1 /* hvapi.c: Hypervisor API management.
2 *
3 * Copyright (C) 2007 David S. Miller <davem@davemloft.net>
4 */
5 #include <linux/kernel.h>
6 #include <linux/module.h>
7 #include <linux/init.h>
8 #include <linux/slab.h>
9
10 #include <asm/hypervisor.h>
11 #include <asm/oplib.h>
12
13 /* If the hypervisor indicates that the API setting
14 * calls are unsupported, by returning HV_EBADTRAP or
15 * HV_ENOTSUPPORTED, we assume that API groups with the
16 * PRE_API flag set are major 1 minor 0.
17 */
18 struct api_info {
19 unsigned long group;
20 unsigned long major;
21 unsigned long minor;
22 unsigned int refcnt;
23 unsigned int flags;
24 #define FLAG_PRE_API 0x00000001
25 };
26
27 static struct api_info api_table[] = {
28 { .group = HV_GRP_SUN4V, .flags = FLAG_PRE_API },
29 { .group = HV_GRP_CORE, .flags = FLAG_PRE_API },
30 { .group = HV_GRP_INTR, },
31 { .group = HV_GRP_SOFT_STATE, },
32 { .group = HV_GRP_PCI, .flags = FLAG_PRE_API },
33 { .group = HV_GRP_LDOM, },
34 { .group = HV_GRP_SVC_CHAN, .flags = FLAG_PRE_API },
35 { .group = HV_GRP_NCS, .flags = FLAG_PRE_API },
36 { .group = HV_GRP_RNG, },
37 { .group = HV_GRP_NIAG_PERF, .flags = FLAG_PRE_API },
38 { .group = HV_GRP_FIRE_PERF, },
39 { .group = HV_GRP_N2_CPU, },
40 { .group = HV_GRP_NIU, },
41 { .group = HV_GRP_VF_CPU, },
42 { .group = HV_GRP_DIAG, .flags = FLAG_PRE_API },
43 };
44
45 static DEFINE_SPINLOCK(hvapi_lock);
46
__get_info(unsigned long group)47 static struct api_info *__get_info(unsigned long group)
48 {
49 int i;
50
51 for (i = 0; i < ARRAY_SIZE(api_table); i++) {
52 if (api_table[i].group == group)
53 return &api_table[i];
54 }
55 return NULL;
56 }
57
__get_ref(struct api_info * p)58 static void __get_ref(struct api_info *p)
59 {
60 p->refcnt++;
61 }
62
__put_ref(struct api_info * p)63 static void __put_ref(struct api_info *p)
64 {
65 if (--p->refcnt == 0) {
66 unsigned long ignore;
67
68 sun4v_set_version(p->group, 0, 0, &ignore);
69 p->major = p->minor = 0;
70 }
71 }
72
73 /* Register a hypervisor API specification. It indicates the
74 * API group and desired major+minor.
75 *
76 * If an existing API registration exists '0' (success) will
77 * be returned if it is compatible with the one being registered.
78 * Otherwise a negative error code will be returned.
79 *
80 * Otherwise an attempt will be made to negotiate the requested
81 * API group/major/minor with the hypervisor, and errors returned
82 * if that does not succeed.
83 */
sun4v_hvapi_register(unsigned long group,unsigned long major,unsigned long * minor)84 int sun4v_hvapi_register(unsigned long group, unsigned long major,
85 unsigned long *minor)
86 {
87 struct api_info *p;
88 unsigned long flags;
89 int ret;
90
91 spin_lock_irqsave(&hvapi_lock, flags);
92 p = __get_info(group);
93 ret = -EINVAL;
94 if (p) {
95 if (p->refcnt) {
96 ret = -EINVAL;
97 if (p->major == major) {
98 *minor = p->minor;
99 ret = 0;
100 }
101 } else {
102 unsigned long actual_minor;
103 unsigned long hv_ret;
104
105 hv_ret = sun4v_set_version(group, major, *minor,
106 &actual_minor);
107 ret = -EINVAL;
108 if (hv_ret == HV_EOK) {
109 *minor = actual_minor;
110 p->major = major;
111 p->minor = actual_minor;
112 ret = 0;
113 } else if (hv_ret == HV_EBADTRAP ||
114 hv_ret == HV_ENOTSUPPORTED) {
115 if (p->flags & FLAG_PRE_API) {
116 if (major == 1) {
117 p->major = 1;
118 p->minor = 0;
119 *minor = 0;
120 ret = 0;
121 }
122 }
123 }
124 }
125
126 if (ret == 0)
127 __get_ref(p);
128 }
129 spin_unlock_irqrestore(&hvapi_lock, flags);
130
131 return ret;
132 }
133 EXPORT_SYMBOL(sun4v_hvapi_register);
134
sun4v_hvapi_unregister(unsigned long group)135 void sun4v_hvapi_unregister(unsigned long group)
136 {
137 struct api_info *p;
138 unsigned long flags;
139
140 spin_lock_irqsave(&hvapi_lock, flags);
141 p = __get_info(group);
142 if (p)
143 __put_ref(p);
144 spin_unlock_irqrestore(&hvapi_lock, flags);
145 }
146 EXPORT_SYMBOL(sun4v_hvapi_unregister);
147
sun4v_hvapi_get(unsigned long group,unsigned long * major,unsigned long * minor)148 int sun4v_hvapi_get(unsigned long group,
149 unsigned long *major,
150 unsigned long *minor)
151 {
152 struct api_info *p;
153 unsigned long flags;
154 int ret;
155
156 spin_lock_irqsave(&hvapi_lock, flags);
157 ret = -EINVAL;
158 p = __get_info(group);
159 if (p && p->refcnt) {
160 *major = p->major;
161 *minor = p->minor;
162 ret = 0;
163 }
164 spin_unlock_irqrestore(&hvapi_lock, flags);
165
166 return ret;
167 }
168 EXPORT_SYMBOL(sun4v_hvapi_get);
169
sun4v_hvapi_init(void)170 void __init sun4v_hvapi_init(void)
171 {
172 unsigned long group, major, minor;
173
174 group = HV_GRP_SUN4V;
175 major = 1;
176 minor = 0;
177 if (sun4v_hvapi_register(group, major, &minor))
178 goto bad;
179
180 group = HV_GRP_CORE;
181 major = 1;
182 minor = 1;
183 if (sun4v_hvapi_register(group, major, &minor))
184 goto bad;
185
186 return;
187
188 bad:
189 prom_printf("HVAPI: Cannot register API group "
190 "%lx with major(%u) minor(%u)\n",
191 group, major, minor);
192 prom_halt();
193 }
194