", 126 id_node, xendev->xbusd_path); 127 return err; 128 } 129 xendev->xbusd_otherend_id = strtoul(val, &ep, 10); 130 if (val[0] == '\0' || *ep != '\0') { 131 printf("reading other end details %s from %s: %s is not a number\n", id_node, xendev->xbusd_path, val); 132 xenbus_dev_fatal(xendev, err, 133 "reading other end details %s from %s: %s is not a number", 134 id_node, xendev->xbusd_path, val); 135 free(val, M_DEVBUF); 136 return EFTYPE; 137 } 138 free(val, M_DEVBUF); 139 err = xenbus_read(NULL, xendev->xbusd_path, path_node, NULL, &val); 140 if (err) { 141 printf("reading other end details %s from %s (%d)\n", 142 path_node, xendev->xbusd_path, err); 143 xenbus_dev_fatal(xendev, err, 144 "reading other end details %s from %s", 145 path_node, xendev->xbusd_path); 146 return err; 147 } 148 DPRINTK("read_otherend_details: read %s/%s returned %s\n", 149 xendev->xbusd_path, path_node, val); 150 xendev->xbusd_otherend = val; 151 152 if (strlen(xendev->xbusd_otherend) == 0 || 153 !xenbus_exists(NULL, xendev->xbusd_otherend, "")) { 154 printf("missing other end from %s\n", xendev->xbusd_path); 155 xenbus_dev_fatal(xendev, -ENOENT, "missing other end from %s", 156 xendev->xbusd_path); 157 free(xendev->xbusd_otherend, M_DEVBUF); 158 xendev->xbusd_otherend = NULL; 159 return ENOENT; 160 } 161 162 return 0; 163 } 164 165 static int 166 read_backend_details(struct xenbus_device *xendev) 167 { 168 return read_otherend_details(xendev, "backend-id", "backend"); 169 } 170 171 172 static int 173 read_frontend_details(struct xenbus_device *xendev) 174 { 175 return read_otherend_details(xendev, "frontend-id", "frontend"); 176 } 177 178 #if unused 179 static void 180 free_otherend_details(struct xenbus_device *dev) 181 { 182 free(dev->xbusd_otherend, M_DEVBUF); 183 dev->xbusd_otherend = NULL; 184 } 185 #endif 186 187 188 static void 189 free_otherend_watch(struct xenbus_device *dev) 190 { 191 if (dev->xbusd_otherend_watch.node) { 192 unregister_xenbus_watch(&dev->xbusd_otherend_watch); 193 free(dev->xbusd_otherend_watch.node, M_DEVBUF); 194 dev->xbusd_otherend_watch.node = NULL; 195 } 196 } 197 198 static void 199 otherend_changed(struct xenbus_watch *watch, 200 const char **vec, unsigned int len) 201 { 202 struct xenbus_device *xdev = watch->xbw_dev; 203 XenbusState state; 204 205 /* Protect us against watches firing on old details when the otherend 206 details change, say immediately after a resume. */ 207 if (!xdev->xbusd_otherend || 208 strncmp(xdev->xbusd_otherend, vec[XS_WATCH_PATH], 209 strlen(xdev->xbusd_otherend))) { 210 DPRINTK("Ignoring watch at %s", vec[XS_WATCH_PATH]); 211 return; 212 } 213 214 state = xenbus_read_driver_state(xdev->xbusd_otherend); 215 216 DPRINTK("state is %d, %s, %s", 217 state, xdev->xbusd_otherend_watch.node, vec[XS_WATCH_PATH]); 218 if (state == XenbusStateClosed) { 219 int error; 220 if (xdev->xbusd_type == XENBUS_BACKEND_DEVICE) { 221 error = xdev->xbusd_u.b.b_detach( 222 xdev->xbusd_u.b.b_cookie); 223 if (error) { 224 printf("could not detach %s: %d\n", 225 xdev->xbusd_path, error); 226 return; 227 } 228 } else { 229 error = config_detach(xdev->xbusd_u.f.f_dev, 230 DETACH_FORCE); 231 if (error) { 232 printf("could not detach %s: %d\n", 233 device_xname(xdev->xbusd_u.f.f_dev), error); 234 return; 235 } 236 } 237 xenbus_free_device(xdev); 238 return; 239 } 240 if (xdev->xbusd_otherend_changed) 241 xdev->xbusd_otherend_changed( 242 (xdev->xbusd_type == XENBUS_BACKEND_DEVICE) ? 243 xdev->xbusd_u.b.b_cookie : xdev->xbusd_u.f.f_dev, state); 244 } 245 246 static int 247 talk_to_otherend(struct xenbus_device *dev) 248 { 249 free_otherend_watch(dev); 250 251 return xenbus_watch_path2(dev, dev->xbusd_otherend, "state", 252 &dev->xbusd_otherend_watch, 253 otherend_changed); 254 } 255 256 static struct xenbus_device * 257 xenbus_lookup_device_path(const char *path) 258 { 259 struct xenbus_device *xbusd; 260 261 SLIST_FOREACH(xbusd, &xenbus_device_list, xbusd_entries) { 262 if (strcmp(xbusd->xbusd_path, path) == 0) 263 return xbusd; 264 } 265 return NULL; 266 } 267 268 static int 269 xenbus_probe_device_type(const char *path, const char *type, 270 int (*create)(struct xenbus_device *)) 271 { 272 int err, i, msize; 273 unsigned long state; 274 char **dir; 275 unsigned int dir_n = 0; 276 struct xenbus_device *xbusd; 277 struct xenbusdev_attach_args xa; 278 char *ep; 279 280 DPRINTK("probe %s type %s", path, type); 281 err = xenbus_directory(NULL, path, "", &dir_n, &dir); 282 DPRINTK("directory err %d dir_n %d", err, dir_n); 283 if (err) 284 return err; 285 286 for (i = 0; i < dir_n; i++) { 287 /* 288 * add size of path to size of xenbus_device. xenbus_device 289 * already has room for one char in xbusd_path. 290 */ 291 msize = sizeof(*xbusd) + strlen(path) + strlen(dir[i]) + 2; 292 xbusd = malloc(msize, M_DEVBUF, M_WAITOK | M_ZERO); 293 if (xbusd == NULL) 294 panic("can't malloc xbusd"); 295 296 snprintf(__UNCONST(xbusd->xbusd_path), 297 msize - sizeof(*xbusd) + 1, "%s/%s", path, dir[i]); 298 if (xenbus_lookup_device_path(xbusd->xbusd_path) != NULL) { 299 /* device already registered */ 300 free(xbusd, M_DEVBUF); 301 continue; 302 } 303 err = xenbus_read_ul(NULL, xbusd->xbusd_path, "state", 304 &state, 10); 305 if (err) { 306 printf("xenbus: can't get state " 307 "for %s (%d)\n", xbusd->xbusd_path, err); 308 free(xbusd, M_DEVBUF); 309 continue; 310 } 311 if (state != XenbusStateInitialising) { 312 /* device is not new */ 313 free(xbusd, M_DEVBUF); 314 continue; 315 } 316 317 xbusd->xbusd_otherend_watch.xbw_dev = xbusd; 318 DPRINTK("xenbus_probe_device_type probe %s\n", 319 xbusd->xbusd_path); 320 if (create != NULL) { 321 xbusd->xbusd_type = XENBUS_BACKEND_DEVICE; 322 err = read_frontend_details(xbusd); 323 if (err != 0) { 324 printf("xenbus: can't get frontend details " 325 "for %s (%d)\n", xbusd->xbusd_path, err); 326 break; 327 } 328 if (create(xbusd)) { 329 free(xbusd, M_DEVBUF); 330 continue; 331 } 332 } else { 333 xbusd->xbusd_type = XENBUS_FRONTEND_DEVICE; 334 xa.xa_xbusd = xbusd; 335 xa.xa_type = type; 336 xa.xa_id = strtoul(dir[i], &ep, 0); 337 if (dir[i][0] == '\0' || *ep != '\0') { 338 printf("xenbus device type %s: id %s is not a" 339 " number\n", type, dir[i]); 340 err = EFTYPE; 341 free(xbusd, M_DEVBUF); 342 break; 343 } 344 err = read_backend_details(xbusd); 345 if (err != 0) { 346 printf("xenbus: can't get backend details " 347 "for %s (%d)\n", xbusd->xbusd_path, err); 348 break; 349 } 350 xbusd->xbusd_u.f.f_dev = config_found_ia(xenbus_dev, 351 "xenbus", &xa, xenbus_print); 352 if (xbusd->xbusd_u.f.f_dev == NULL) { 353 free(xbusd, M_DEVBUF); 354 continue; 355 } 356 } 357 SLIST_INSERT_HEAD(&xenbus_device_list, 358 xbusd, xbusd_entries); 359 talk_to_otherend(xbusd); 360 } 361 free(dir, M_DEVBUF); 362 return err; 363 } 364 365 static int 366 xenbus_print(void *aux, const char *pnp) 367 { 368 struct xenbusdev_attach_args *xa = aux; 369 370 if (pnp) { 371 if (strcmp(xa->xa_type, "vbd") == 0) 372 aprint_normal("xbd"); 373 else if (strcmp(xa->xa_type, "vif") == 0) 374 aprint_normal("xennet"); 375 else 376 aprint_normal("unknown type %s", xa->xa_type); 377 aprint_normal(" at %s", pnp); 378 } 379 aprint_normal(" id %d", xa->xa_id); 380 return(UNCONF); 381 } 382 383 static int 384 xenbus_probe_frontends(void) 385 { 386 int err; 387 char **dir; 388 unsigned int i, dir_n; 389 char path[30]; 390 391 DPRINTK("probe device"); 392 err = xenbus_directory(NULL, "device", "", &dir_n, &dir); 393 DPRINTK("directory err %d dir_n %d", err, dir_n); 394 if (err) 395 return err; 396 397 for (i = 0; i < dir_n; i++) { 398 /* 399 * console is configured through xen_start_info when 400 * xencons is attaching to hypervisor, so avoid console 401 * probing when configuring xenbus devices 402 */ 403 if (strcmp(dir[i], "console") == 0) 404 continue; 405 406 snprintf(path, sizeof(path), "device/%s", dir[i]); 407 err = xenbus_probe_device_type(path, dir[i], NULL); 408 if (err) 409 break; 410 } 411 free(dir, M_DEVBUF); 412 return err; 413 } 414 415 static int 416 xenbus_probe_backends(void) 417 { 418 int err; 419 char **dirt, **dirid; 420 unsigned int type, id, dirt_n, dirid_n; 421 char path[30]; 422 struct xenbus_backend_driver *xbakd; 423 424 DPRINTK("probe backend"); 425 err = xenbus_directory(NULL, "backend", "", &dirt_n, &dirt); 426 DPRINTK("directory err %d dirt_n %d", err, dirt_n); 427 if (err) 428 return err; 429 430 for (type = 0; type < dirt_n; type++) { 431 SLIST_FOREACH(xbakd, &xenbus_backend_driver_list, 432 xbakd_entries) { 433 if (strcmp(dirt[type], xbakd->xbakd_type) == 0) 434 break; 435 } 436 if (xbakd == NULL) 437 continue; 438 err = xenbus_directory(NULL, "backend", dirt[type], 439 &dirid_n, &dirid); 440 DPRINTK("directory backend/%s err %d dirid_n %d", 441 dirt[type], err, dirid_n); 442 if (err) { 443 free(dirt, M_DEVBUF); /* to be checked */ 444 return err; 445 } 446 for (id = 0; id < dirid_n; id++) { 447 snprintf(path, sizeof(path), "backend/%s/%s", 448 dirt[type], dirid[id]); 449 err = xenbus_probe_device_type(path, dirt[type], 450 xbakd->xbakd_create); 451 if (err) 452 break; 453 } 454 free(dirid, M_DEVBUF); 455 } 456 free(dirt, M_DEVBUF); 457 return err; 458 } 459 460 int 461 xenbus_free_device(struct xenbus_device *xbusd) 462 { 463 KASSERT(xenbus_lookup_device_path(xbusd->xbusd_path) == xbusd); 464 SLIST_REMOVE(&xenbus_device_list, xbusd, xenbus_device, xbusd_entries); 465 free_otherend_watch(xbusd); 466 free(xbusd->xbusd_otherend, M_DEVBUF); 467 xenbus_switch_state(xbusd, NULL, XenbusStateClosed); 468 free(xbusd, M_DEVBUF); 469 return 0; 470 } 471 472 static void 473 frontend_changed(struct xenbus_watch *watch, 474 const char **vec, unsigned int len) 475 { 476 DPRINTK("frontend_changed %s\n", vec[XS_WATCH_PATH]); 477 xenbus_probe_frontends(); 478 } 479 480 static void 481 backend_changed(struct xenbus_watch *watch, 482 const char **vec, unsigned int len) 483 { 484 DPRINTK("backend_changed %s\n", vec[XS_WATCH_PATH]); 485 xenbus_probe_backends(); 486 } 487 488 489 /* We watch for devices appearing and vanishing. */ 490 static struct xenbus_watch fe_watch; 491 492 static struct xenbus_watch be_watch; 493 494 /* A flag to determine if xenstored is 'ready' (i.e. has started) */ 495 int xenstored_ready = 0; 496 497 void 498 xenbus_probe(void *unused) 499 { 500 KASSERT((xenstored_ready > 0)); 501 502 /* Enumerate devices in xenstore. */ 503 xenbus_probe_frontends(); 504 xenbus_probe_backends(); 505 506 /* Watch for changes. */ 507 fe_watch.node = malloc(strlen("device" + 1), M_DEVBUF, M_NOWAIT); 508 strcpy(fe_watch.node, "device"); 509 fe_watch.xbw_callback = frontend_changed; 510 register_xenbus_watch(&fe_watch); 511 be_watch.node = malloc(strlen("backend" + 1), M_DEVBUF, M_NOWAIT); 512 strcpy(be_watch.node, "backend"); 513 be_watch.xbw_callback = backend_changed; 514 register_xenbus_watch(&be_watch); 515 shutdown_xenbus_setup(); 516 517 /* Notify others that xenstore is up */ 518 //notifier_call_chain(&xenstore_chain, 0, NULL); 519 } 520 521 static void 522 xenbus_probe_init(void *unused) 523 { 524 int err = 0; 525 bool dom0; 526 vaddr_t page = 0; 527 528 DPRINTK(""); 529 530 SLIST_INIT(&xenbus_device_list); 531 532 /* 533 ** Domain0 doesn't have a store_evtchn or store_mfn yet. 534 */ 535 dom0 = xendomain_is_dom0(); 536 if (dom0) { 537 #if defined(DOM0OPS) 538 paddr_t ma; 539 evtchn_op_t op = { .cmd = 0 }; 540 541 /* Allocate page. */ 542 page = uvm_km_alloc(kernel_map, PAGE_SIZE, 0, 543 UVM_KMF_ZERO | UVM_KMF_WIRED); 544 if (!page) 545 panic("can't get xenstore page"); 546 547 (void)pmap_extract_ma(pmap_kernel(), page, &ma); 548 xen_start_info.store_mfn = ma >> PAGE_SHIFT; 549 xenstore_interface = (void *)page; 550 551 /* Next allocate a local port which xenstored can bind to */ 552 op.cmd = EVTCHNOP_alloc_unbound; 553 op.u.alloc_unbound.dom = DOMID_SELF; 554 op.u.alloc_unbound.remote_dom = 0; 555 556 err = HYPERVISOR_event_channel_op(&op); 557 if (err) { 558 aprint_error_dev(xenbus_dev, 559 "can't register xenstore event\n"); 560 goto err0; 561 } 562 563 xen_start_info.store_evtchn = op.u.alloc_unbound.port; 564 565 /* And finally publish the above info in /kern/xen */ 566 xenbus_kernfs_init(); 567 568 DELAY(1000); 569 #else /* DOM0OPS */ 570 kthread_exit(0); /* can't get a working xenstore in this case */ 571 #endif /* DOM0OPS */ 572 } 573 574 /* register event handler */ 575 xb_init_comms(xenbus_dev); 576 577 /* Initialize the interface to xenstore. */ 578 err = xs_init(xenbus_dev); 579 if (err) { 580 aprint_error_dev(xenbus_dev, 581 "Error initializing xenstore comms: %i\n", err); 582 goto err0; 583 } 584 585 if (!dom0) { 586 xenstored_ready = 1; 587 xenbus_probe(NULL); 588 } 589 590 DPRINTK("done"); 591 config_pending_decr(); 592 #ifdef DOM0OPS 593 if (dom0) { 594 int s; 595 s = spltty(); 596 while (xenstored_ready == 0) { 597 tsleep(&xenstored_ready, PRIBIO, "xsready", 0); 598 xenbus_probe(NULL); 599 } 600 splx(s); 601 } 602 #endif 603 kthread_exit(0); 604 605 err0: 606 if (page) 607 uvm_km_free(kernel_map, page, PAGE_SIZE, 608 UVM_KMF_ZERO | UVM_KMF_WIRED); 609 kthread_exit(err); 610 } 611 612 /* 613 * Local variables: 614 * c-file-style: "linux" 615 * indent-tabs-mode: t 616 * c-indent-level: 8 617 * c-basic-offset: 8 618 * tab-width: 8 619 * End: 620 */ 621