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 __FBSDID("$FreeBSD: stable/12/sys/dev/xen/xenstore/xenstored_dev.c 336470 2018-07-19 07:54:45Z royger $");
29
30 #include <sys/types.h>
31 #include <sys/cdefs.h>
32 #include <sys/errno.h>
33 #include <sys/uio.h>
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/proc.h>
37 #include <sys/kernel.h>
38 #include <sys/malloc.h>
39 #include <sys/conf.h>
40 #include <sys/module.h>
41
42 #include <xen/xen-os.h>
43
44 #include <xen/hypervisor.h>
45 #include <xen/xenstore/xenstorevar.h>
46
47 #include <vm/vm.h>
48 #include <vm/pmap.h>
49
50 #define XSD_READ_SIZE 20
51
52 static int xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag);
53 static int xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset,
54 vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr);
55
56
57 static struct cdevsw xsd_dev_cdevsw = {
58 .d_version = D_VERSION,
59 .d_read = xsd_dev_read,
60 .d_mmap = xsd_dev_mmap,
61 .d_name = "xsd_dev",
62 };
63
64 static int
xsd_dev_read(struct cdev * dev,struct uio * uio,int ioflag)65 xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag)
66 {
67 char evtchn[XSD_READ_SIZE];
68 int error, len;
69
70 len = snprintf(evtchn, sizeof(evtchn), "%u", xs_evtchn());
71 if (len < 0 || len > uio->uio_resid)
72 return (EINVAL);
73
74 error = uiomove(evtchn, len, uio);
75 if (error)
76 return (error);
77
78 return (0);
79 }
80
81 static int
xsd_dev_mmap(struct cdev * dev,vm_ooffset_t offset,vm_paddr_t * paddr,int nprot,vm_memattr_t * memattr)82 xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
83 int nprot, vm_memattr_t *memattr)
84 {
85
86 if (offset != 0)
87 return (EINVAL);
88
89 *paddr = xs_address();
90
91 return (0);
92 }
93
94 /*------------------ Private Device Attachment Functions --------------------*/
95 /**
96 * \brief Identify instances of this device type in the system.
97 *
98 * \param driver The driver performing this identify action.
99 * \param parent The NewBus parent device for any devices this method adds.
100 */
101 static void
xsd_dev_identify(driver_t * driver __unused,device_t parent)102 xsd_dev_identify(driver_t *driver __unused, device_t parent)
103 {
104
105 if (!xen_domain() || xs_initialized())
106 return;
107
108 /*
109 * Only attach if xenstore is not available, because we are the
110 * domain that's supposed to run it.
111 */
112 BUS_ADD_CHILD(parent, 0, driver->name, 0);
113 }
114
115 /**
116 * \brief Probe for the existence of the Xenstored device
117 *
118 * \param dev NewBus device_t for this instance.
119 *
120 * \return Always returns 0 indicating success.
121 */
122 static int
xsd_dev_probe(device_t dev)123 xsd_dev_probe(device_t dev)
124 {
125
126 device_set_desc(dev, "Xenstored user-space device");
127 return (BUS_PROBE_NOWILDCARD);
128 }
129
130 /**
131 * \brief Attach the Xenstored device.
132 *
133 * \param dev NewBus device_t for this instance.
134 *
135 * \return On success, 0. Otherwise an errno value indicating the
136 * type of failure.
137 */
138 static int
xsd_dev_attach(device_t dev)139 xsd_dev_attach(device_t dev)
140 {
141 struct cdev *xsd_cdev;
142
143 xsd_cdev = make_dev(&xsd_dev_cdevsw, 0, UID_ROOT, GID_WHEEL, 0400,
144 "xen/xenstored");
145 if (xsd_cdev == NULL)
146 return (EINVAL);
147
148 return (0);
149 }
150
151 /*-------------------- Private Device Attachment Data -----------------------*/
152 static device_method_t xsd_dev_methods[] = {
153 /* Device interface */
154 DEVMETHOD(device_identify, xsd_dev_identify),
155 DEVMETHOD(device_probe, xsd_dev_probe),
156 DEVMETHOD(device_attach, xsd_dev_attach),
157
158 DEVMETHOD_END
159 };
160
161 DEFINE_CLASS_0(xsd_dev, xsd_dev_driver, xsd_dev_methods, 0);
162 devclass_t xsd_dev_devclass;
163
164 DRIVER_MODULE(xsd_dev, xenpv, xsd_dev_driver, xsd_dev_devclass,
165 NULL, NULL);
166