migration/block: rename MAX_INFLIGHT_IO to MAX_IO_BUFFERS
[qemu/kevin.git] / hw / xen / xen_backend.c
blob7445b506ac610dc35283f28072f0dca893d02dff
1 /*
2 * xen backend driver infrastructure
3 * (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
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.
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.
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/>.
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.
22 * TODO: add some xenbus / xenstore concepts overview here.
25 #include "qemu/osdep.h"
26 #include <sys/signal.h>
28 #include "hw/hw.h"
29 #include "hw/sysbus.h"
30 #include "hw/boards.h"
31 #include "qemu/log.h"
32 #include "qapi/error.h"
33 #include "hw/xen/xen_backend.h"
34 #include "hw/xen/xen_pvdev.h"
35 #include "monitor/qdev.h"
37 #include <xen/grant_table.h>
39 DeviceState *xen_sysdev;
40 BusState *xen_sysbus;
42 /* ------------------------------------------------------------- */
44 /* public */
45 struct xs_handle *xenstore = NULL;
46 const char *xen_protocol;
47 bool xen_feature_grant_copy;
49 /* private */
50 static int debug;
52 int xenstore_write_be_str(struct XenDevice *xendev, const char *node, const char *val)
54 return xenstore_write_str(xendev->be, node, val);
57 int xenstore_write_be_int(struct XenDevice *xendev, const char *node, int ival)
59 return xenstore_write_int(xendev->be, node, ival);
62 int xenstore_write_be_int64(struct XenDevice *xendev, const char *node, int64_t ival)
64 return xenstore_write_int64(xendev->be, node, ival);
67 char *xenstore_read_be_str(struct XenDevice *xendev, const char *node)
69 return xenstore_read_str(xendev->be, node);
72 int xenstore_read_be_int(struct XenDevice *xendev, const char *node, int *ival)
74 return xenstore_read_int(xendev->be, node, ival);
77 char *xenstore_read_fe_str(struct XenDevice *xendev, const char *node)
79 return xenstore_read_str(xendev->fe, node);
82 int xenstore_read_fe_int(struct XenDevice *xendev, const char *node, int *ival)
84 return xenstore_read_int(xendev->fe, node, ival);
87 int xenstore_read_fe_uint64(struct XenDevice *xendev, const char *node,
88 uint64_t *uval)
90 return xenstore_read_uint64(xendev->fe, node, uval);
93 /* ------------------------------------------------------------- */
95 int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state)
97 int rc;
99 rc = xenstore_write_be_int(xendev, "state", state);
100 if (rc < 0) {
101 return rc;
103 xen_pv_printf(xendev, 1, "backend state: %s -> %s\n",
104 xenbus_strstate(xendev->be_state), xenbus_strstate(state));
105 xendev->be_state = state;
106 return 0;
110 * get xen backend device, allocate a new one if it doesn't exist.
112 static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
113 struct XenDevOps *ops)
115 struct XenDevice *xendev;
117 xendev = xen_pv_find_xendev(type, dom, dev);
118 if (xendev) {
119 return xendev;
122 /* init new xendev */
123 xendev = g_malloc0(ops->size);
124 object_initialize(&xendev->qdev, ops->size, TYPE_XENBACKEND);
125 OBJECT(xendev)->free = g_free;
126 qdev_set_parent_bus(DEVICE(xendev), xen_sysbus);
127 qdev_set_id(DEVICE(xendev), g_strdup_printf("xen-%s-%d", type, dev));
128 qdev_init_nofail(DEVICE(xendev));
129 object_unref(OBJECT(xendev));
131 xendev->type = type;
132 xendev->dom = dom;
133 xendev->dev = dev;
134 xendev->ops = ops;
136 snprintf(xendev->be, sizeof(xendev->be), "backend/%s/%d/%d",
137 xendev->type, xendev->dom, xendev->dev);
138 snprintf(xendev->name, sizeof(xendev->name), "%s-%d",
139 xendev->type, xendev->dev);
141 xendev->debug = debug;
142 xendev->local_port = -1;
144 xendev->evtchndev = xenevtchn_open(NULL, 0);
145 if (xendev->evtchndev == NULL) {
146 xen_pv_printf(NULL, 0, "can't open evtchn device\n");
147 qdev_unplug(DEVICE(xendev), NULL);
148 return NULL;
150 qemu_set_cloexec(xenevtchn_fd(xendev->evtchndev));
152 if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
153 xendev->gnttabdev = xengnttab_open(NULL, 0);
154 if (xendev->gnttabdev == NULL) {
155 xen_pv_printf(NULL, 0, "can't open gnttab device\n");
156 xenevtchn_close(xendev->evtchndev);
157 qdev_unplug(DEVICE(xendev), NULL);
158 return NULL;
160 } else {
161 xendev->gnttabdev = NULL;
164 xen_pv_insert_xendev(xendev);
166 if (xendev->ops->alloc) {
167 xendev->ops->alloc(xendev);
170 return xendev;
175 * Sync internal data structures on xenstore updates.
176 * Node specifies the changed field. node = NULL means
177 * update all fields (used for initialization).
179 static void xen_be_backend_changed(struct XenDevice *xendev, const char *node)
181 if (node == NULL || strcmp(node, "online") == 0) {
182 if (xenstore_read_be_int(xendev, "online", &xendev->online) == -1) {
183 xendev->online = 0;
187 if (node) {
188 xen_pv_printf(xendev, 2, "backend update: %s\n", node);
189 if (xendev->ops->backend_changed) {
190 xendev->ops->backend_changed(xendev, node);
195 static void xen_be_frontend_changed(struct XenDevice *xendev, const char *node)
197 int fe_state;
199 if (node == NULL || strcmp(node, "state") == 0) {
200 if (xenstore_read_fe_int(xendev, "state", &fe_state) == -1) {
201 fe_state = XenbusStateUnknown;
203 if (xendev->fe_state != fe_state) {
204 xen_pv_printf(xendev, 1, "frontend state: %s -> %s\n",
205 xenbus_strstate(xendev->fe_state),
206 xenbus_strstate(fe_state));
208 xendev->fe_state = fe_state;
210 if (node == NULL || strcmp(node, "protocol") == 0) {
211 g_free(xendev->protocol);
212 xendev->protocol = xenstore_read_fe_str(xendev, "protocol");
213 if (xendev->protocol) {
214 xen_pv_printf(xendev, 1, "frontend protocol: %s\n",
215 xendev->protocol);
219 if (node) {
220 xen_pv_printf(xendev, 2, "frontend update: %s\n", node);
221 if (xendev->ops->frontend_changed) {
222 xendev->ops->frontend_changed(xendev, node);
227 /* ------------------------------------------------------------- */
228 /* Check for possible state transitions and perform them. */
231 * Initial xendev setup. Read frontend path, register watch for it.
232 * Should succeed once xend finished setting up the backend device.
234 * Also sets initial state (-> Initializing) when done. Which
235 * only affects the xendev->be_state variable as xenbus should
236 * already be put into that state by xend.
238 static int xen_be_try_setup(struct XenDevice *xendev)
240 char token[XEN_BUFSIZE];
241 int be_state;
243 if (xenstore_read_be_int(xendev, "state", &be_state) == -1) {
244 xen_pv_printf(xendev, 0, "reading backend state failed\n");
245 return -1;
248 if (be_state != XenbusStateInitialising) {
249 xen_pv_printf(xendev, 0, "initial backend state is wrong (%s)\n",
250 xenbus_strstate(be_state));
251 return -1;
254 xendev->fe = xenstore_read_be_str(xendev, "frontend");
255 if (xendev->fe == NULL) {
256 xen_pv_printf(xendev, 0, "reading frontend path failed\n");
257 return -1;
260 /* setup frontend watch */
261 snprintf(token, sizeof(token), "fe:%p", xendev);
262 if (!xs_watch(xenstore, xendev->fe, token)) {
263 xen_pv_printf(xendev, 0, "watching frontend path (%s) failed\n",
264 xendev->fe);
265 return -1;
267 xen_be_set_state(xendev, XenbusStateInitialising);
269 xen_be_backend_changed(xendev, NULL);
270 xen_be_frontend_changed(xendev, NULL);
271 return 0;
275 * Try initialize xendev. Prepare everything the backend can do
276 * without synchronizing with the frontend. Fakes hotplug-status. No
277 * hotplug involved here because this is about userspace drivers, thus
278 * there are kernel backend devices which could invoke hotplug.
280 * Goes to InitWait on success.
282 static int xen_be_try_init(struct XenDevice *xendev)
284 int rc = 0;
286 if (!xendev->online) {
287 xen_pv_printf(xendev, 1, "not online\n");
288 return -1;
291 if (xendev->ops->init) {
292 rc = xendev->ops->init(xendev);
294 if (rc != 0) {
295 xen_pv_printf(xendev, 1, "init() failed\n");
296 return rc;
299 xenstore_write_be_str(xendev, "hotplug-status", "connected");
300 xen_be_set_state(xendev, XenbusStateInitWait);
301 return 0;
305 * Try to initialise xendev. Depends on the frontend being ready
306 * for it (shared ring and evtchn info in xenstore, state being
307 * Initialised or Connected).
309 * Goes to Connected on success.
311 static int xen_be_try_initialise(struct XenDevice *xendev)
313 int rc = 0;
315 if (xendev->fe_state != XenbusStateInitialised &&
316 xendev->fe_state != XenbusStateConnected) {
317 if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
318 xen_pv_printf(xendev, 2, "frontend not ready, ignoring\n");
319 } else {
320 xen_pv_printf(xendev, 2, "frontend not ready (yet)\n");
321 return -1;
325 if (xendev->ops->initialise) {
326 rc = xendev->ops->initialise(xendev);
328 if (rc != 0) {
329 xen_pv_printf(xendev, 0, "initialise() failed\n");
330 return rc;
333 xen_be_set_state(xendev, XenbusStateConnected);
334 return 0;
338 * Try to let xendev know that it is connected. Depends on the
339 * frontend being Connected. Note that this may be called more
340 * than once since the backend state is not modified.
342 static void xen_be_try_connected(struct XenDevice *xendev)
344 if (!xendev->ops->connected) {
345 return;
348 if (xendev->fe_state != XenbusStateConnected) {
349 if (xendev->ops->flags & DEVOPS_FLAG_IGNORE_STATE) {
350 xen_pv_printf(xendev, 2, "frontend not ready, ignoring\n");
351 } else {
352 xen_pv_printf(xendev, 2, "frontend not ready (yet)\n");
353 return;
357 xendev->ops->connected(xendev);
361 * Teardown connection.
363 * Goes to Closed when done.
365 static void xen_be_disconnect(struct XenDevice *xendev, enum xenbus_state state)
367 if (xendev->be_state != XenbusStateClosing &&
368 xendev->be_state != XenbusStateClosed &&
369 xendev->ops->disconnect) {
370 xendev->ops->disconnect(xendev);
372 if (xendev->be_state != state) {
373 xen_be_set_state(xendev, state);
378 * Try to reset xendev, for reconnection by another frontend instance.
380 static int xen_be_try_reset(struct XenDevice *xendev)
382 if (xendev->fe_state != XenbusStateInitialising) {
383 return -1;
386 xen_pv_printf(xendev, 1, "device reset (for re-connect)\n");
387 xen_be_set_state(xendev, XenbusStateInitialising);
388 return 0;
392 * state change dispatcher function
394 void xen_be_check_state(struct XenDevice *xendev)
396 int rc = 0;
398 /* frontend may request shutdown from almost anywhere */
399 if (xendev->fe_state == XenbusStateClosing ||
400 xendev->fe_state == XenbusStateClosed) {
401 xen_be_disconnect(xendev, xendev->fe_state);
402 return;
405 /* check for possible backend state transitions */
406 for (;;) {
407 switch (xendev->be_state) {
408 case XenbusStateUnknown:
409 rc = xen_be_try_setup(xendev);
410 break;
411 case XenbusStateInitialising:
412 rc = xen_be_try_init(xendev);
413 break;
414 case XenbusStateInitWait:
415 rc = xen_be_try_initialise(xendev);
416 break;
417 case XenbusStateConnected:
418 /* xendev->be_state doesn't change */
419 xen_be_try_connected(xendev);
420 rc = -1;
421 break;
422 case XenbusStateClosed:
423 rc = xen_be_try_reset(xendev);
424 break;
425 default:
426 rc = -1;
428 if (rc != 0) {
429 break;
434 /* ------------------------------------------------------------- */
436 static int xenstore_scan(const char *type, int dom, struct XenDevOps *ops)
438 struct XenDevice *xendev;
439 char path[XEN_BUFSIZE], token[XEN_BUFSIZE];
440 char **dev = NULL;
441 unsigned int cdev, j;
443 /* setup watch */
444 snprintf(token, sizeof(token), "be:%p:%d:%p", type, dom, ops);
445 snprintf(path, sizeof(path), "backend/%s/%d", type, dom);
446 if (!xs_watch(xenstore, path, token)) {
447 xen_pv_printf(NULL, 0, "xen be: watching backend path (%s) failed\n",
448 path);
449 return -1;
452 /* look for backends */
453 dev = xs_directory(xenstore, 0, path, &cdev);
454 if (!dev) {
455 return 0;
457 for (j = 0; j < cdev; j++) {
458 xendev = xen_be_get_xendev(type, dom, atoi(dev[j]), ops);
459 if (xendev == NULL) {
460 continue;
462 xen_be_check_state(xendev);
464 free(dev);
465 return 0;
468 void xenstore_update_be(char *watch, char *type, int dom,
469 struct XenDevOps *ops)
471 struct XenDevice *xendev;
472 char path[XEN_BUFSIZE], *bepath;
473 unsigned int len, dev;
475 len = snprintf(path, sizeof(path), "backend/%s/%d", type, dom);
476 if (strncmp(path, watch, len) != 0) {
477 return;
479 if (sscanf(watch+len, "/%u/%255s", &dev, path) != 2) {
480 strcpy(path, "");
481 if (sscanf(watch+len, "/%u", &dev) != 1) {
482 dev = -1;
485 if (dev == -1) {
486 return;
489 xendev = xen_be_get_xendev(type, dom, dev, ops);
490 if (xendev != NULL) {
491 bepath = xs_read(xenstore, 0, xendev->be, &len);
492 if (bepath == NULL) {
493 xen_pv_del_xendev(xendev);
494 } else {
495 free(bepath);
496 xen_be_backend_changed(xendev, path);
497 xen_be_check_state(xendev);
502 void xenstore_update_fe(char *watch, struct XenDevice *xendev)
504 char *node;
505 unsigned int len;
507 len = strlen(xendev->fe);
508 if (strncmp(xendev->fe, watch, len) != 0) {
509 return;
511 if (watch[len] != '/') {
512 return;
514 node = watch + len + 1;
516 xen_be_frontend_changed(xendev, node);
517 xen_be_check_state(xendev);
519 /* -------------------------------------------------------------------- */
521 int xen_be_init(void)
523 xengnttab_handle *gnttabdev;
525 xenstore = xs_daemon_open();
526 if (!xenstore) {
527 xen_pv_printf(NULL, 0, "can't connect to xenstored\n");
528 return -1;
531 qemu_set_fd_handler(xs_fileno(xenstore), xenstore_update, NULL, NULL);
533 if (xen_xc == NULL || xen_fmem == NULL) {
534 /* Check if xen_init() have been called */
535 goto err;
538 gnttabdev = xengnttab_open(NULL, 0);
539 if (gnttabdev != NULL) {
540 if (xengnttab_grant_copy(gnttabdev, 0, NULL) == 0) {
541 xen_feature_grant_copy = true;
543 xengnttab_close(gnttabdev);
546 xen_sysdev = qdev_create(NULL, TYPE_XENSYSDEV);
547 qdev_init_nofail(xen_sysdev);
548 xen_sysbus = qbus_create(TYPE_XENSYSBUS, DEVICE(xen_sysdev), "xen-sysbus");
549 qbus_set_bus_hotplug_handler(xen_sysbus, &error_abort);
551 return 0;
553 err:
554 qemu_set_fd_handler(xs_fileno(xenstore), NULL, NULL, NULL);
555 xs_daemon_close(xenstore);
556 xenstore = NULL;
558 return -1;
561 static void xen_set_dynamic_sysbus(void)
563 Object *machine = qdev_get_machine();
564 ObjectClass *oc = object_get_class(machine);
565 MachineClass *mc = MACHINE_CLASS(oc);
567 machine_class_allow_dynamic_sysbus_dev(mc, TYPE_XENSYSDEV);
570 int xen_be_register(const char *type, struct XenDevOps *ops)
572 char path[50];
573 int rc;
575 if (ops->backend_register) {
576 rc = ops->backend_register();
577 if (rc) {
578 return rc;
582 snprintf(path, sizeof(path), "device-model/%u/backends/%s", xen_domid,
583 type);
584 xenstore_mkdir(path, XS_PERM_NONE);
586 return xenstore_scan(type, xen_domid, ops);
589 void xen_be_register_common(void)
591 xen_set_dynamic_sysbus();
593 xen_be_register("console", &xen_console_ops);
594 xen_be_register("vkbd", &xen_kbdmouse_ops);
595 xen_be_register("qdisk", &xen_blkdev_ops);
596 #ifdef CONFIG_VIRTFS
597 xen_be_register("9pfs", &xen_9pfs_ops);
598 #endif
599 #ifdef CONFIG_USB_LIBUSB
600 xen_be_register("qusb", &xen_usb_ops);
601 #endif
604 int xen_be_bind_evtchn(struct XenDevice *xendev)
606 if (xendev->local_port != -1) {
607 return 0;
609 xendev->local_port = xenevtchn_bind_interdomain
610 (xendev->evtchndev, xendev->dom, xendev->remote_port);
611 if (xendev->local_port == -1) {
612 xen_pv_printf(xendev, 0, "xenevtchn_bind_interdomain failed\n");
613 return -1;
615 xen_pv_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port);
616 qemu_set_fd_handler(xenevtchn_fd(xendev->evtchndev),
617 xen_pv_evtchn_event, NULL, xendev);
618 return 0;
622 static Property xendev_properties[] = {
623 DEFINE_PROP_END_OF_LIST(),
626 static void xendev_class_init(ObjectClass *klass, void *data)
628 DeviceClass *dc = DEVICE_CLASS(klass);
630 dc->props = xendev_properties;
631 set_bit(DEVICE_CATEGORY_MISC, dc->categories);
632 /* xen-backend devices can be plugged/unplugged dynamically */
633 dc->user_creatable = true;
636 static const TypeInfo xendev_type_info = {
637 .name = TYPE_XENBACKEND,
638 .parent = TYPE_XENSYSDEV,
639 .class_init = xendev_class_init,
640 .instance_size = sizeof(struct XenDevice),
643 static void xen_sysbus_class_init(ObjectClass *klass, void *data)
645 HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
647 hc->unplug = qdev_simple_device_unplug_cb;
650 static const TypeInfo xensysbus_info = {
651 .name = TYPE_XENSYSBUS,
652 .parent = TYPE_BUS,
653 .class_init = xen_sysbus_class_init,
654 .interfaces = (InterfaceInfo[]) {
655 { TYPE_HOTPLUG_HANDLER },
660 static int xen_sysdev_init(SysBusDevice *dev)
662 return 0;
665 static Property xen_sysdev_properties[] = {
666 {/* end of property list */},
669 static void xen_sysdev_class_init(ObjectClass *klass, void *data)
671 DeviceClass *dc = DEVICE_CLASS(klass);
672 SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
674 k->init = xen_sysdev_init;
675 dc->props = xen_sysdev_properties;
676 dc->bus_type = TYPE_XENSYSBUS;
679 static const TypeInfo xensysdev_info = {
680 .name = TYPE_XENSYSDEV,
681 .parent = TYPE_SYS_BUS_DEVICE,
682 .instance_size = sizeof(SysBusDevice),
683 .class_init = xen_sysdev_class_init,
686 static void xenbe_register_types(void)
688 type_register_static(&xensysbus_info);
689 type_register_static(&xensysdev_info);
690 type_register_static(&xendev_type_info);
693 type_init(xenbe_register_types)