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/cdefs.h>
28__FBSDID("$FreeBSD$");
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
52static int xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag);
53static int xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset,
54    vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr);
55
56static struct cdevsw xsd_dev_cdevsw = {
57	.d_version = D_VERSION,
58	.d_read = xsd_dev_read,
59	.d_mmap = xsd_dev_mmap,
60	.d_name = "xsd_dev",
61};
62
63static int
64xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag)
65{
66	char evtchn[XSD_READ_SIZE];
67	int error, len;
68
69	len = snprintf(evtchn, sizeof(evtchn), "%u", xs_evtchn());
70	if (len < 0 || len > uio->uio_resid)
71		return (EINVAL);
72
73	error = uiomove(evtchn, len, uio);
74	if (error)
75		return (error);
76
77	return (0);
78}
79
80static int
81xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
82    int nprot, vm_memattr_t *memattr)
83{
84
85	if (offset != 0)
86		return (EINVAL);
87
88	*paddr = xs_address();
89
90	return (0);
91}
92
93/*------------------ Private Device Attachment Functions  --------------------*/
94/**
95 * \brief Identify instances of this device type in the system.
96 *
97 * \param driver  The driver performing this identify action.
98 * \param parent  The NewBus parent device for any devices this method adds.
99 */
100static void
101xsd_dev_identify(driver_t *driver __unused, device_t parent)
102{
103
104	if (!xen_domain() || xs_initialized())
105		return;
106
107	/*
108	 * Only attach if xenstore is not available, because we are the
109	 * domain that's supposed to run it.
110	 */
111	BUS_ADD_CHILD(parent, 0, driver->name, 0);
112}
113
114/**
115 * \brief Probe for the existence of the Xenstored device
116 *
117 * \param dev  NewBus device_t for this instance.
118 *
119 * \return  Always returns 0 indicating success.
120 */
121static int
122xsd_dev_probe(device_t dev)
123{
124
125	device_set_desc(dev, "Xenstored user-space device");
126	return (BUS_PROBE_NOWILDCARD);
127}
128
129/**
130 * \brief Attach the Xenstored device.
131 *
132 * \param dev  NewBus device_t for this instance.
133 *
134 * \return  On success, 0. Otherwise an errno value indicating the
135 *          type of failure.
136 */
137static int
138xsd_dev_attach(device_t dev)
139{
140	struct cdev *xsd_cdev;
141
142	xsd_cdev = make_dev(&xsd_dev_cdevsw, 0, UID_ROOT, GID_WHEEL, 0400,
143	    "xen/xenstored");
144	if (xsd_cdev == NULL)
145		return (EINVAL);
146
147	return (0);
148}
149
150/*-------------------- Private Device Attachment Data  -----------------------*/
151static device_method_t xsd_dev_methods[] = {
152	/* Device interface */
153	DEVMETHOD(device_identify,	xsd_dev_identify),
154	DEVMETHOD(device_probe,         xsd_dev_probe),
155	DEVMETHOD(device_attach,        xsd_dev_attach),
156
157	DEVMETHOD_END
158};
159
160DEFINE_CLASS_0(xsd_dev, xsd_dev_driver, xsd_dev_methods, 0);
161devclass_t xsd_dev_devclass;
162
163DRIVER_MODULE(xsd_dev, xenpv, xsd_dev_driver, xsd_dev_devclass,
164    NULL, NULL);
165