1/*
2 * QEMU vhost-user backend
3 *
4 * Copyright (C) 2018 Red Hat Inc
5 *
6 * Authors:
7 * Marc-André Lureau <marcandre.lureau@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 */
12
13
14#include "qemu/osdep.h"
15#include "qapi/error.h"
16#include "qapi/qmp/qerror.h"
17#include "qemu/error-report.h"
18#include "qom/object_interfaces.h"
19#include "sysemu/vhost-user-backend.h"
20#include "sysemu/kvm.h"
21#include "io/channel-command.h"
22#include "hw/virtio/virtio-bus.h"
23
24static bool
25ioeventfd_enabled(void)
26{
27 return kvm_enabled() && kvm_eventfds_enabled();
28}
29
30int
31vhost_user_backend_dev_init(VhostUserBackend *b, VirtIODevice *vdev,
32 unsigned nvqs, Error **errp)
33{
34 int ret;
35
36 assert(!b->vdev && vdev);
37
38 if (!ioeventfd_enabled()) {
39 error_setg(errp, "vhost initialization failed: requires kvm");
40 return -1;
41 }
42
43 if (!vhost_user_init(&b->vhost_user, &b->chr, errp)) {
44 return -1;
45 }
46
47 b->vdev = vdev;
48 b->dev.nvqs = nvqs;
49 b->dev.vqs = g_new(struct vhost_virtqueue, nvqs);
50
51 ret = vhost_dev_init(&b->dev, &b->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
52 if (ret < 0) {
53 error_setg_errno(errp, -ret, "vhost initialization failed");
54 return -1;
55 }
56
57 return 0;
58}
59
60void
61vhost_user_backend_start(VhostUserBackend *b)
62{
63 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
64 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
65 int ret, i ;
66
67 if (b->started) {
68 return;
69 }
70
71 if (!k->set_guest_notifiers) {
72 error_report("binding does not support guest notifiers");
73 return;
74 }
75
76 ret = vhost_dev_enable_notifiers(&b->dev, b->vdev);
77 if (ret < 0) {
78 return;
79 }
80
81 ret = k->set_guest_notifiers(qbus->parent, b->dev.nvqs, true);
82 if (ret < 0) {
83 error_report("Error binding guest notifier");
84 goto err_host_notifiers;
85 }
86
87 b->dev.acked_features = b->vdev->guest_features;
88 ret = vhost_dev_start(&b->dev, b->vdev);
89 if (ret < 0) {
90 error_report("Error start vhost dev");
91 goto err_guest_notifiers;
92 }
93
94 /* guest_notifier_mask/pending not used yet, so just unmask
95 * everything here. virtio-pci will do the right thing by
96 * enabling/disabling irqfd.
97 */
98 for (i = 0; i < b->dev.nvqs; i++) {
99 vhost_virtqueue_mask(&b->dev, b->vdev,
100 b->dev.vq_index + i, false);
101 }
102
103 b->started = true;
104 return;
105
106err_guest_notifiers:
107 k->set_guest_notifiers(qbus->parent, b->dev.nvqs, false);
108err_host_notifiers:
109 vhost_dev_disable_notifiers(&b->dev, b->vdev);
110}
111
112void
113vhost_user_backend_stop(VhostUserBackend *b)
114{
115 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(b->vdev)));
116 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
117 int ret = 0;
118
119 if (!b->started) {
120 return;
121 }
122
123 vhost_dev_stop(&b->dev, b->vdev);
124
125 if (k->set_guest_notifiers) {
126 ret = k->set_guest_notifiers(qbus->parent,
127 b->dev.nvqs, false);
128 if (ret < 0) {
129 error_report("vhost guest notifier cleanup failed: %d", ret);
130 }
131 }
132 assert(ret >= 0);
133
134 vhost_dev_disable_notifiers(&b->dev, b->vdev);
135 b->started = false;
136}
137
138static void set_chardev(Object *obj, const char *value, Error **errp)
139{
140 VhostUserBackend *b = VHOST_USER_BACKEND(obj);
141 Chardev *chr;
142
143 if (b->completed) {
144 error_setg(errp, QERR_PERMISSION_DENIED);
145 return;
146 }
147
148 g_free(b->chr_name);
149 b->chr_name = g_strdup(value);
150
151 chr = qemu_chr_find(b->chr_name);
152 if (chr == NULL) {
153 error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
154 "Chardev '%s' not found", b->chr_name);
155 return;
156 }
157
158 if (!qemu_chr_fe_init(&b->chr, chr, errp)) {
159 return;
160 }
161
162 b->completed = true;
163 /* could call vhost_dev_init() so early message can be exchanged */
164}
165
166static char *get_chardev(Object *obj, Error **errp)
167{
168 VhostUserBackend *b = VHOST_USER_BACKEND(obj);
169 Chardev *chr = qemu_chr_fe_get_driver(&b->chr);
170
171 if (chr && chr->label) {
172 return g_strdup(chr->label);
173 }
174
175 return NULL;
176}
177
178static void vhost_user_backend_init(Object *obj)
179{
180 object_property_add_str(obj, "chardev", get_chardev, set_chardev, NULL);
181}
182
183static void vhost_user_backend_finalize(Object *obj)
184{
185 VhostUserBackend *b = VHOST_USER_BACKEND(obj);
186
187 g_free(b->dev.vqs);
188 g_free(b->chr_name);
189
190 vhost_user_cleanup(&b->vhost_user);
191 qemu_chr_fe_deinit(&b->chr, true);
192}
193
194static const TypeInfo vhost_user_backend_info = {
195 .name = TYPE_VHOST_USER_BACKEND,
196 .parent = TYPE_OBJECT,
197 .instance_size = sizeof(VhostUserBackend),
198 .instance_init = vhost_user_backend_init,
199 .instance_finalize = vhost_user_backend_finalize,
200 .class_size = sizeof(VhostUserBackendClass),
201};
202
203static void register_types(void)
204{
205 type_register_static(&vhost_user_backend_info);
206}
207
208type_init(register_types);
209