aboutsummaryrefslogtreecommitdiff
path: root/hw/xen/xen-backend.c
blob: 5b0fb76eaeb38106f35ceac2830b1375f434b81e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
/*
 * Copyright (c) 2018  Citrix Systems Inc.
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 */

#include "qemu/osdep.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "hw/xen/xen-backend.h"
#include "hw/xen/xen-bus.h"

typedef struct XenBackendImpl {
    const char *type;
    XenBackendDeviceCreate create;
    XenBackendDeviceDestroy destroy;
} XenBackendImpl;

struct XenBackendInstance {
    QLIST_ENTRY(XenBackendInstance) entry;
    const XenBackendImpl *impl;
    XenBus *xenbus;
    char *name;
    XenDevice *xendev;
};

static GHashTable *xen_backend_table_get(void)
{
    static GHashTable *table;

    if (table == NULL) {
        table = g_hash_table_new(g_str_hash, g_str_equal);
    }

    return table;
}

static void xen_backend_table_add(XenBackendImpl *impl)
{
    g_hash_table_insert(xen_backend_table_get(), (void *)impl->type, impl);
}

static const char **xen_backend_table_keys(unsigned int *count)
{
    return (const char **)g_hash_table_get_keys_as_array(
        xen_backend_table_get(), count);
}

static const XenBackendImpl *xen_backend_table_lookup(const char *type)
{
    return g_hash_table_lookup(xen_backend_table_get(), type);
}

void xen_backend_register(const XenBackendInfo *info)
{
    XenBackendImpl *impl = g_new0(XenBackendImpl, 1);

    g_assert(info->type);

    if (xen_backend_table_lookup(info->type)) {
        error_report("attempt to register duplicate Xen backend type '%s'",
                     info->type);
        abort();
    }

    if (!info->create) {
        error_report("backend type '%s' has no creator", info->type);
        abort();
    }

    impl->type = info->type;
    impl->create = info->create;
    impl->destroy = info->destroy;

    xen_backend_table_add(impl);
}

const char **xen_backend_get_types(unsigned int *count)
{
    return xen_backend_table_keys(count);
}

static QLIST_HEAD(, XenBackendInstance) backend_list;

static void xen_backend_list_add(XenBackendInstance *backend)
{
    QLIST_INSERT_HEAD(&backend_list, backend, entry);
}

static XenBackendInstance *xen_backend_list_find(XenDevice *xendev)
{
    XenBackendInstance *backend;

    QLIST_FOREACH(backend, &backend_list, entry) {
        if (backend->xendev == xendev) {
            return backend;
        }
    }

    return NULL;
}

static void xen_backend_list_remove(XenBackendInstance *backend)
{
    QLIST_REMOVE(backend, entry);
}

void xen_backend_device_create(XenBus *xenbus, const char *type,
                               const char *name, QDict *opts, Error **errp)
{
    ERRP_GUARD();
    const XenBackendImpl *impl = xen_backend_table_lookup(type);
    XenBackendInstance *backend;

    if (!impl) {
        return;
    }

    backend = g_new0(XenBackendInstance, 1);
    backend->xenbus = xenbus;
    backend->name = g_strdup(name);

    impl->create(backend, opts, errp);
    if (*errp) {
        g_free(backend->name);
        g_free(backend);
        return;
    }

    backend->impl = impl;
    xen_backend_list_add(backend);
}

XenBus *xen_backend_get_bus(XenBackendInstance *backend)
{
    return backend->xenbus;
}

const char *xen_backend_get_name(XenBackendInstance *backend)
{
    return backend->name;
}

void xen_backend_set_device(XenBackendInstance *backend,
                            XenDevice *xendev)
{
    g_assert(!backend->xendev);
    backend->xendev = xendev;
}

XenDevice *xen_backend_get_device(XenBackendInstance *backend)
{
    return backend->xendev;
}


bool xen_backend_try_device_destroy(XenDevice *xendev, Error **errp)
{
    XenBackendInstance *backend = xen_backend_list_find(xendev);
    const XenBackendImpl *impl;

    if (!backend) {
        return false;
    }

    impl = backend->impl;
    impl->destroy(backend, errp);

    xen_backend_list_remove(backend);
    g_free(backend->name);
    g_free(backend);

    return true;
}