xref: /titanic_41/usr/src/uts/common/xen/io/xenbus_dev.c (revision b509e89b2befbaa42939abad9da1d7f5a8c6aaae)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * xenbus_dev.c
29  *
30  * Driver giving user-space access to the kernel's xenbus connection
31  * to xenstore.
32  *
33  * Copyright (c) 2005, Christian Limpach
34  * Copyright (c) 2005, Rusty Russell, IBM Corporation
35  *
36  * This file may be distributed separately from the Linux kernel, or
37  * incorporated into other software packages, subject to the following license:
38  *
39  * Permission is hereby granted, free of charge, to any person obtaining a copy
40  * of this source file (the "Software"), to deal in the Software without
41  * restriction, including without limitation the rights to use, copy, modify,
42  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
43  * and to permit persons to whom the Software is furnished to do so, subject to
44  * the following conditions:
45  *
46  * The above copyright notice and this permission notice shall be included in
47  * all copies or substantial portions of the Software.
48  *
49  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
50  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
51  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
52  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
53  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
54  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
55  * IN THE SOFTWARE.
56  */
57 
58 
59 #include <sys/types.h>
60 #include <sys/sysmacros.h>
61 #include <sys/conf.h>
62 #include <sys/stat.h>
63 #include <sys/modctl.h>
64 #include <sys/uio.h>
65 #include <sys/list.h>
66 #include <sys/file.h>
67 #include <sys/errno.h>
68 #include <sys/open.h>
69 #include <sys/cred.h>
70 #include <sys/condvar.h>
71 #include <sys/ddi.h>
72 #include <sys/sunddi.h>
73 #include <sys/policy.h>
74 
75 #ifdef XPV_HVM_DRIVER
76 #include <public/io/xenbus.h>
77 #include <public/io/xs_wire.h>
78 #include <sys/xpv_support.h>
79 #endif
80 #include <sys/hypervisor.h>
81 #include <xen/sys/xenbus.h>
82 #include <xen/sys/xenbus_comms.h>
83 #include <xen/sys/xenbus_impl.h>
84 #include <xen/public/io/xs_wire.h>
85 
86 #ifdef DEBUG
87 #define	XENBUSDRV_DBPRINT(fmt) { if (xenbusdrv_debug) cmn_err fmt; }
88 #else
89 #define	XENBUSDRV_DBPRINT(fmt)
90 #endif /* ifdef DEBUG */
91 
92 /* Some handy macros */
93 #define	XENBUSDRV_MASK_READ_IDX(idx)	((idx) & (PAGESIZE - 1))
94 #define	XENBUSDRV_MINOR2INST(minor)	((int)(minor))
95 #define	XENBUSDRV_NCLONES 		256
96 #define	XENBUSDRV_INST2SOFTS(instance)	\
97 	((xenbus_dev_t *)ddi_get_soft_state(xenbusdrv_statep, (instance)))
98 
99 static int xenbusdrv_debug = 0;
100 static int xenbusdrv_clone_tab[XENBUSDRV_NCLONES];
101 static dev_info_t *xenbusdrv_dip;
102 static kmutex_t xenbusdrv_clone_tab_mutex;
103 
104 struct xenbus_dev_transaction {
105 	list_t list;
106 	xenbus_transaction_t handle;
107 };
108 
109 /* Soft state data structure for xenbus driver */
110 struct xenbus_dev_data {
111 	dev_info_t *dip;
112 
113 	/* In-progress transaction. */
114 	list_t transactions;
115 
116 	/* Partial request. */
117 	unsigned int len;
118 	union {
119 		struct xsd_sockmsg msg;
120 		char buffer[MMU_PAGESIZE];
121 	} u;
122 
123 	/* Response queue. */
124 	char read_buffer[MMU_PAGESIZE];
125 	unsigned int read_cons, read_prod;
126 	kcondvar_t read_cv;
127 	kmutex_t read_mutex;
128 	int xenstore_inst;
129 };
130 typedef struct xenbus_dev_data xenbus_dev_t;
131 static void *xenbusdrv_statep;
132 
133 static int xenbusdrv_info(dev_info_t *, ddi_info_cmd_t, void *, void **);
134 static int xenbusdrv_attach(dev_info_t *, ddi_attach_cmd_t);
135 static int xenbusdrv_detach(dev_info_t *, ddi_detach_cmd_t);
136 static int xenbusdrv_open(dev_t *, int, int, cred_t *);
137 static int xenbusdrv_close(dev_t, int, int, cred_t *);
138 static int xenbusdrv_read(dev_t, struct uio *, cred_t *);
139 static int xenbusdrv_write(dev_t, struct uio *, cred_t *);
140 static int xenbusdrv_devmap(dev_t, devmap_cookie_t, offset_t, size_t, size_t *,
141     uint_t);
142 static int xenbusdrv_segmap(dev_t, off_t, ddi_as_handle_t, caddr_t *, off_t,
143     uint_t, uint_t, uint_t, cred_t *);
144 static int xenbusdrv_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);
145 static int xenbusdrv_queue_reply(xenbus_dev_t *, const struct xsd_sockmsg *,
146     const char *);
147 
148 /* Solaris driver framework */
149 
150 static 	struct cb_ops xenbusdrv_cb_ops = {
151 	xenbusdrv_open,			/* cb_open */
152 	xenbusdrv_close,		/* cb_close */
153 	nodev,				/* cb_strategy */
154 	nodev,				/* cb_print */
155 	nodev,				/* cb_dump */
156 	xenbusdrv_read,			/* cb_read */
157 	xenbusdrv_write,		/* cb_write */
158 	xenbusdrv_ioctl,		/* cb_ioctl */
159 	xenbusdrv_devmap,		/* cb_devmap */
160 	NULL,				/* cb_mmap */
161 	xenbusdrv_segmap,		/* cb_segmap */
162 	nochpoll,			/* cb_chpoll */
163 	ddi_prop_op,			/* cb_prop_op */
164 	0,				/* cb_stream */
165 	D_DEVMAP | D_NEW | D_MP,	/* cb_flag */
166 	CB_REV
167 };
168 
169 static struct dev_ops xenbusdrv_dev_ops = {
170 	DEVO_REV,		/* devo_rev */
171 	0,			/* devo_refcnt */
172 	xenbusdrv_info,		/* devo_getinfo */
173 	nulldev,		/* devo_identify */
174 	nulldev,		/* devo_probe */
175 	xenbusdrv_attach,	/* devo_attach */
176 	xenbusdrv_detach,	/* devo_detach */
177 	nodev,			/* devo_reset */
178 	&xenbusdrv_cb_ops,	/* devo_cb_ops */
179 	NULL,			/* devo_bus_ops */
180 	NULL,			/* devo_power */
181 	ddi_quiesce_not_needed,		/* devo_quiesce */
182 };
183 
184 static struct modldrv modldrv = {
185 	&mod_driverops,		/* Type of module.  This one is a driver */
186 	"virtual bus driver",	/* Name of the module. */
187 	&xenbusdrv_dev_ops	/* driver ops */
188 };
189 
190 static struct modlinkage modlinkage = {
191 	MODREV_1,
192 	&modldrv,
193 	NULL
194 };
195 
196 int
197 _init(void)
198 {
199 	int e;
200 
201 	e = ddi_soft_state_init(&xenbusdrv_statep, sizeof (xenbus_dev_t), 1);
202 	if (e)
203 		return (e);
204 
205 	e = mod_install(&modlinkage);
206 	if (e)
207 		ddi_soft_state_fini(&xenbusdrv_statep);
208 
209 	return (e);
210 }
211 
212 int
213 _fini(void)
214 {
215 	int e;
216 
217 	e = mod_remove(&modlinkage);
218 	if (e)
219 		return (e);
220 
221 	ddi_soft_state_fini(&xenbusdrv_statep);
222 
223 	return (0);
224 }
225 
226 int
227 _info(struct modinfo *modinfop)
228 {
229 	return (mod_info(&modlinkage, modinfop));
230 }
231 
232 /* ARGSUSED */
233 static int
234 xenbusdrv_info(dev_info_t *dip, ddi_info_cmd_t cmd, void *arg, void **result)
235 {
236 	dev_t	dev = (dev_t)arg;
237 	minor_t	minor = getminor(dev);
238 	int	retval;
239 
240 	switch (cmd) {
241 	case DDI_INFO_DEVT2DEVINFO:
242 		if (minor != 0 || xenbusdrv_dip == NULL) {
243 			*result = (void *)NULL;
244 			retval = DDI_FAILURE;
245 		} else {
246 			*result = (void *)xenbusdrv_dip;
247 			retval = DDI_SUCCESS;
248 		}
249 		break;
250 	case DDI_INFO_DEVT2INSTANCE:
251 		*result = (void *)0;
252 		retval = DDI_SUCCESS;
253 		break;
254 	default:
255 		retval = DDI_FAILURE;
256 	}
257 	return (retval);
258 }
259 
260 static int
261 xenbusdrv_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
262 {
263 	int	error;
264 	int	unit = ddi_get_instance(dip);
265 
266 
267 	switch (cmd) {
268 	case DDI_ATTACH:
269 		break;
270 	case DDI_RESUME:
271 		return (DDI_SUCCESS);
272 	default:
273 		cmn_err(CE_WARN, "xenbus_attach: unknown cmd 0x%x\n", cmd);
274 		return (DDI_FAILURE);
275 	}
276 
277 	/* DDI_ATTACH */
278 
279 	/*
280 	 * only one instance - but we clone using the open routine
281 	 */
282 	if (ddi_get_instance(dip) > 0)
283 		return (DDI_FAILURE);
284 
285 	mutex_init(&xenbusdrv_clone_tab_mutex, NULL, MUTEX_DRIVER,
286 	    NULL);
287 
288 	error = ddi_create_minor_node(dip, "xenbus", S_IFCHR, unit,
289 	    DDI_PSEUDO, NULL);
290 	if (error != DDI_SUCCESS)
291 		goto fail;
292 
293 	/*
294 	 * save dip for getinfo
295 	 */
296 	xenbusdrv_dip = dip;
297 	ddi_report_dev(dip);
298 
299 #ifndef XPV_HVM_DRIVER
300 	if (DOMAIN_IS_INITDOMAIN(xen_info))
301 		xs_dom0_init();
302 #endif
303 
304 	return (DDI_SUCCESS);
305 
306 fail:
307 	(void) xenbusdrv_detach(dip, DDI_DETACH);
308 	return (error);
309 }
310 
311 static int
312 xenbusdrv_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
313 {
314 	/*
315 	 * again, only one instance
316 	 */
317 	if (ddi_get_instance(dip) > 0)
318 		return (DDI_FAILURE);
319 
320 	switch (cmd) {
321 	case DDI_DETACH:
322 		ddi_remove_minor_node(dip, NULL);
323 		mutex_destroy(&xenbusdrv_clone_tab_mutex);
324 		xenbusdrv_dip = NULL;
325 		return (DDI_SUCCESS);
326 	case DDI_SUSPEND:
327 		return (DDI_SUCCESS);
328 	default:
329 		cmn_err(CE_WARN, "xenbus_detach: unknown cmd 0x%x\n", cmd);
330 		return (DDI_FAILURE);
331 	}
332 }
333 
334 /* ARGSUSED */
335 static int
336 xenbusdrv_open(dev_t *devp, int flag, int otyp, cred_t *cr)
337 {
338 	xenbus_dev_t *xbs;
339 	minor_t minor = getminor(*devp);
340 
341 	if (otyp == OTYP_BLK)
342 		return (ENXIO);
343 
344 	/*
345 	 * only allow open on minor = 0 - the clone device
346 	 */
347 	if (minor != 0)
348 		return (ENXIO);
349 
350 	/*
351 	 * find a free slot and grab it
352 	 */
353 	mutex_enter(&xenbusdrv_clone_tab_mutex);
354 	for (minor = 1; minor < XENBUSDRV_NCLONES; minor++) {
355 		if (xenbusdrv_clone_tab[minor] == 0) {
356 			xenbusdrv_clone_tab[minor] = 1;
357 			break;
358 		}
359 	}
360 	mutex_exit(&xenbusdrv_clone_tab_mutex);
361 	if (minor == XENBUSDRV_NCLONES)
362 		return (EAGAIN);
363 
364 	/* Allocate softstate structure */
365 	if (ddi_soft_state_zalloc(xenbusdrv_statep,
366 	    XENBUSDRV_MINOR2INST(minor)) != DDI_SUCCESS) {
367 		mutex_enter(&xenbusdrv_clone_tab_mutex);
368 		xenbusdrv_clone_tab[minor] = 0;
369 		mutex_exit(&xenbusdrv_clone_tab_mutex);
370 		return (EAGAIN);
371 	}
372 	xbs = XENBUSDRV_INST2SOFTS(XENBUSDRV_MINOR2INST(minor));
373 
374 	/* ... and init it */
375 	xbs->dip = xenbusdrv_dip;
376 	mutex_init(&xbs->read_mutex, NULL, MUTEX_DRIVER, NULL);
377 	cv_init(&xbs->read_cv, NULL, CV_DEFAULT, NULL);
378 	list_create(&xbs->transactions, sizeof (struct xenbus_dev_transaction),
379 	    offsetof(struct xenbus_dev_transaction, list));
380 
381 	/* clone driver */
382 	*devp = makedevice(getmajor(*devp), minor);
383 	XENBUSDRV_DBPRINT((CE_NOTE, "Xenbus drv open succeeded, minor=%d",
384 	    minor));
385 
386 	return (0);
387 }
388 
389 /* ARGSUSED */
390 static int
391 xenbusdrv_close(dev_t dev, int flag, int otyp, struct cred *cr)
392 {
393 	xenbus_dev_t *xbs;
394 	minor_t minor = getminor(dev);
395 	struct xenbus_dev_transaction *trans;
396 
397 	xbs = XENBUSDRV_INST2SOFTS(XENBUSDRV_MINOR2INST(minor));
398 	if (xbs == NULL)
399 		return (ENXIO);
400 
401 #ifdef notyet
402 	/*
403 	 * XXPV - would like to be able to notify xenstore down here, but
404 	 * as the daemon is currently written, it doesn't leave the device
405 	 * open after initial setup, so we have no way of knowing if it has
406 	 * gone away.
407 	 */
408 	if (xbs->xenstore_inst)
409 		xs_notify_xenstore_down();
410 #endif
411 	/* free pending transaction */
412 	while (trans = (struct xenbus_dev_transaction *)
413 	    list_head(&xbs->transactions)) {
414 		(void) xenbus_transaction_end(trans->handle, 1);
415 		list_remove(&xbs->transactions, (void *)trans);
416 		kmem_free(trans, sizeof (*trans));
417 	}
418 
419 	mutex_destroy(&xbs->read_mutex);
420 	cv_destroy(&xbs->read_cv);
421 	ddi_soft_state_free(xenbusdrv_statep, XENBUSDRV_MINOR2INST(minor));
422 
423 	/*
424 	 * free clone tab slot
425 	 */
426 	mutex_enter(&xenbusdrv_clone_tab_mutex);
427 	xenbusdrv_clone_tab[minor] = 0;
428 	mutex_exit(&xenbusdrv_clone_tab_mutex);
429 
430 	XENBUSDRV_DBPRINT((CE_NOTE, "Xenbus drv close succeeded, minor=%d",
431 	    minor));
432 
433 	return (0);
434 }
435 
436 /* ARGSUSED */
437 static int
438 xenbusdrv_read(dev_t dev, struct uio *uiop, cred_t *cr)
439 {
440 	xenbus_dev_t *xbs;
441 	size_t len;
442 	int res, ret;
443 	int idx;
444 
445 	XENBUSDRV_DBPRINT((CE_NOTE, "xenbusdrv_read called"));
446 
447 	if (secpolicy_xvm_control(cr))
448 		return (EPERM);
449 
450 	xbs = XENBUSDRV_INST2SOFTS(XENBUSDRV_MINOR2INST(getminor(dev)));
451 
452 	mutex_enter(&xbs->read_mutex);
453 
454 	/* check if we have something to read */
455 	while (xbs->read_prod == xbs->read_cons) {
456 		if (cv_wait_sig(&xbs->read_cv, &xbs->read_mutex) == 0) {
457 			mutex_exit(&xbs->read_mutex);
458 			return (EINTR);
459 		}
460 	}
461 
462 	idx = XENBUSDRV_MASK_READ_IDX(xbs->read_cons);
463 	res = uiop->uio_resid;
464 
465 	len = xbs->read_prod - xbs->read_cons;
466 
467 	if (len > (sizeof (xbs->read_buffer) - idx))
468 		len = sizeof (xbs->read_buffer) - idx;
469 	if (len > res)
470 		len = res;
471 
472 	ret = uiomove(xbs->read_buffer + idx, len, UIO_READ, uiop);
473 	xbs->read_cons += res - uiop->uio_resid;
474 	mutex_exit(&xbs->read_mutex);
475 
476 	return (ret);
477 }
478 
479 /*
480  * prepare data for xenbusdrv_read()
481  */
482 static int
483 xenbusdrv_queue_reply(xenbus_dev_t *xbs, const struct xsd_sockmsg *msg,
484     const char *reply)
485 {
486 	int i;
487 	int remaining;
488 
489 	XENBUSDRV_DBPRINT((CE_NOTE, "xenbusdrv_queue_reply called"));
490 
491 	mutex_enter(&xbs->read_mutex);
492 
493 	remaining = sizeof (xbs->read_buffer) -
494 	    (xbs->read_prod - xbs->read_cons);
495 
496 	if (sizeof (*msg) + msg->len > remaining) {
497 		mutex_exit(&xbs->read_mutex);
498 		return (EOVERFLOW);
499 	}
500 
501 	for (i = 0; i < sizeof (*msg); i++, xbs->read_prod++) {
502 		xbs->read_buffer[XENBUSDRV_MASK_READ_IDX(xbs->read_prod)] =
503 		    ((char *)msg)[i];
504 	}
505 
506 	for (i = 0; i < msg->len; i++, xbs->read_prod++) {
507 		xbs->read_buffer[XENBUSDRV_MASK_READ_IDX(xbs->read_prod)] =
508 		    reply[i];
509 	}
510 
511 	cv_broadcast(&xbs->read_cv);
512 
513 	mutex_exit(&xbs->read_mutex);
514 
515 	XENBUSDRV_DBPRINT((CE_NOTE, "xenbusdrv_queue_reply exited"));
516 
517 	return (0);
518 }
519 
520 /* ARGSUSED */
521 static int
522 xenbusdrv_write(dev_t dev, struct uio *uiop, cred_t *cr)
523 {
524 	xenbus_dev_t *xbs;
525 	struct xenbus_dev_transaction *trans;
526 	void *reply;
527 	size_t len;
528 	int rc = 0;
529 
530 	XENBUSDRV_DBPRINT((CE_NOTE, "xenbusdrv_write called"));
531 
532 	if (secpolicy_xvm_control(cr))
533 		return (EPERM);
534 
535 	xbs = XENBUSDRV_INST2SOFTS(XENBUSDRV_MINOR2INST(getminor(dev)));
536 	len = uiop->uio_resid;
537 
538 	if ((len + xbs->len) > sizeof (xbs->u.buffer)) {
539 		XENBUSDRV_DBPRINT((CE_WARN, "Request is too big"));
540 		rc = EINVAL;
541 		goto out;
542 	}
543 
544 	if (uiomove(xbs->u.buffer + xbs->len, len, UIO_WRITE, uiop) != 0) {
545 		XENBUSDRV_DBPRINT((CE_WARN, "Uiomove failed"));
546 		rc = EFAULT;
547 		goto out;
548 	}
549 
550 	xbs->len += len;
551 
552 	if (xbs->len < (sizeof (xbs->u.msg)) ||
553 	    xbs->len < (sizeof (xbs->u.msg) + xbs->u.msg.len)) {
554 		XENBUSDRV_DBPRINT((CE_NOTE, "Partial request"));
555 		return (0);
556 	}
557 
558 	switch (xbs->u.msg.type) {
559 	case XS_TRANSACTION_START:
560 	case XS_TRANSACTION_END:
561 	case XS_DIRECTORY:
562 	case XS_READ:
563 	case XS_GET_PERMS:
564 	case XS_RELEASE:
565 	case XS_GET_DOMAIN_PATH:
566 	case XS_WRITE:
567 	case XS_MKDIR:
568 	case XS_RM:
569 	case XS_SET_PERMS:
570 		/* send the request to xenstore and get feedback */
571 		rc = xenbus_dev_request_and_reply(&xbs->u.msg, &reply);
572 		if (rc) {
573 			XENBUSDRV_DBPRINT((CE_WARN,
574 			    "xenbus_dev_request_and_reply failed"));
575 			goto out;
576 		}
577 
578 		/* handle transaction start/end */
579 		if (xbs->u.msg.type == XS_TRANSACTION_START) {
580 			trans = kmem_alloc(sizeof (*trans), KM_SLEEP);
581 			(void) ddi_strtoul((char *)reply, NULL, 0,
582 			    (unsigned long *)&trans->handle);
583 			list_insert_tail(&xbs->transactions, (void *)trans);
584 		} else if (xbs->u.msg.type == XS_TRANSACTION_END) {
585 			/* try to find out the ending transaction */
586 			for (trans = (struct xenbus_dev_transaction *)
587 			    list_head(&xbs->transactions); trans;
588 			    trans = (struct xenbus_dev_transaction *)
589 			    list_next(&xbs->transactions, (void *)trans))
590 				if (trans->handle ==
591 				    (xenbus_transaction_t)
592 				    xbs->u.msg.tx_id)
593 					break;
594 			ASSERT(trans);
595 			/* free it, if we find it */
596 			list_remove(&xbs->transactions, (void *)trans);
597 			kmem_free(trans, sizeof (*trans));
598 		}
599 
600 		/* prepare data for xenbusdrv_read() to get */
601 		rc = xenbusdrv_queue_reply(xbs, &xbs->u.msg, reply);
602 
603 		kmem_free(reply, xbs->u.msg.len + 1);
604 		break;
605 	default:
606 		rc = EINVAL;
607 	}
608 
609 out:
610 	xbs->len = 0;
611 	return (rc);
612 }
613 
614 /*ARGSUSED*/
615 static int
616 xenbusdrv_devmap(dev_t dev, devmap_cookie_t dhp, offset_t off, size_t len,
617     size_t *maplen, uint_t model)
618 {
619 	xenbus_dev_t *xbs;
620 	int err;
621 
622 	xbs = XENBUSDRV_INST2SOFTS(XENBUSDRV_MINOR2INST(getminor(dev)));
623 
624 	if (off != 0 || len != PAGESIZE)
625 		return (-1);
626 
627 	if (!DOMAIN_IS_INITDOMAIN(xen_info))
628 		return (-1);
629 
630 	err = devmap_umem_setup(dhp, xbs->dip, NULL, xb_xenstore_cookie(),
631 	    0, PAGESIZE, PROT_READ | PROT_WRITE | PROT_USER, 0, NULL);
632 
633 	if (err)
634 		return (err);
635 
636 	*maplen = PAGESIZE;
637 
638 	return (0);
639 }
640 
641 static int
642 xenbusdrv_segmap(dev_t dev, off_t off, ddi_as_handle_t as, caddr_t *addrp,
643     off_t len, uint_t prot, uint_t maxprot, uint_t flags, cred_t *cr)
644 {
645 
646 	if (secpolicy_xvm_control(cr))
647 		return (EPERM);
648 
649 	return (ddi_devmap_segmap(dev, off, as, addrp, len, prot,
650 	    maxprot, flags, cr));
651 }
652 
653 /*ARGSUSED*/
654 static int
655 xenbusdrv_ioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *cr,
656     int *rvalp)
657 {
658 	xenbus_dev_t *xbs;
659 
660 	if (secpolicy_xvm_control(cr))
661 		return (EPERM);
662 
663 	xbs = XENBUSDRV_INST2SOFTS(XENBUSDRV_MINOR2INST(getminor(dev)));
664 	switch (cmd) {
665 	case IOCTL_XENBUS_XENSTORE_EVTCHN:
666 		*rvalp = xen_info->store_evtchn;
667 		break;
668 	case IOCTL_XENBUS_NOTIFY_UP:
669 		xs_notify_xenstore_up();
670 		xbs->xenstore_inst = 1;
671 		break;
672 	default:
673 		return (EINVAL);
674 	}
675 
676 	return (0);
677 }
678