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 "qemu/osdep.h"
  26 #include <sys/signal.h>
  27
  28 #include "hw/hw.h"
  29 #include "hw/sysbus.h"
  30 #include "sysemu/char.h"
  31 #include "qemu/log.h"
  32 #include "hw/xen/xen_backend.h"
  33
  34 #include <xen/grant_table.h>
  35
  36 #define TYPE_XENSYSDEV "xensysdev"
  37
  38 DeviceState *xen_sysdev;
  39
  40 /* ------------------------------------------------------------- */
  41
  42 /* public */
  43 xc_interface *xen_xc = NULL;
  44 xenforeignmemory_handle *xen_fmem = NULL;
  45 struct xs_handle *xenstore = NULL;
  46 const char *xen_protocol;
  47
  48 /* private */
  49 struct xs_dirs {
  50     char *xs_dir;
  51     QTAILQ_ENTRY(xs_dirs) list;
  52 };
  53 static QTAILQ_HEAD(xs_dirs_head, xs_dirs) xs_cleanup =
  54     QTAILQ_HEAD_INITIALIZER(xs_cleanup);
  55
  56 static QTAILQ_HEAD(XenDeviceHead, XenDevice) xendevs = QTAILQ_HEAD_INITIALIZER(xendevs);
  57 static int debug = 0;
  58
  59 /* ------------------------------------------------------------- */
  60
  61 static void xenstore_cleanup_dir(char *dir)
  62 {
  63     struct xs_dirs *d;
  64
  65     d = g_malloc(sizeof(*d));
  66     d->xs_dir = dir;
  67     QTAILQ_INSERT_TAIL(&xs_cleanup, d, list);
  68 }
  69
  70 void xen_config_cleanup(void)
  71 {
  72     struct xs_dirs *d;
  73
  74     QTAILQ_FOREACH(d, &xs_cleanup, list) {
  75         xs_rm(xenstore, 0, d->xs_dir);
  76     }
  77 }
  78
  79 int xenstore_write_str(const char *base, const char *node, const char *val)
  80 {
  81     char abspath[XEN_BUFSIZE];
  82
  83     snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
  84     if (!xs_write(xenstore, 0, abspath, val, strlen(val))) {
  85         return -1;
  86     }
  87     return 0;
  88 }
  89
  90 char *xenstore_read_str(const char *base, const char *node)
  91 {
  92     char abspath[XEN_BUFSIZE];
  93     unsigned int len;
  94     char *str, *ret = NULL;
  95
  96     snprintf(abspath, sizeof(abspath), "%s/%s", base, node);
  97     str = xs_read(xenstore, 0, abspath, &len);
  98     if (str != NULL) {
  99         /* move to qemu-allocated memory to make sure
 100          * callers can savely g_free() stuff. */
 101         ret = g_strdup(str);
 102         free(str);
 103     }
 104     return ret;
 105 }
 106
 107 int xenstore_mkdir(char *path, int p)
 108 {
 109     struct xs_permissions perms[2] = {
 110         {
 111             .id    = 0, /* set owner: dom0 */
 112         }, {
 113             .id    = xen_domid,
 114             .perms = p,
 115         }
 116     };
 117
 118     if (!xs_mkdir(xenstore, 0, path)) {
 119         xen_be_printf(NULL, 0, "xs_mkdir %s: failed\n", path);
 120         return -1;
 121     }
 122     xenstore_cleanup_dir(g_strdup(path));
 123
 124     if (!xs_set_permissions(xenstore, 0, path, perms, 2)) {
 125         xen_be_printf(NULL, 0, "xs_set_permissions %s: failed\n", path);
 126         return -1;
 127     }
 128     return 0;
 129 }
 130
 131 int xenstore_write_int(const char *base, const char *node, int ival)
 132 {
 133     char val[12];
 134
 135     snprintf(val, sizeof(val), "%d", ival);
 136     return xenstore_write_str(base, node, val);
 137 }
 138
 139 int xenstore_write_int64(const char *base, const char *node, int64_t ival)
 140 {
 141     char val[21];
 142
 143     snprintf(val, sizeof(val), "%"PRId64, ival);
 144     return xenstore_write_str(base, node, val);
 145 }
 146
 147 int xenstore_read_int(const char *base, const char *node, int *ival)
 148 {
 149     char *val;
 150     int rc = -1;
 151
 152     val = xenstore_read_str(base, node);
 153     if (val && 1 == sscanf(val, "%d", ival)) {
 154         rc = 0;
 155     }
 156     g_free(val);
 157     return rc;
 158 }
 159
 160 int xenstore_read_uint64(const char *base, const char *node, uint64_t *uval)
 161 {
 162     char *val;
 163     int rc = -1;
 164
 165     val = xenstore_read_str(base, node);
 166     if (val && 1 == sscanf(val, "%"SCNu64, uval)) {
 167         rc = 0;
 168     }
 169     g_free(val);
 170     return rc;
 171 }
 172
 173 int xenstore_write_be_str(struct XenDevice *xendev, const char *node, const char *val)
 174 {
 175     return xenstore_write_str(xendev->be, node, val);
 176 }
 177
 178 int xenstore_write_be_int(struct XenDevice *xendev, const char *node, int ival)
 179 {
 180     return xenstore_write_int(xendev->be, node, ival);
 181 }
 182
 183 int xenstore_write_be_int64(struct XenDevice *xendev, const char *node, int64_t ival)
 184 {
 185     return xenstore_write_int64(xendev->be, node, ival);
 186 }
 187
 188 char *xenstore_read_be_str(struct XenDevice *xendev, const char *node)
 189 {
 190     return xenstore_read_str(xendev->be, node);
 191 }
 192
 193 int xenstore_read_be_int(struct XenDevice *xendev, const char *node, int *ival)
 194 {
 195     return xenstore_read_int(xendev->be, node, ival);
 196 }
 197
 198 char *xenstore_read_fe_str(struct XenDevice *xendev, const char *node)
 199 {
 200     return xenstore_read_str(xendev->fe, node);
 201 }
 202
 203 int xenstore_read_fe_int(struct XenDevice *xendev, const char *node, int *ival)
 204 {
 205     return xenstore_read_int(xendev->fe, node, ival);
 206 }
 207
 208 int xenstore_read_fe_uint64(struct XenDevice *xendev, const char *node, uint64_t *uval)
 209 {
 210     return xenstore_read_uint64(xendev->fe, node, uval);
 211 }
 212
 213 /* ------------------------------------------------------------- */
 214
 215 const char *xenbus_strstate(enum xenbus_state state)
 216 {
 217     static const char *const name[] = {
 218         [ XenbusStateUnknown      ] = "Unknown",
 219         [ XenbusStateInitialising ] = "Initialising",
 220         [ XenbusStateInitWait     ] = "InitWait",
 221         [ XenbusStateInitialised  ] = "Initialised",
 222         [ XenbusStateConnected    ] = "Connected",
 223         [ XenbusStateClosing      ] = "Closing",
 224         [ XenbusStateClosed       ] = "Closed",
 225     };
 226     return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
 227 }
 228
 229 int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state)
 230 {
 231     int rc;
 232
 233     rc = xenstore_write_be_int(xendev, "state", state);
 234     if (rc < 0) {
 235         return rc;
 236     }
 237     xen_be_printf(xendev, 1, "backend state: %s -> %s\n",
 238                   xenbus_strstate(xendev->be_state), xenbus_strstate(state));
 239     xendev->be_state = state;
 240     return 0;
 241 }
 242
 243 /* ------------------------------------------------------------- */
 244
 245 struct XenDevice *xen_be_find_xendev(const char *type, int dom, int dev)
 246 {
 247     struct XenDevice *xendev;
 248
 249     QTAILQ_FOREACH(xendev, &xendevs, next) {
 250         if (xendev->dom != dom) {
 251             continue;
 252         }
 253         if (xendev->dev != dev) {
 254             continue;
 255         }
 256         if (strcmp(xendev->type, type) != 0) {
 257             continue;
 258         }
 259         return xendev;
 260     }
 261     return NULL;
 262 }
 263
 264 /*
 265  * get xen backend device, allocate a new one if it doesn't exist.
 266  */
 267 static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
 268                                            struct XenDevOps *ops)
 269 {
 270     struct XenDevice *xendev;
 271
 272     xendev = xen_be_find_xendev(type, dom, dev);
 273     if (xendev) {
 274         return xendev;
 275     }
 276
 277     /* init new xendev */
 278     xendev = g_malloc0(ops->size);
 279     xendev->type  = type;
 280     xendev->dom   = dom;
 281     xendev->dev   = dev;
 282     xendev->ops   = ops;
 283
 284     snprintf(xendev->be, sizeof(xendev->be), "backend/%s/%d/%d",
 285              xendev->type, xendev->dom, xendev->dev);
 286     snprintf(xendev->name, sizeof(xendev->name), "%s-%d",
 287              xendev->type, xendev->dev);
 288
 289     xendev->debug      = debug;
 290     xendev->local_port = -1;
 291
 292     xendev->evtchndev = xenevtchn_open(NULL, 0);
 293     if (xendev->evtchndev == NULL) {
 294         xen_be_printf(NULL, 0, "can't open evtchn device\n");
 295         g_free(xendev);
 296         return NULL;
 297     }
 298     fcntl(xenevtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC);
 299
 300     if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
 301         xendev->gnttabdev = xengnttab_open(NULL, 0);
 302         if (xendev->gnttabdev == NULL) {
 303             xen_be_printf(NULL, 0, "can't open gnttab device\n");
 304             xenevtchn_close(xendev->evtchndev);
 305             g_free(xendev);
 306             return NULL;
 307         }
 308     } else {
 309         xendev->gnttabdev = NULL;
 310     }
 311
 312     QTAILQ_INSERT_TAIL(&xendevs, xendev, next);
 313
 314     if (xendev->ops->alloc) {
 315         xendev->ops->alloc(xendev);
 316     }
 317
 318     return xendev;
 319 }
 320
 321 /*
 322  * release xen backend device.
 323  */
 324 static struct XenDevice *xen_be_del_xendev(int dom, int dev)
 325 {
 326     struct XenDevice *xendev, *xnext;
 327
 328     /*
 329      * This is pretty much like QTAILQ_FOREACH(xendev, &xendevs, next) but
 330      * we save the next pointer in xnext because we might free xendev.
 331      */
 332     xnext = xendevs.tqh_first;
 333     while (xnext) {
 334         xendev = xnext;
 335         xnext = xendev->next.tqe_next;
 336
 337         if (xendev->dom != dom) {
 338             continue;
 339         }
 340         if (xendev->dev != dev && dev != -1) {
 341             continue;
 342         }
 343
 344         if (xendev->ops->free) {
 345             xendev->ops->free(xendev);
 346         }
 347
 348         if (xendev->fe) {
 349             char token[XEN_BUFSIZE];
 350             snprintf(token, sizeof(token), "fe:%p", xendev);
 351             xs_unwatch(xenstore, xendev->fe, token);
 352             g_free(xendev->fe);
 353         }
 354
 355         if (xendev->evtchndev != NULL) {
 356             xenevtchn_close(xendev->evtchndev);
 357         }
 358         if (xendev->gnttabdev != NULL) {
 359             xengnttab_close(xendev->gnttabdev);
 360         }
 361
 362         QTAILQ_REMOVE(&xendevs, xendev, next);
 363         g_free(xendev);
 364     }
 365     return NULL;
 366 }
 367
 368 /*
 369  * Sync internal data structures on xenstore updates.
 370  * Node specifies the changed field.  node = NULL means
 371  * update all fields (used for initialization).
 372  */
 373 static void xen_be_backend_changed(struct XenDevice *xendev, const char *node)
 374 {
 375     if (node == NULL  ||  strcmp(node, "online") == 0) {
 376         if (xenstore_read_be_int(xendev, "online", &xendev->online) == -1) {
 377             xendev->online = 0;
 378         }
 379     }
 380
 381     if (node) {
 382         xen_be_printf(xendev, 2, "backend update: %s\n", node);
 383         if (xendev->ops->backend_changed) {
 384             xendev->ops->backend_changed(xendev, node);
 385         }
 386     }
 387 }
 388
 389 static void xen_be_frontend_changed(struct XenDevice *xendev, const char *node)
 390 {
 391     int fe_state;
 392
 393     if (node == NULL  ||  strcmp(node, "state") == 0) {
 394         if (xenstore_read_fe_int(xendev, "state", &fe_state) == -1) {
 395             fe_state = XenbusStateUnknown;
 396         }
 397         if (xendev->fe_state != fe_state) {
 398             xen_be_printf(xendev, 1, "frontend state: %s -> %s\n",
 399                           xenbus_strstate(xendev->fe_state),
 400                           xenbus_strstate(fe_state));
 401         }
 402         xendev->fe_state = fe_state;
 403     }
 404     if (node == NULL  ||  strcmp(node, "protocol") == 0) {
 405         g_free(xendev->protocol);
 406         xendev->protocol = xenstore_read_fe_str(xendev, "protocol");
 407         if (xendev->protocol) {
 408             xen_be_printf(xendev, 1, "frontend protocol: %s\n", xendev->protocol);
 409         }
 410     }
 411
 412     if (node) {
 413         xen_be_printf(xendev, 2, "frontend update: %s\n", node);
 414         if (xendev->ops->frontend_changed) {
 415             xendev->ops->frontend_changed(xendev, node);
 416         }
 417     }
 418 }
 419
 420 /* ------------------------------------------------------------- */
 421 /* Check for possible state transitions and perform them.        */
 422
 423 /*
 424  * Initial xendev setup.  Read frontend path, register watch for it.
 425  * Should succeed once xend finished setting up the backend device.
 426  *
 427  * Also sets initial state (-> Initializing) when done.  Which
 428  * only affects the xendev->be_state variable as xenbus should
 429  * already be put into that state by xend.
 430  */
 431 static int xen_be_try_setup(struct XenDevice *xendev)
 432 {
 433     char token[XEN_BUFSIZE];
 434     int be_state;
 435
 436     if (xenstore_read_be_int(xendev, "state", &be_state) == -1) {
 437         xen_be_printf(xendev, 0, "reading backend state failed\n");
 438         return -1;
 439     }
 440
 441     if (be_state != XenbusStateInitialising) {
 442         xen_be_printf(xendev, 0, "initial backend state is wrong (%s)\n",
 443                       xenbus_strstate(be_state));
 444         return -1;
 445     }
 446
 447     xendev->fe = xenstore_read_be_str(xendev, "frontend");
 448     if (xendev->fe == NULL) {
 449         xen_be_printf(xendev, 0, "reading frontend path failed\n");
 450         return -1;
 451     }
 452
 453     /* setup frontend watch */
 454     snprintf(token, sizeof(token), "fe:%p", xendev);
 455     if (!xs_watch(xenstore, xendev->fe, token)) {
 456         xen_be_printf(xendev, 0, "watching frontend path (%s) failed\n",
 457                       xendev->fe);
 458         return -1;
 459     }
 460     xen_be_set_state(xendev, XenbusStateInitialising);
 461
 462     xen_be_backend_changed(xendev, NULL);
 463     xen_be_frontend_changed(xendev, NULL);
 464     return 0;
 465 }
 466
 467 /*
 468  * Try initialize xendev.  Prepare everything the backend can do
 469  * without synchronizing with the frontend.  Fakes hotplug-status.  No
 470  * hotplug involved here because this is about userspace drivers, thus
 471  * there are kernel backend devices which could invoke hotplug.
 472  *
 473  * Goes to InitWait on success.
 474  */
 475 static int xen_be_try_init(struct XenDevice *xendev)
 476 {
 477     int rc = 0;
 478
 479     if (!xendev->online) {
 480         xen_be_printf(xendev, 1, "not online\n");
 481         return -1;
 482     }
 483
 484     if (xendev->ops->init) {
 485         rc = xendev->ops->init(xendev);
 486     }
 487     if (rc != 0) {
 488         xen_be_printf(xendev, 1, "init() failed\n");
 489         return rc;
 490     }
 491
 492     xenstore_write_be_str(xendev, "hotplug-status", "connected");
 493     xen_be_set_state(xendev, XenbusStateInitWait);
 494     return 0;
 495 }
 496
 497 /*
 498  * Try to initialise xendev.  Depends on the frontend being ready
 499  * for it (shared ring and evtchn info in xenstore, state being
 500  * Initialised or Connected).
 501  *
 502  * Goes to Connected on success.
 503  */
 504 static int xen_be_try_initialise(struct XenDevice *xendev)
 505 {
 506     int rc = 0;
 507
 508     if (xendev->fe_state != XenbusStateInitialised  &&
 509         xendev->fe_state != XenbusStateConnected) {
 510         if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
 511             xen_be_printf(xendev, 2, "frontend not ready, ignoring\n");
 512         } else {
 513             xen_be_printf(xendev, 2, "frontend not ready (yet)\n");
 514             return -1;
 515         }
 516     }
 517
 518     if (xendev->ops->initialise) {
 519         rc = xendev->ops->initialise(xendev);
 520     }
 521     if (rc != 0) {
 522         xen_be_printf(xendev, 0, "initialise() failed\n");
 523         return rc;
 524     }
 525
 526     xen_be_set_state(xendev, XenbusStateConnected);
 527     return 0;
 528 }
 529
 530 /*
 531  * Try to let xendev know that it is connected.  Depends on the
 532  * frontend being Connected.  Note that this may be called more
 533  * than once since the backend state is not modified.
 534  */
 535 static void xen_be_try_connected(struct XenDevice *xendev)
 536 {
 537     if (!xendev->ops->connected) {
 538         return;
 539     }
 540
 541     if (xendev->fe_state != XenbusStateConnected) {
 542         if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
 543             xen_be_printf(xendev, 2, "frontend not ready, ignoring\n");
 544         } else {
 545             xen_be_printf(xendev, 2, "frontend not ready (yet)\n");
 546             return;
 547         }
 548     }
 549
 550     xendev->ops->connected(xendev);
 551 }
 552
 553 /*
 554  * Teardown connection.
 555  *
 556  * Goes to Closed when done.
 557  */
 558 static void xen_be_disconnect(struct XenDevice *xendev, enum xenbus_state state)
 559 {
 560     if (xendev->be_state != XenbusStateClosing &&
 561         xendev->be_state != XenbusStateClosed  &&
 562         xendev->ops->disconnect) {
 563         xendev->ops->disconnect(xendev);
 564     }
 565     if (xendev->be_state != state) {
 566         xen_be_set_state(xendev, state);
 567     }
 568 }
 569
 570 /*
 571  * Try to reset xendev, for reconnection by another frontend instance.
 572  */
 573 static int xen_be_try_reset(struct XenDevice *xendev)
 574 {
 575     if (xendev->fe_state != XenbusStateInitialising) {
 576         return -1;
 577     }
 578
 579     xen_be_printf(xendev, 1, "device reset (for re-connect)\n");
 580     xen_be_set_state(xendev, XenbusStateInitialising);
 581     return 0;
 582 }
 583
 584 /*
 585  * state change dispatcher function
 586  */
 587 void xen_be_check_state(struct XenDevice *xendev)
 588 {
 589     int rc = 0;
 590
 591     /* frontend may request shutdown from almost anywhere */
 592     if (xendev->fe_state == XenbusStateClosing ||
 593         xendev->fe_state == XenbusStateClosed) {
 594         xen_be_disconnect(xendev, xendev->fe_state);
 595         return;
 596     }
 597
 598     /* check for possible backend state transitions */
 599     for (;;) {
 600         switch (xendev->be_state) {
 601         case XenbusStateUnknown:
 602             rc = xen_be_try_setup(xendev);
 603             break;
 604         case XenbusStateInitialising:
 605             rc = xen_be_try_init(xendev);
 606             break;
 607         case XenbusStateInitWait:
 608             rc = xen_be_try_initialise(xendev);
 609             break;
 610         case XenbusStateConnected:
 611             /* xendev->be_state doesn't change */
 612             xen_be_try_connected(xendev);
 613             rc = -1;
 614             break;
 615         case XenbusStateClosed:
 616             rc = xen_be_try_reset(xendev);
 617             break;
 618         default:
 619             rc = -1;
 620         }
 621         if (rc != 0) {
 622             break;
 623         }
 624     }
 625 }
 626
 627 /* ------------------------------------------------------------- */
 628
 629 static int xenstore_scan(const char *type, int dom, struct XenDevOps *ops)
 630 {
 631     struct XenDevice *xendev;
 632     char path[XEN_BUFSIZE], token[XEN_BUFSIZE];
 633     char **dev = NULL;
 634     unsigned int cdev, j;
 635
 636     /* setup watch */
 637     snprintf(token, sizeof(token), "be:%p:%d:%p", type, dom, ops);
 638     snprintf(path, sizeof(path), "backend/%s/%d", type, dom);
 639     if (!xs_watch(xenstore, path, token)) {
 640         xen_be_printf(NULL, 0, "xen be: watching backend path (%s) failed\n", path);
 641         return -1;
 642     }
 643
 644     /* look for backends */
 645     dev = xs_directory(xenstore, 0, path, &cdev);
 646     if (!dev) {
 647         return 0;
 648     }
 649     for (j = 0; j < cdev; j++) {
 650         xendev = xen_be_get_xendev(type, dom, atoi(dev[j]), ops);
 651         if (xendev == NULL) {
 652             continue;
 653         }
 654         xen_be_check_state(xendev);
 655     }
 656     free(dev);
 657     return 0;
 658 }
 659
 660 static void xenstore_update_be(char *watch, char *type, int dom,
 661                                struct XenDevOps *ops)
 662 {
 663     struct XenDevice *xendev;
 664     char path[XEN_BUFSIZE], *bepath;
 665     unsigned int len, dev;
 666
 667     len = snprintf(path, sizeof(path), "backend/%s/%d", type, dom);
 668     if (strncmp(path, watch, len) != 0) {
 669         return;
 670     }
 671     if (sscanf(watch+len, "/%u/%255s", &dev, path) != 2) {
 672         strcpy(path, "");
 673         if (sscanf(watch+len, "/%u", &dev) != 1) {
 674             dev = -1;
 675         }
 676     }
 677     if (dev == -1) {
 678         return;
 679     }
 680
 681     xendev = xen_be_get_xendev(type, dom, dev, ops);
 682     if (xendev != NULL) {
 683         bepath = xs_read(xenstore, 0, xendev->be, &len);
 684         if (bepath == NULL) {
 685             xen_be_del_xendev(dom, dev);
 686         } else {
 687             free(bepath);
 688             xen_be_backend_changed(xendev, path);
 689             xen_be_check_state(xendev);
 690         }
 691     }
 692 }
 693
 694 static void xenstore_update_fe(char *watch, struct XenDevice *xendev)
 695 {
 696     char *node;
 697     unsigned int len;
 698
 699     len = strlen(xendev->fe);
 700     if (strncmp(xendev->fe, watch, len) != 0) {
 701         return;
 702     }
 703     if (watch[len] != '/') {
 704         return;
 705     }
 706     node = watch + len + 1;
 707
 708     xen_be_frontend_changed(xendev, node);
 709     xen_be_check_state(xendev);
 710 }
 711
 712 static void xenstore_update(void *unused)
 713 {
 714     char **vec = NULL;
 715     intptr_t type, ops, ptr;
 716     unsigned int dom, count;
 717
 718     vec = xs_read_watch(xenstore, &count);
 719     if (vec == NULL) {
 720         goto cleanup;
 721     }
 722
 723     if (sscanf(vec[XS_WATCH_TOKEN], "be:%" PRIxPTR ":%d:%" PRIxPTR,
 724                &type, &dom, &ops) == 3) {
 725         xenstore_update_be(vec[XS_WATCH_PATH], (void*)type, dom, (void*)ops);
 726     }
 727     if (sscanf(vec[XS_WATCH_TOKEN], "fe:%" PRIxPTR, &ptr) == 1) {
 728         xenstore_update_fe(vec[XS_WATCH_PATH], (void*)ptr);
 729     }
 730
 731 cleanup:
 732     free(vec);
 733 }
 734
 735 static void xen_be_evtchn_event(void *opaque)
 736 {
 737     struct XenDevice *xendev = opaque;
 738     evtchn_port_t port;
 739
 740     port = xenevtchn_pending(xendev->evtchndev);
 741     if (port != xendev->local_port) {
 742         xen_be_printf(xendev, 0,
 743                       "xenevtchn_pending returned %d (expected %d)\n",
 744                       port, xendev->local_port);
 745         return;
 746     }
 747     xenevtchn_unmask(xendev->evtchndev, port);
 748
 749     if (xendev->ops->event) {
 750         xendev->ops->event(xendev);
 751     }
 752 }
 753
 754 /* -------------------------------------------------------------------- */
 755
 756 int xen_be_init(void)
 757 {
 758     xenstore = xs_daemon_open();
 759     if (!xenstore) {
 760         xen_be_printf(NULL, 0, "can't connect to xenstored\n");
 761         return -1;
 762     }
 763
 764     qemu_set_fd_handler(xs_fileno(xenstore), xenstore_update, NULL, NULL);
 765
 766     if (xen_xc == NULL || xen_fmem == NULL) {
 767         /* Check if xen_init() have been called */
 768         goto err;
 769     }
 770
 771     xen_sysdev = qdev_create(NULL, TYPE_XENSYSDEV);
 772     qdev_init_nofail(xen_sysdev);
 773
 774     return 0;
 775
 776 err:
 777     qemu_set_fd_handler(xs_fileno(xenstore), NULL, NULL, NULL);
 778     xs_daemon_close(xenstore);
 779     xenstore = NULL;
 780
 781     return -1;
 782 }
 783
 784 int xen_be_register(const char *type, struct XenDevOps *ops)
 785 {
 786     char path[50];
 787     int rc;
 788
 789     if (ops->backend_register) {
 790         rc = ops->backend_register();
 791         if (rc) {
 792             return rc;
 793         }
 794     }
 795
 796     snprintf(path, sizeof(path), "device-model/%u/backends/%s", xen_domid,
 797              type);
 798     xenstore_mkdir(path, XS_PERM_NONE);
 799
 800     return xenstore_scan(type, xen_domid, ops);
 801 }
 802
 803 int xen_be_bind_evtchn(struct XenDevice *xendev)
 804 {
 805     if (xendev->local_port != -1) {
 806         return 0;
 807     }
 808     xendev->local_port = xenevtchn_bind_interdomain
 809         (xendev->evtchndev, xendev->dom, xendev->remote_port);
 810     if (xendev->local_port == -1) {
 811         xen_be_printf(xendev, 0, "xenevtchn_bind_interdomain failed\n");
 812         return -1;
 813     }
 814     xen_be_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
 815     qemu_set_fd_handler(xenevtchn_fd(xendev->evtchndev),
 816                         xen_be_evtchn_event, NULL, xendev);
 817     return 0;
 818 }
 819
 820 void xen_be_unbind_evtchn(struct XenDevice *xendev)
 821 {
 822     if (xendev->local_port == -1) {
 823         return;
 824     }
 825     qemu_set_fd_handler(xenevtchn_fd(xendev->evtchndev), NULL, NULL, NULL);
 826     xenevtchn_unbind(xendev->evtchndev, xendev->local_port);
 827     xen_be_printf(xendev, 2, "unbind evtchn port %d\n", xendev->local_port);
 828     xendev->local_port = -1;
 829 }
 830
 831 int xen_be_send_notify(struct XenDevice *xendev)
 832 {
 833     return xenevtchn_notify(xendev->evtchndev, xendev->local_port);
 834 }
 835
 836 /*
 837  * msg_level:
 838  *  0 == errors (stderr + logfile).
 839  *  1 == informative debug messages (logfile only).
 840  *  2 == noisy debug messages (logfile only).
 841  *  3 == will flood your log (logfile only).
 842  */
 843 void xen_be_printf(struct XenDevice *xendev, int msg_level, const char *fmt, ...)
 844 {
 845     va_list args;
 846
 847     if (xendev) {
 848         if (msg_level > xendev->debug) {
 849             return;
 850         }
 851         qemu_log("xen be: %s: ", xendev->name);
 852         if (msg_level == 0) {
 853             fprintf(stderr, "xen be: %s: ", xendev->name);
 854         }
 855     } else {
 856         if (msg_level > debug) {
 857             return;
 858         }
 859         qemu_log("xen be core: ");
 860         if (msg_level == 0) {
 861             fprintf(stderr, "xen be core: ");
 862         }
 863     }
 864     va_start(args, fmt);
 865     qemu_log_vprintf(fmt, args);
 866     va_end(args);
 867     if (msg_level == 0) {
 868         va_start(args, fmt);
 869         vfprintf(stderr, fmt, args);
 870         va_end(args);
 871     }
 872     qemu_log_flush();
 873 }
 874
 875 static int xen_sysdev_init(SysBusDevice *dev)
 876 {
 877     return 0;
 878 }
 879
 880 static Property xen_sysdev_properties[] = {
 881     {/* end of property list */},
 882 };
 883
 884 static void xen_sysdev_class_init(ObjectClass *klass, void *data)
 885 {
 886     DeviceClass *dc = DEVICE_CLASS(klass);
 887     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 888
 889     k->init = xen_sysdev_init;
 890     dc->props = xen_sysdev_properties;
 891 }
 892
 893 static const TypeInfo xensysdev_info = {
 894     .name          = TYPE_XENSYSDEV,
 895     .parent        = TYPE_SYS_BUS_DEVICE,
 896     .instance_size = sizeof(SysBusDevice),
 897     .class_init    = xen_sysdev_class_init,
 898 };
 899
 900 static void xenbe_register_types(void)
 901 {
 902     type_register_static(&xensysdev_info);
 903 }
 904
 905 type_init(xenbe_register_types);