hw/xen/xen_backend.c

   1 /*
   2  *  xen backend driver infrastructure
   3  *  (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; under version 2 of the License.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License along
  15  *  with this program; if not, see <http://www.gnu.org/licenses/>.
  16  *
  17  *  Contributions after 2012-01-13 are licensed under the terms of the
  18  *  GNU GPL, version 2 or (at your option) any later version.
  19  */
  20
  21 /*
  22  * TODO: add some xenbus / xenstore concepts overview here.
  23  */
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <stdarg.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30 #include <fcntl.h>
  31 #include <inttypes.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <sys/mman.h>
  35 #include <sys/signal.h>
  36
  37 #include "hw/hw.h"
  38 #include "sysemu/char.h"
  39 #include "qemu/log.h"
  40 #include "hw/xen/xen_backend.h"
  41
  42 #include <xen/grant_table.h>
  43
  44 /* ------------------------------------------------------------- */
  45
  46 /* public */
  47 XenXC xen_xc = XC_HANDLER_INITIAL_VALUE;
  48 struct xs_handle *xenstore = NULL;
  49 const char *xen_protocol;
  50
  51 /* private */
  52 static QTAILQ_HEAD(XenDeviceHead, XenDevice) xendevs = QTAILQ_HEAD_INITIALIZER(xendevs);
  53 static int debug = 0;
  54
  55 /* ------------------------------------------------------------- */
  56
  57 int xenstore_write_str(const char *base, const char *node, const char *val)
  58 {
  59     char abspath[XEN_BUFSIZE];
  60
  61     snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
  62     if (!xs_write(xenstore, 0, abspath, val, strlen(val))) {
  63         return -1;
  64     }
  65     return 0;
  66 }
  67
  68 char *xenstore_read_str(const char *base, const char *node)
  69 {
  70     char abspath[XEN_BUFSIZE];
  71     unsigned int len;
  72     char *str, *ret = NULL;
  73
  74     snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
  75     str = xs_read(xenstore, 0, abspath, &len);
  76     if (str != NULL) {
  77         /* move to qemu-allocated memory to make sure
  78          * callers can savely g_free() stuff. */
  79         ret = g_strdup(str);
  80         free(str);
  81     }
  82     return ret;
  83 }
  84
  85 int xenstore_write_int(const char *base, const char *node, int ival)
  86 {
  87     char val[12];
  88
  89     snprintf(val, sizeof(val), "%d", ival);
  90     return xenstore_write_str(base, node, val);
  91 }
  92
  93 int xenstore_write_int64(const char *base, const char *node, int64_t ival)
  94 {
  95     char val[21];
  96
  97     snprintf(val, sizeof(val), "%"PRId64, ival);
  98     return xenstore_write_str(base, node, val);
  99 }
 100
 101 int xenstore_read_int(const char *base, const char *node, int *ival)
 102 {
 103     char *val;
 104     int rc = -1;
 105
 106     val = xenstore_read_str(base, node);
 107     if (val && 1 == sscanf(val, "%d", ival)) {
 108         rc = 0;
 109     }
 110     g_free(val);
 111     return rc;
 112 }
 113
 114 int xenstore_read_uint64(const char *base, const char *node, uint64_t *uval)
 115 {
 116     char *val;
 117     int rc = -1;
 118
 119     val = xenstore_read_str(base, node);
 120     if (val && 1 == sscanf(val, "%"SCNu64, uval)) {
 121         rc = 0;
 122     }
 123     g_free(val);
 124     return rc;
 125 }
 126
 127 int xenstore_write_be_str(struct XenDevice *xendev, const char *node, const char *val)
 128 {
 129     return xenstore_write_str(xendev->be, node, val);
 130 }
 131
 132 int xenstore_write_be_int(struct XenDevice *xendev, const char *node, int ival)
 133 {
 134     return xenstore_write_int(xendev->be, node, ival);
 135 }
 136
 137 int xenstore_write_be_int64(struct XenDevice *xendev, const char *node, int64_t ival)
 138 {
 139     return xenstore_write_int64(xendev->be, node, ival);
 140 }
 141
 142 char *xenstore_read_be_str(struct XenDevice *xendev, const char *node)
 143 {
 144     return xenstore_read_str(xendev->be, node);
 145 }
 146
 147 int xenstore_read_be_int(struct XenDevice *xendev, const char *node, int *ival)
 148 {
 149     return xenstore_read_int(xendev->be, node, ival);
 150 }
 151
 152 char *xenstore_read_fe_str(struct XenDevice *xendev, const char *node)
 153 {
 154     return xenstore_read_str(xendev->fe, node);
 155 }
 156
 157 int xenstore_read_fe_int(struct XenDevice *xendev, const char *node, int *ival)
 158 {
 159     return xenstore_read_int(xendev->fe, node, ival);
 160 }
 161
 162 int xenstore_read_fe_uint64(struct XenDevice *xendev, const char *node, uint64_t *uval)
 163 {
 164     return xenstore_read_uint64(xendev->fe, node, uval);
 165 }
 166
 167 /* ------------------------------------------------------------- */
 168
 169 const char *xenbus_strstate(enum xenbus_state state)
 170 {
 171     static const char *const name[] = {
 172         [ XenbusStateUnknown      ] = "Unknown",
 173         [ XenbusStateInitialising ] = "Initialising",
 174         [ XenbusStateInitWait     ] = "InitWait",
 175         [ XenbusStateInitialised  ] = "Initialised",
 176         [ XenbusStateConnected    ] = "Connected",
 177         [ XenbusStateClosing      ] = "Closing",
 178         [ XenbusStateClosed       ] = "Closed",
 179     };
 180     return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
 181 }
 182
 183 int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state)
 184 {
 185     int rc;
 186
 187     rc = xenstore_write_be_int(xendev, "state", state);
 188     if (rc < 0) {
 189         return rc;
 190     }
 191     xen_be_printf(xendev, 1, "backend state: %s -> %s\n",
 192                   xenbus_strstate(xendev->be_state), xenbus_strstate(state));
 193     xendev->be_state = state;
 194     return 0;
 195 }
 196
 197 /* ------------------------------------------------------------- */
 198
 199 struct XenDevice *xen_be_find_xendev(const char *type, int dom, int dev)
 200 {
 201     struct XenDevice *xendev;
 202
 203     QTAILQ_FOREACH(xendev, &xendevs, next) {
 204         if (xendev->dom != dom) {
 205             continue;
 206         }
 207         if (xendev->dev != dev) {
 208             continue;
 209         }
 210         if (strcmp(xendev->type, type) != 0) {
 211             continue;
 212         }
 213         return xendev;
 214     }
 215     return NULL;
 216 }
 217
 218 /*
 219  * get xen backend device, allocate a new one if it doesn't exist.
 220  */
 221 static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
 222                                            struct XenDevOps *ops)
 223 {
 224     struct XenDevice *xendev;
 225
 226     xendev = xen_be_find_xendev(type, dom, dev);
 227     if (xendev) {
 228         return xendev;
 229     }
 230
 231     /* init new xendev */
 232     xendev = g_malloc0(ops->size);
 233     xendev->type  = type;
 234     xendev->dom   = dom;
 235     xendev->dev   = dev;
 236     xendev->ops   = ops;
 237
 238     snprintf(xendev->be, sizeof(xendev->be), "backend/%s/%d/%d",
 239              xendev->type, xendev->dom, xendev->dev);
 240     snprintf(xendev->name, sizeof(xendev->name), "%s-%d",
 241              xendev->type, xendev->dev);
 242
 243     xendev->debug      = debug;
 244     xendev->local_port = -1;
 245
 246     xendev->evtchndev = xen_xc_evtchn_open(NULL, 0);
 247     if (xendev->evtchndev == XC_HANDLER_INITIAL_VALUE) {
 248         xen_be_printf(NULL, 0, "can't open evtchn device\n");
 249         g_free(xendev);
 250         return NULL;
 251     }
 252     fcntl(xc_evtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC);
 253
 254     if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
 255         xendev->gnttabdev = xen_xc_gnttab_open(NULL, 0);
 256         if (xendev->gnttabdev == XC_HANDLER_INITIAL_VALUE) {
 257             xen_be_printf(NULL, 0, "can't open gnttab device\n");
 258             xc_evtchn_close(xendev->evtchndev);
 259             g_free(xendev);
 260             return NULL;
 261         }
 262     } else {
 263         xendev->gnttabdev = XC_HANDLER_INITIAL_VALUE;
 264     }
 265
 266     QTAILQ_INSERT_TAIL(&xendevs, xendev, next);
 267
 268     if (xendev->ops->alloc) {
 269         xendev->ops->alloc(xendev);
 270     }
 271
 272     return xendev;
 273 }
 274
 275 /*
 276  * release xen backend device.
 277  */
 278 static struct XenDevice *xen_be_del_xendev(int dom, int dev)
 279 {
 280     struct XenDevice *xendev, *xnext;
 281
 282     /*
 283      * This is pretty much like QTAILQ_FOREACH(xendev, &xendevs, next) but
 284      * we save the next pointer in xnext because we might free xendev.
 285      */
 286     xnext = xendevs.tqh_first;
 287     while (xnext) {
 288         xendev = xnext;
 289         xnext = xendev->next.tqe_next;
 290
 291         if (xendev->dom != dom) {
 292             continue;
 293         }
 294         if (xendev->dev != dev && dev != -1) {
 295             continue;
 296         }
 297
 298         if (xendev->ops->free) {
 299             xendev->ops->free(xendev);
 300         }
 301
 302         if (xendev->fe) {
 303             char token[XEN_BUFSIZE];
 304             snprintf(token, sizeof(token), "fe:%p", xendev);
 305             xs_unwatch(xenstore, xendev->fe, token);
 306             g_free(xendev->fe);
 307         }
 308
 309         if (xendev->evtchndev != XC_HANDLER_INITIAL_VALUE) {
 310             xc_evtchn_close(xendev->evtchndev);
 311         }
 312         if (xendev->gnttabdev != XC_HANDLER_INITIAL_VALUE) {
 313             xc_gnttab_close(xendev->gnttabdev);
 314         }
 315
 316         QTAILQ_REMOVE(&xendevs, xendev, next);
 317         g_free(xendev);
 318     }
 319     return NULL;
 320 }
 321
 322 /*
 323  * Sync internal data structures on xenstore updates.
 324  * Node specifies the changed field.  node = NULL means
 325  * update all fields (used for initialization).
 326  */
 327 static void xen_be_backend_changed(struct XenDevice *xendev, const char *node)
 328 {
 329     if (node == NULL  ||  strcmp(node, "online") == 0) {
 330         if (xenstore_read_be_int(xendev, "online", &xendev->online) == -1) {
 331             xendev->online = 0;
 332         }
 333     }
 334
 335     if (node) {
 336         xen_be_printf(xendev, 2, "backend update: %s\n", node);
 337         if (xendev->ops->backend_changed) {
 338             xendev->ops->backend_changed(xendev, node);
 339         }
 340     }
 341 }
 342
 343 static void xen_be_frontend_changed(struct XenDevice *xendev, const char *node)
 344 {
 345     int fe_state;
 346
 347     if (node == NULL  ||  strcmp(node, "state") == 0) {
 348         if (xenstore_read_fe_int(xendev, "state", &fe_state) == -1) {
 349             fe_state = XenbusStateUnknown;
 350         }
 351         if (xendev->fe_state != fe_state) {
 352             xen_be_printf(xendev, 1, "frontend state: %s -> %s\n",
 353                           xenbus_strstate(xendev->fe_state),
 354                           xenbus_strstate(fe_state));
 355         }
 356         xendev->fe_state = fe_state;
 357     }
 358     if (node == NULL  ||  strcmp(node, "protocol") == 0) {
 359         g_free(xendev->protocol);
 360         xendev->protocol = xenstore_read_fe_str(xendev, "protocol");
 361         if (xendev->protocol) {
 362             xen_be_printf(xendev, 1, "frontend protocol: %s\n", xendev->protocol);
 363         }
 364     }
 365
 366     if (node) {
 367         xen_be_printf(xendev, 2, "frontend update: %s\n", node);
 368         if (xendev->ops->frontend_changed) {
 369             xendev->ops->frontend_changed(xendev, node);
 370         }
 371     }
 372 }
 373
 374 /* ------------------------------------------------------------- */
 375 /* Check for possible state transitions and perform them.        */
 376
 377 /*
 378  * Initial xendev setup.  Read frontend path, register watch for it.
 379  * Should succeed once xend finished setting up the backend device.
 380  *
 381  * Also sets initial state (-> Initializing) when done.  Which
 382  * only affects the xendev->be_state variable as xenbus should
 383  * already be put into that state by xend.
 384  */
 385 static int xen_be_try_setup(struct XenDevice *xendev)
 386 {
 387     char token[XEN_BUFSIZE];
 388     int be_state;
 389
 390     if (xenstore_read_be_int(xendev, "state", &be_state) == -1) {
 391         xen_be_printf(xendev, 0, "reading backend state failed\n");
 392         return -1;
 393     }
 394
 395     if (be_state != XenbusStateInitialising) {
 396         xen_be_printf(xendev, 0, "initial backend state is wrong (%s)\n",
 397                       xenbus_strstate(be_state));
 398         return -1;
 399     }
 400
 401     xendev->fe = xenstore_read_be_str(xendev, "frontend");
 402     if (xendev->fe == NULL) {
 403         xen_be_printf(xendev, 0, "reading frontend path failed\n");
 404         return -1;
 405     }
 406
 407     /* setup frontend watch */
 408     snprintf(token, sizeof(token), "fe:%p", xendev);
 409     if (!xs_watch(xenstore, xendev->fe, token)) {
 410         xen_be_printf(xendev, 0, "watching frontend path (%s) failed\n",
 411                       xendev->fe);
 412         return -1;
 413     }
 414     xen_be_set_state(xendev, XenbusStateInitialising);
 415
 416     xen_be_backend_changed(xendev, NULL);
 417     xen_be_frontend_changed(xendev, NULL);
 418     return 0;
 419 }
 420
 421 /*
 422  * Try initialize xendev.  Prepare everything the backend can do
 423  * without synchronizing with the frontend.  Fakes hotplug-status.  No
 424  * hotplug involved here because this is about userspace drivers, thus
 425  * there are kernel backend devices which could invoke hotplug.
 426  *
 427  * Goes to InitWait on success.
 428  */
 429 static int xen_be_try_init(struct XenDevice *xendev)
 430 {
 431     int rc = 0;
 432
 433     if (!xendev->online) {
 434         xen_be_printf(xendev, 1, "not online\n");
 435         return -1;
 436     }
 437
 438     if (xendev->ops->init) {
 439         rc = xendev->ops->init(xendev);
 440     }
 441     if (rc != 0) {
 442         xen_be_printf(xendev, 1, "init() failed\n");
 443         return rc;
 444     }
 445
 446     xenstore_write_be_str(xendev, "hotplug-status", "connected");
 447     xen_be_set_state(xendev, XenbusStateInitWait);
 448     return 0;
 449 }
 450
 451 /*
 452  * Try to initialise xendev.  Depends on the frontend being ready
 453  * for it (shared ring and evtchn info in xenstore, state being
 454  * Initialised or Connected).
 455  *
 456  * Goes to Connected on success.
 457  */
 458 static int xen_be_try_initialise(struct XenDevice *xendev)
 459 {
 460     int rc = 0;
 461
 462     if (xendev->fe_state != XenbusStateInitialised  &&
 463         xendev->fe_state != XenbusStateConnected) {
 464         if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
 465             xen_be_printf(xendev, 2, "frontend not ready, ignoring\n");
 466         } else {
 467             xen_be_printf(xendev, 2, "frontend not ready (yet)\n");
 468             return -1;
 469         }
 470     }
 471
 472     if (xendev->ops->initialise) {
 473         rc = xendev->ops->initialise(xendev);
 474     }
 475     if (rc != 0) {
 476         xen_be_printf(xendev, 0, "initialise() failed\n");
 477         return rc;
 478     }
 479
 480     xen_be_set_state(xendev, XenbusStateConnected);
 481     return 0;
 482 }
 483
 484 /*
 485  * Try to let xendev know that it is connected.  Depends on the
 486  * frontend being Connected.  Note that this may be called more
 487  * than once since the backend state is not modified.
 488  */
 489 static void xen_be_try_connected(struct XenDevice *xendev)
 490 {
 491     if (!xendev->ops->connected) {
 492         return;
 493     }
 494
 495     if (xendev->fe_state != XenbusStateConnected) {
 496         if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
 497             xen_be_printf(xendev, 2, "frontend not ready, ignoring\n");
 498         } else {
 499             xen_be_printf(xendev, 2, "frontend not ready (yet)\n");
 500             return;
 501         }
 502     }
 503
 504     xendev->ops->connected(xendev);
 505 }
 506
 507 /*
 508  * Teardown connection.
 509  *
 510  * Goes to Closed when done.
 511  */
 512 static void xen_be_disconnect(struct XenDevice *xendev, enum xenbus_state state)
 513 {
 514     if (xendev->be_state != XenbusStateClosing &&
 515         xendev->be_state != XenbusStateClosed  &&
 516         xendev->ops->disconnect) {
 517         xendev->ops->disconnect(xendev);
 518     }
 519     if (xendev->be_state != state) {
 520         xen_be_set_state(xendev, state);
 521     }
 522 }
 523
 524 /*
 525  * Try to reset xendev, for reconnection by another frontend instance.
 526  */
 527 static int xen_be_try_reset(struct XenDevice *xendev)
 528 {
 529     if (xendev->fe_state != XenbusStateInitialising) {
 530         return -1;
 531     }
 532
 533     xen_be_printf(xendev, 1, "device reset (for re-connect)\n");
 534     xen_be_set_state(xendev, XenbusStateInitialising);
 535     return 0;
 536 }
 537
 538 /*
 539  * state change dispatcher function
 540  */
 541 void xen_be_check_state(struct XenDevice *xendev)
 542 {
 543     int rc = 0;
 544
 545     /* frontend may request shutdown from almost anywhere */
 546     if (xendev->fe_state == XenbusStateClosing ||
 547         xendev->fe_state == XenbusStateClosed) {
 548         xen_be_disconnect(xendev, xendev->fe_state);
 549         return;
 550     }
 551
 552     /* check for possible backend state transitions */
 553     for (;;) {
 554         switch (xendev->be_state) {
 555         case XenbusStateUnknown:
 556             rc = xen_be_try_setup(xendev);
 557             break;
 558         case XenbusStateInitialising:
 559             rc = xen_be_try_init(xendev);
 560             break;
 561         case XenbusStateInitWait:
 562             rc = xen_be_try_initialise(xendev);
 563             break;
 564         case XenbusStateConnected:
 565             /* xendev->be_state doesn't change */
 566             xen_be_try_connected(xendev);
 567             rc = -1;
 568             break;
 569         case XenbusStateClosed:
 570             rc = xen_be_try_reset(xendev);
 571             break;
 572         default:
 573             rc = -1;
 574         }
 575         if (rc != 0) {
 576             break;
 577         }
 578     }
 579 }
 580
 581 /* ------------------------------------------------------------- */
 582
 583 static int xenstore_scan(const char *type, int dom, struct XenDevOps *ops)
 584 {
 585     struct XenDevice *xendev;
 586     char path[XEN_BUFSIZE], token[XEN_BUFSIZE];
 587     char **dev = NULL;
 588     unsigned int cdev, j;
 589
 590     /* setup watch */
 591     snprintf(token, sizeof(token), "be:%p:%d:%p", type, dom, ops);
 592     snprintf(path, sizeof(path), "backend/%s/%d", type, dom);
 593     if (!xs_watch(xenstore, path, token)) {
 594         xen_be_printf(NULL, 0, "xen be: watching backend path (%s) failed\n", path);
 595         return -1;
 596     }
 597
 598     /* look for backends */
 599     dev = xs_directory(xenstore, 0, path, &cdev);
 600     if (!dev) {
 601         return 0;
 602     }
 603     for (j = 0; j < cdev; j++) {
 604         xendev = xen_be_get_xendev(type, dom, atoi(dev[j]), ops);
 605         if (xendev == NULL) {
 606             continue;
 607         }
 608         xen_be_check_state(xendev);
 609     }
 610     free(dev);
 611     return 0;
 612 }
 613
 614 static void xenstore_update_be(char *watch, char *type, int dom,
 615                                struct XenDevOps *ops)
 616 {
 617     struct XenDevice *xendev;
 618     char path[XEN_BUFSIZE], *bepath;
 619     unsigned int len, dev;
 620
 621     len = snprintf(path, sizeof(path), "backend/%s/%d", type, dom);
 622     if (strncmp(path, watch, len) != 0) {
 623         return;
 624     }
 625     if (sscanf(watch+len, "/%u/%255s", &dev, path) != 2) {
 626         strcpy(path, "");
 627         if (sscanf(watch+len, "/%u", &dev) != 1) {
 628             dev = -1;
 629         }
 630     }
 631     if (dev == -1) {
 632         return;
 633     }
 634
 635     xendev = xen_be_get_xendev(type, dom, dev, ops);
 636     if (xendev != NULL) {
 637         bepath = xs_read(xenstore, 0, xendev->be, &len);
 638         if (bepath == NULL) {
 639             xen_be_del_xendev(dom, dev);
 640         } else {
 641             free(bepath);
 642             xen_be_backend_changed(xendev, path);
 643             xen_be_check_state(xendev);
 644         }
 645     }
 646 }
 647
 648 static void xenstore_update_fe(char *watch, struct XenDevice *xendev)
 649 {
 650     char *node;
 651     unsigned int len;
 652
 653     len = strlen(xendev->fe);
 654     if (strncmp(xendev->fe, watch, len) != 0) {
 655         return;
 656     }
 657     if (watch[len] != '/') {
 658         return;
 659     }
 660     node = watch + len + 1;
 661
 662     xen_be_frontend_changed(xendev, node);
 663     xen_be_check_state(xendev);
 664 }
 665
 666 static void xenstore_update(void *unused)
 667 {
 668     char **vec = NULL;
 669     intptr_t type, ops, ptr;
 670     unsigned int dom, count;
 671
 672     vec = xs_read_watch(xenstore, &count);
 673     if (vec == NULL) {
 674         goto cleanup;
 675     }
 676
 677     if (sscanf(vec[XS_WATCH_TOKEN], "be:%" PRIxPTR ":%d:%" PRIxPTR,
 678                &type, &dom, &ops) == 3) {
 679         xenstore_update_be(vec[XS_WATCH_PATH], (void*)type, dom, (void*)ops);
 680     }
 681     if (sscanf(vec[XS_WATCH_TOKEN], "fe:%" PRIxPTR, &ptr) == 1) {
 682         xenstore_update_fe(vec[XS_WATCH_PATH], (void*)ptr);
 683     }
 684
 685 cleanup:
 686     free(vec);
 687 }
 688
 689 static void xen_be_evtchn_event(void *opaque)
 690 {
 691     struct XenDevice *xendev = opaque;
 692     evtchn_port_t port;
 693
 694     port = xc_evtchn_pending(xendev->evtchndev);
 695     if (port != xendev->local_port) {
 696         xen_be_printf(xendev, 0, "xc_evtchn_pending returned %d (expected %d)\n",
 697                       port, xendev->local_port);
 698         return;
 699     }
 700     xc_evtchn_unmask(xendev->evtchndev, port);
 701
 702     if (xendev->ops->event) {
 703         xendev->ops->event(xendev);
 704     }
 705 }
 706
 707 /* -------------------------------------------------------------------- */
 708
 709 int xen_be_init(void)
 710 {
 711     xenstore = xs_daemon_open();
 712     if (!xenstore) {
 713         xen_be_printf(NULL, 0, "can't connect to xenstored\n");
 714         return -1;
 715     }
 716
 717     qemu_set_fd_handler(xs_fileno(xenstore), xenstore_update, NULL, NULL);
 718
 719     if (xen_xc == XC_HANDLER_INITIAL_VALUE) {
 720         /* Check if xen_init() have been called */
 721         goto err;
 722     }
 723     return 0;
 724
 725 err:
 726     qemu_set_fd_handler(xs_fileno(xenstore), NULL, NULL, NULL);
 727     xs_daemon_close(xenstore);
 728     xenstore = NULL;
 729
 730     return -1;
 731 }
 732
 733 int xen_be_register(const char *type, struct XenDevOps *ops)
 734 {
 735     return xenstore_scan(type, xen_domid, ops);
 736 }
 737
 738 int xen_be_bind_evtchn(struct XenDevice *xendev)
 739 {
 740     if (xendev->local_port != -1) {
 741         return 0;
 742     }
 743     xendev->local_port = xc_evtchn_bind_interdomain
 744         (xendev->evtchndev, xendev->dom, xendev->remote_port);
 745     if (xendev->local_port == -1) {
 746         xen_be_printf(xendev, 0, "xc_evtchn_bind_interdomain failed\n");
 747         return -1;
 748     }
 749     xen_be_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
 750     qemu_set_fd_handler(xc_evtchn_fd(xendev->evtchndev),
 751                         xen_be_evtchn_event, NULL, xendev);
 752     return 0;
 753 }
 754
 755 void xen_be_unbind_evtchn(struct XenDevice *xendev)
 756 {
 757     if (xendev->local_port == -1) {
 758         return;
 759     }
 760     qemu_set_fd_handler(xc_evtchn_fd(xendev->evtchndev), NULL, NULL, NULL);
 761     xc_evtchn_unbind(xendev->evtchndev, xendev->local_port);
 762     xen_be_printf(xendev, 2, "unbind evtchn port %d\n", xendev->local_port);
 763     xendev->local_port = -1;
 764 }
 765
 766 int xen_be_send_notify(struct XenDevice *xendev)
 767 {
 768     return xc_evtchn_notify(xendev->evtchndev, xendev->local_port);
 769 }
 770
 771 /*
 772  * msg_level:
 773  *  0 == errors (stderr + logfile).
 774  *  1 == informative debug messages (logfile only).
 775  *  2 == noisy debug messages (logfile only).
 776  *  3 == will flood your log (logfile only).
 777  */
 778 void xen_be_printf(struct XenDevice *xendev, int msg_level, const char *fmt, ...)
 779 {
 780     va_list args;
 781
 782     if (xendev) {
 783         if (msg_level > xendev->debug) {
 784             return;
 785         }
 786         qemu_log("xen be: %s: ", xendev->name);
 787         if (msg_level == 0) {
 788             fprintf(stderr, "xen be: %s: ", xendev->name);
 789         }
 790     } else {
 791         if (msg_level > debug) {
 792             return;
 793         }
 794         qemu_log("xen be core: ");
 795         if (msg_level == 0) {
 796             fprintf(stderr, "xen be core: ");
 797         }
 798     }
 799     va_start(args, fmt);
 800     qemu_log_vprintf(fmt, args);
 801     va_end(args);
 802     if (msg_level == 0) {
 803         va_start(args, fmt);
 804         vfprintf(stderr, fmt, args);
 805         va_end(args);
 806     }
 807     qemu_log_flush();
 808 }