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: releng/11.0/sys/dev/xen/xenstore/xenstored_dev.c 272319 2014-09-30 17:37:26Z 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#include <xen/xenstore/xenstore_internal.h>
47
48#include <vm/vm.h>
49#include <vm/pmap.h>
50
51#define XSD_READ_SIZE		20
52
53static int xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag);
54static int xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset,
55    vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr);
56
57
58static struct cdevsw xsd_dev_cdevsw = {
59	.d_version = D_VERSION,
60	.d_read = xsd_dev_read,
61	.d_mmap = xsd_dev_mmap,
62	.d_name = "xsd_dev",
63};
64
65static int
66xsd_dev_read(struct cdev *dev, struct uio *uio, int ioflag)
67{
68	char evtchn[XSD_READ_SIZE];
69	int error, len;
70
71	len = snprintf(evtchn, sizeof(evtchn), "%u",
72	    HYPERVISOR_start_info->store_evtchn);
73	if (len < 0 || len > uio->uio_resid)
74		return (EINVAL);
75
76	error = uiomove(evtchn, len, uio);
77	if (error)
78		return (error);
79
80	return (0);
81}
82
83static int
84xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
85    int nprot, vm_memattr_t *memattr)
86{
87
88	if (offset != 0)
89		return (EINVAL);
90
91	*paddr = pmap_kextract((vm_offset_t)xen_store);
92
93	return (0);
94}
95
96/*------------------ Private Device Attachment Functions  --------------------*/
97/**
98 * \brief Identify instances of this device type in the system.
99 *
100 * \param driver  The driver performing this identify action.
101 * \param parent  The NewBus parent device for any devices this method adds.
102 */
103static void
104xsd_dev_identify(driver_t *driver __unused, device_t parent)
105{
106
107	if (!xen_pv_domain())
108		return;
109	if (HYPERVISOR_start_info->store_mfn != 0)
110		return;
111
112	/*
113	 * Only attach if xenstore is not available, because we are the
114	 * domain that's supposed to run it.
115	 */
116	BUS_ADD_CHILD(parent, 0, driver->name, 0);
117}
118
119/**
120 * \brief Probe for the existence of the Xenstored device
121 *
122 * \param dev  NewBus device_t for this instance.
123 *
124 * \return  Always returns 0 indicating success.
125 */
126static int
127xsd_dev_probe(device_t dev)
128{
129
130	device_set_desc(dev, "Xenstored user-space device");
131	return (BUS_PROBE_NOWILDCARD);
132}
133
134/**
135 * \brief Attach the Xenstored device.
136 *
137 * \param dev  NewBus device_t for this instance.
138 *
139 * \return  On success, 0. Otherwise an errno value indicating the
140 *          type of failure.
141 */
142static int
143xsd_dev_attach(device_t dev)
144{
145	struct cdev *xsd_cdev;
146
147	xsd_cdev = make_dev(&xsd_dev_cdevsw, 0, UID_ROOT, GID_WHEEL, 0400,
148	    "xen/xenstored");
149	if (xsd_cdev == NULL)
150		return (EINVAL);
151
152	return (0);
153}
154
155/*-------------------- Private Device Attachment Data  -----------------------*/
156static device_method_t xsd_dev_methods[] = {
157	/* Device interface */
158	DEVMETHOD(device_identify,	xsd_dev_identify),
159	DEVMETHOD(device_probe,         xsd_dev_probe),
160	DEVMETHOD(device_attach,        xsd_dev_attach),
161
162	DEVMETHOD_END
163};
164
165DEFINE_CLASS_0(xsd_dev, xsd_dev_driver, xsd_dev_methods, 0);
166devclass_t xsd_dev_devclass;
167
168DRIVER_MODULE(xsd_dev, xenpv, xsd_dev_driver, xsd_dev_devclass,
169    NULL, NULL);
170