1 /*
2 * Copyright (c) 2014 Roger Pau Monné <roger.pau@citrix.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 #include <sys/types.h>
29 #include <sys/cdefs.h>
30 #include <sys/errno.h>
31 #include <sys/uio.h>
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/proc.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/conf.h>
38 #include <sys/module.h>
39
40 #include <xen/xen-os.h>
41
42 #include <xen/hypervisor.h>
43 #include <xen/xenstore/xenstorevar.h>
44
45 #include <vm/vm.h>
46 #include <vm/pmap.h>
47
48 #define XSD_READ_SIZE 20
49
50 static int xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag);
51 static int xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset,
52 vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr);
53
54 static struct cdevsw xsd_dev_cdevsw = {
55 .d_version = D_VERSION,
56 .d_read = xsd_dev_read,
57 .d_mmap = xsd_dev_mmap,
58 .d_name = "xsd_dev",
59 };
60
61 static int
xsd_dev_read(struct cdev * dev,struct uio * uio,int ioflag)62 xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag)
63 {
64 char evtchn[XSD_READ_SIZE];
65 int error, len;
66
67 len = snprintf(evtchn, sizeof(evtchn), "%u", xs_evtchn());
68 if (len < 0 || len > uio->uio_resid)
69 return (EINVAL);
70
71 error = uiomove(evtchn, len, uio);
72 if (error)
73 return (error);
74
75 return (0);
76 }
77
78 static int
xsd_dev_mmap(struct cdev * dev,vm_ooffset_t offset,vm_paddr_t * paddr,int nprot,vm_memattr_t * memattr)79 xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
80 int nprot, vm_memattr_t *memattr)
81 {
82
83 if (offset != 0)
84 return (EINVAL);
85
86 *paddr = xs_address();
87
88 return (0);
89 }
90
91 /*------------------ Private Device Attachment Functions --------------------*/
92 /**
93 * \brief Identify instances of this device type in the system.
94 *
95 * \param driver The driver performing this identify action.
96 * \param parent The NewBus parent device for any devices this method adds.
97 */
98 static void
xsd_dev_identify(driver_t * driver __unused,device_t parent)99 xsd_dev_identify(driver_t *driver __unused, device_t parent)
100 {
101
102 if (!xen_domain() || xs_initialized())
103 return;
104
105 /*
106 * Only attach if xenstore is not available, because we are the
107 * domain that's supposed to run it.
108 */
109 BUS_ADD_CHILD(parent, 0, driver->name, 0);
110 }
111
112 /**
113 * \brief Probe for the existence of the Xenstored device
114 *
115 * \param dev NewBus device_t for this instance.
116 *
117 * \return Always returns 0 indicating success.
118 */
119 static int
xsd_dev_probe(device_t dev)120 xsd_dev_probe(device_t dev)
121 {
122
123 device_set_desc(dev, "Xenstored user-space device");
124 return (BUS_PROBE_NOWILDCARD);
125 }
126
127 /**
128 * \brief Attach the Xenstored device.
129 *
130 * \param dev NewBus device_t for this instance.
131 *
132 * \return On success, 0. Otherwise an errno value indicating the
133 * type of failure.
134 */
135 static int
xsd_dev_attach(device_t dev)136 xsd_dev_attach(device_t dev)
137 {
138 struct cdev *xsd_cdev;
139
140 xsd_cdev = make_dev(&xsd_dev_cdevsw, 0, UID_ROOT, GID_WHEEL, 0400,
141 "xen/xenstored");
142 if (xsd_cdev == NULL)
143 return (EINVAL);
144
145 return (0);
146 }
147
148 /*-------------------- Private Device Attachment Data -----------------------*/
149 static device_method_t xsd_dev_methods[] = {
150 /* Device interface */
151 DEVMETHOD(device_identify, xsd_dev_identify),
152 DEVMETHOD(device_probe, xsd_dev_probe),
153 DEVMETHOD(device_attach, xsd_dev_attach),
154
155 DEVMETHOD_END
156 };
157
158 DEFINE_CLASS_0(xsd_dev, xsd_dev_driver, xsd_dev_methods, 0);
159
160 DRIVER_MODULE(xsd_dev, xenpv, xsd_dev_driver, NULL, NULL);
161