1/*
2 * Copyright (c) 2014 Roger Pau Monn�� <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
49static int xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag);
50static int xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset,
51    vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr);
52
53static 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
60static int
61xsd_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
77static int
78xsd_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 */
97static void
98xsd_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 */
118static int
119xsd_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 */
134static int
135xsd_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  -----------------------*/
148static 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
157DEFINE_CLASS_0(xsd_dev, xsd_dev_driver, xsd_dev_methods, 0);
158
159DRIVER_MODULE(xsd_dev, xenpv, xsd_dev_driver, NULL, NULL);
160