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 2009 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * Talks to Xen Store to figure out what devices we have.
29 *
30 * Copyright (C) 2005 Rusty Russell, IBM Corporation
31 * Copyright (C) 2005 Mike Wray, Hewlett-Packard
32 * Copyright (C) 2005 XenSource Ltd
33 *
34 * This file may be distributed separately from the Linux kernel, or
35 * incorporated into other software packages, subject to the following license:
36 *
37 * Permission is hereby granted, free of charge, to any person obtaining a copy
38 * of this source file (the "Software"), to deal in the Software without
39 * restriction, including without limitation the rights to use, copy, modify,
40 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
41 * and to permit persons to whom the Software is furnished to do so, subject to
42 * the following conditions:
43 *
44 * The above copyright notice and this permission notice shall be included in
45 * all copies or substantial portions of the Software.
46 *
47 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
48 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
49 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
50 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
51 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
52 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
53 * IN THE SOFTWARE.
54 */
55
56 #ifdef XPV_HVM_DRIVER
57 #include <sys/xpv_support.h>
58 #endif
59 #include <sys/hypervisor.h>
60 #include <xen/sys/xenbus_impl.h>
61 #include <xen/sys/xenbus_comms.h>
62 #include <xen/public/io/xs_wire.h>
63
64 static int
read_otherend_details(struct xenbus_device * xendev,char * id_node,char * path_node)65 read_otherend_details(struct xenbus_device *xendev,
66 char *id_node, char *path_node)
67 {
68 int err = xenbus_gather(XBT_NULL, xendev->nodename,
69 id_node, "%i", &xendev->otherend_id, path_node, NULL,
70 &xendev->otherend, NULL);
71 if (err) {
72 xenbus_dev_fatal(xendev, err,
73 "reading other end details from %s", xendev->nodename);
74 return (err);
75 }
76 if (strlen(xendev->otherend) == 0 ||
77 !xenbus_exists_dir(xendev->otherend, "")) {
78 xenbus_dev_fatal(xendev, X_ENOENT, "missing other end from %s",
79 xendev->nodename);
80 kmem_free((void *)xendev->otherend,
81 strlen(xendev->otherend) + 1);
82 xendev->otherend = NULL;
83 return (X_ENOENT);
84 }
85
86 return (0);
87 }
88
89
90 static int
read_backend_details(struct xenbus_device * xendev)91 read_backend_details(struct xenbus_device *xendev)
92 {
93 return (read_otherend_details(xendev, "backend-id", "backend"));
94 }
95
96
97 static int
read_frontend_details(struct xenbus_device * xendev)98 read_frontend_details(struct xenbus_device *xendev)
99 {
100 return (read_otherend_details(xendev, "frontend-id", "frontend"));
101 }
102
103
104 static void
free_otherend_details(struct xenbus_device * dev)105 free_otherend_details(struct xenbus_device *dev)
106 {
107 if (dev->otherend != NULL) {
108 kmem_free((void *)dev->otherend, strlen(dev->otherend) + 1);
109 dev->otherend = NULL;
110 }
111 }
112
113
114 static void
free_otherend_watch(struct xenbus_device * dev)115 free_otherend_watch(struct xenbus_device *dev)
116 {
117 if (dev->otherend_watch.node) {
118 unregister_xenbus_watch(&dev->otherend_watch);
119 kmem_free((void *)dev->otherend_watch.node,
120 strlen(dev->otherend_watch.node) + 1);
121 dev->otherend_watch.node = NULL;
122 }
123 }
124
125
126 /*ARGSUSED2*/
127 static void
otherend_changed(struct xenbus_watch * watch,const char ** vec,unsigned int len)128 otherend_changed(struct xenbus_watch *watch, const char **vec, unsigned int len)
129 {
130 struct xenbus_device *dev = watch->dev;
131 XenbusState state;
132
133 /*
134 * Protect us against watches firing on old details when the otherend
135 * details change, say immediately after a resume.
136 */
137 if (!dev->otherend ||
138 strncmp(dev->otherend, vec[XS_WATCH_PATH], strlen(dev->otherend))) {
139 #if 0
140 printf("Ignoring watch at %s", vec[XS_WATCH_PATH]);
141 #endif
142 return;
143 }
144
145 state = xenbus_read_driver_state(dev->otherend);
146
147 #if 0
148 printf("state is %d, %s, %s",
149 state, dev->otherend_watch.node, vec[XS_WATCH_PATH]);
150 #endif
151 if (dev->otherend_changed)
152 dev->otherend_changed(dev, state);
153 }
154
155
156 int
talk_to_otherend(struct xenbus_device * dev)157 talk_to_otherend(struct xenbus_device *dev)
158 {
159 int err;
160
161 free_otherend_watch(dev);
162 free_otherend_details(dev);
163
164 if (dev->frontend)
165 err = read_backend_details(dev);
166 else
167 err = read_frontend_details(dev);
168 if (err)
169 return (err);
170
171 dev->otherend_watch.dev = dev;
172 return (xenbus_watch_path2(dev, dev->otherend, "state",
173 &dev->otherend_watch, otherend_changed));
174 }
175
176
177 /*
178 * Local variables:
179 * c-file-style: "solaris"
180 * indent-tabs-mode: t
181 * c-indent-level: 8
182 * c-basic-offset: 8
183 * tab-width: 8
184 * End:
185 */
186