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/types.h>
28 #include <sys/cdefs.h>
29 #include <sys/errno.h>
30 #include <sys/uio.h>
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/proc.h>
34 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/conf.h>
37 #include <sys/module.h>
38
39 #include <xen/xen-os.h>
40
41 #include <xen/hypervisor.h>
42 #include <xen/xenstore/xenstorevar.h>
43
44 #include <vm/vm.h>
45 #include <vm/pmap.h>
46
47 #define XSD_READ_SIZE 20
48
49 static int xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag);
50 static int xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset,
51 vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr);
52
53 static struct cdevsw xsd_dev_cdevsw = {
54 .d_version = D_VERSION,
55 .d_read = xsd_dev_read,
56 .d_mmap = xsd_dev_mmap,
57 .d_name = "xsd_dev",
58 };
59
60 static int
xsd_dev_read(struct cdev * dev,struct uio * uio,int ioflag)61 xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag)
62 {
63 char evtchn[XSD_READ_SIZE];
64 int error, len;
65
66 len = snprintf(evtchn, sizeof(evtchn), "%u", xs_evtchn());
67 if (len < 0 || len > uio->uio_resid)
68 return (EINVAL);
69
70 error = uiomove(evtchn, len, uio);
71 if (error)
72 return (error);
73
74 return (0);
75 }
76
77 static int
xsd_dev_mmap(struct cdev * dev,vm_ooffset_t offset,vm_paddr_t * paddr,int nprot,vm_memattr_t * memattr)78 xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
79 int nprot, vm_memattr_t *memattr)
80 {
81
82 if (offset != 0)
83 return (EINVAL);
84
85 *paddr = xs_address();
86
87 return (0);
88 }
89
90 /*------------------ Private Device Attachment Functions --------------------*/
91 /**
92 * \brief Identify instances of this device type in the system.
93 *
94 * \param driver The driver performing this identify action.
95 * \param parent The NewBus parent device for any devices this method adds.
96 */
97 static void
xsd_dev_identify(driver_t * driver,device_t parent)98 xsd_dev_identify(driver_t *driver, device_t parent)
99 {
100
101 if (!xen_domain() || xs_initialized())
102 return;
103
104 /*
105 * Only attach if xenstore is not available, because we are the
106 * domain that's supposed to run it.
107 */
108 BUS_ADD_CHILD(parent, 0, driver->name, 0);
109 }
110
111 /**
112 * \brief Probe for the existence of the Xenstored device
113 *
114 * \param dev NewBus device_t for this instance.
115 *
116 * \return Always returns 0 indicating success.
117 */
118 static int
xsd_dev_probe(device_t dev)119 xsd_dev_probe(device_t dev)
120 {
121
122 device_set_desc(dev, "Xenstored user-space device");
123 return (BUS_PROBE_NOWILDCARD);
124 }
125
126 /**
127 * \brief Attach the Xenstored device.
128 *
129 * \param dev NewBus device_t for this instance.
130 *
131 * \return On success, 0. Otherwise an errno value indicating the
132 * type of failure.
133 */
134 static int
xsd_dev_attach(device_t dev)135 xsd_dev_attach(device_t dev)
136 {
137 struct cdev *xsd_cdev;
138
139 xsd_cdev = make_dev(&xsd_dev_cdevsw, 0, UID_ROOT, GID_WHEEL, 0400,
140 "xen/xenstored");
141 if (xsd_cdev == NULL)
142 return (EINVAL);
143
144 return (0);
145 }
146
147 /*-------------------- Private Device Attachment Data -----------------------*/
148 static device_method_t xsd_dev_methods[] = {
149 /* Device interface */
150 DEVMETHOD(device_identify, xsd_dev_identify),
151 DEVMETHOD(device_probe, xsd_dev_probe),
152 DEVMETHOD(device_attach, xsd_dev_attach),
153
154 DEVMETHOD_END
155 };
156
157 DEFINE_CLASS_0(xsd_dev, xsd_dev_driver, xsd_dev_methods, 0);
158
159 DRIVER_MODULE(xsd_dev, xenpv, xsd_dev_driver, NULL, NULL);
160