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