xref: /titanic_52/usr/src/uts/i86xpv/io/balloon_drv.c (revision f38cb554a534c6df738be3f4d23327e69888e634)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 
28 /*
29  * A simple wrapper around the balloon kernel thread to allow userland
30  * programs access to the balloon status.
31  */
32 
33 #include <sys/types.h>
34 #include <sys/file.h>
35 #include <sys/errno.h>
36 #include <sys/open.h>
37 #include <sys/cred.h>
38 #include <sys/conf.h>
39 #include <sys/stat.h>
40 #include <sys/modctl.h>
41 #include <sys/ddi.h>
42 #include <sys/sunddi.h>
43 #include <sys/hypervisor.h>
44 #include <sys/sysmacros.h>
45 #include <sys/balloon_impl.h>
46 
47 static dev_info_t *balloon_devi;
48 
49 /*ARGSUSED*/
50 static int
51 balloon_getinfo(dev_info_t *devi, ddi_info_cmd_t cmd, void *arg, void **result)
52 {
53 	if (getminor((dev_t)arg) != BALLOON_MINOR)
54 		return (DDI_FAILURE);
55 
56 	switch (cmd) {
57 	case DDI_INFO_DEVT2DEVINFO:
58 		*result = balloon_devi;
59 		break;
60 	case DDI_INFO_DEVT2INSTANCE:
61 		*result = 0;
62 		break;
63 	default:
64 		return (DDI_FAILURE);
65 	}
66 
67 	return (DDI_SUCCESS);
68 }
69 
70 static int
71 balloon_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
72 {
73 	if (cmd != DDI_ATTACH)
74 		return (DDI_FAILURE);
75 
76 	if (ddi_create_minor_node(devi, ddi_get_name(devi), S_IFCHR,
77 	    ddi_get_instance(devi), DDI_PSEUDO, 0) != DDI_SUCCESS)
78 		return (DDI_FAILURE);
79 
80 	balloon_devi = devi;
81 	ddi_report_dev(devi);
82 	return (DDI_SUCCESS);
83 }
84 
85 static int
86 balloon_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
87 {
88 	if (cmd != DDI_DETACH)
89 		return (DDI_FAILURE);
90 	ddi_remove_minor_node(devi, NULL);
91 	balloon_devi = NULL;
92 	return (DDI_SUCCESS);
93 }
94 
95 /*ARGSUSED1*/
96 static int
97 balloon_open(dev_t *dev, int flag, int otyp, cred_t *cr)
98 {
99 	return (getminor(*dev) == BALLOON_MINOR ? 0 : ENXIO);
100 }
101 
102 /*
103  * When asked for one of the balloon values, we simply query the balloon thread.
104  */
105 /*ARGSUSED*/
106 static int
107 balloon_ioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *cr,
108     int *rval_p)
109 {
110 	int rval = 0;
111 	size_t value;
112 
113 	switch (cmd) {
114 	case BLN_IOCTL_CURRENT:
115 	case BLN_IOCTL_TARGET:
116 	case BLN_IOCTL_LOW:
117 	case BLN_IOCTL_HIGH:
118 	case BLN_IOCTL_LIMIT:
119 		value = balloon_values(cmd);
120 		if (ddi_copyout((void *)&value, (void *)arg, sizeof (value),
121 		    mode))
122 			return (EFAULT);
123 		break;
124 	default:
125 		rval = EINVAL;
126 		break;
127 	}
128 	return (rval);
129 }
130 
131 static struct cb_ops balloon_cb_ops = {
132 	balloon_open,
133 	nulldev,	/* close */
134 	nodev,		/* strategy */
135 	nodev,		/* print */
136 	nodev,		/* dump */
137 	nodev,		/* read */
138 	nodev,		/* write */
139 	balloon_ioctl,	/* ioctl */
140 	nodev,		/* devmap */
141 	nodev,		/* mmap */
142 	nodev,		/* segmap */
143 	nochpoll,	/* poll */
144 	ddi_prop_op,
145 	NULL,
146 	D_64BIT | D_MP,
147 	CB_REV,
148 	NULL,
149 	NULL
150 };
151 
152 static struct dev_ops balloon_dv_ops = {
153 	DEVO_REV,
154 	0,
155 	balloon_getinfo,
156 	nulldev,		/* identify */
157 	nulldev,		/* probe */
158 	balloon_attach,
159 	balloon_detach,
160 	nodev,			/* reset */
161 	&balloon_cb_ops,
162 	NULL,			/* struct bus_ops */
163 	NULL,			/* power */
164 	ddi_quiesce_not_needed,		/* quiesce */
165 };
166 
167 static struct modldrv modldrv = {
168 	&mod_driverops,
169 	"balloon driver",
170 	&balloon_dv_ops
171 };
172 
173 static struct modlinkage modl = {
174 	MODREV_1,
175 	{
176 		(void *)&modldrv,
177 		NULL		/* null termination */
178 	}
179 };
180 
181 int
182 _init(void)
183 {
184 	return (mod_install(&modl));
185 }
186 
187 int
188 _fini(void)
189 {
190 	return (mod_remove(&modl));
191 }
192 
193 int
194 _info(struct modinfo *modinfo)
195 {
196 	return (mod_info(&modl, modinfo));
197 }
198