xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision dfbd2768) 
1 /*
2  * VirtioBus
3  *
4  *  Copyright (C) 2012 : GreenSocs Ltd
5  *      http://www.greensocs.com/ , email: info@greensocs.com
6  *
7  *  Developed by :
8  *  Frederic Konrad   <fred.konrad@greensocs.com>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation, either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License along
21  * with this program; if not, see <http://www.gnu.org/licenses/>.
22  *
23  */
24 
25 #include "qemu/osdep.h"
26 #include "hw/hw.h"
27 #include "qemu/error-report.h"
28 #include "hw/qdev.h"
29 #include "hw/virtio/virtio-bus.h"
30 #include "hw/virtio/virtio.h"
31 
32 /* #define DEBUG_VIRTIO_BUS */
33 
34 #ifdef DEBUG_VIRTIO_BUS
35 #define DPRINTF(fmt, ...) \
36 do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
37 #else
38 #define DPRINTF(fmt, ...) do { } while (0)
39 #endif
40 
41 /* A VirtIODevice is being plugged */
42 void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
43 {
44     DeviceState *qdev = DEVICE(vdev);
45     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
46     VirtioBusState *bus = VIRTIO_BUS(qbus);
47     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
48     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
49 
50     DPRINTF("%s: plug device.\n", qbus->name);
51 
52     if (klass->pre_plugged != NULL) {
53         klass->pre_plugged(qbus->parent, errp);
54     }
55 
56     /* Get the features of the plugged device. */
57     assert(vdc->get_features != NULL);
58     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
59                                             errp);
60 
61     if (klass->device_plugged != NULL) {
62         klass->device_plugged(qbus->parent, errp);
63     }
64 }
65 
66 /* Reset the virtio_bus */
67 void virtio_bus_reset(VirtioBusState *bus)
68 {
69     VirtIODevice *vdev = virtio_bus_get_device(bus);
70 
71     DPRINTF("%s: reset device.\n", BUS(bus)->name);
72     if (vdev != NULL) {
73         virtio_reset(vdev);
74     }
75 }
76 
77 /* A VirtIODevice is being unplugged */
78 void virtio_bus_device_unplugged(VirtIODevice *vdev)
79 {
80     DeviceState *qdev = DEVICE(vdev);
81     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
82     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
83 
84     DPRINTF("%s: remove device.\n", qbus->name);
85 
86     if (vdev != NULL) {
87         if (klass->device_unplugged != NULL) {
88             klass->device_unplugged(qbus->parent);
89         }
90     }
91 }
92 
93 /* Get the device id of the plugged device. */
94 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
95 {
96     VirtIODevice *vdev = virtio_bus_get_device(bus);
97     assert(vdev != NULL);
98     return vdev->device_id;
99 }
100 
101 /* Get the config_len field of the plugged device. */
102 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
103 {
104     VirtIODevice *vdev = virtio_bus_get_device(bus);
105     assert(vdev != NULL);
106     return vdev->config_len;
107 }
108 
109 /* Get bad features of the plugged device. */
110 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
111 {
112     VirtIODevice *vdev = virtio_bus_get_device(bus);
113     VirtioDeviceClass *k;
114 
115     assert(vdev != NULL);
116     k = VIRTIO_DEVICE_GET_CLASS(vdev);
117     if (k->bad_features != NULL) {
118         return k->bad_features(vdev);
119     } else {
120         return 0;
121     }
122 }
123 
124 /* Get config of the plugged device. */
125 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
126 {
127     VirtIODevice *vdev = virtio_bus_get_device(bus);
128     VirtioDeviceClass *k;
129 
130     assert(vdev != NULL);
131     k = VIRTIO_DEVICE_GET_CLASS(vdev);
132     if (k->get_config != NULL) {
133         k->get_config(vdev, config);
134     }
135 }
136 
137 /* Set config of the plugged device. */
138 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
139 {
140     VirtIODevice *vdev = virtio_bus_get_device(bus);
141     VirtioDeviceClass *k;
142 
143     assert(vdev != NULL);
144     k = VIRTIO_DEVICE_GET_CLASS(vdev);
145     if (k->set_config != NULL) {
146         k->set_config(vdev, config);
147     }
148 }
149 
150 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
151 {
152     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
153     DeviceState *proxy = DEVICE(BUS(bus)->parent);
154     VirtIODevice *vdev = virtio_bus_get_device(bus);
155     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
156     int r;
157 
158     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
159         return -ENOSYS;
160     }
161     if (bus->ioeventfd_started) {
162         return 0;
163     }
164     r = vdc->start_ioeventfd(vdev);
165     if (r < 0) {
166         error_report("%s: failed. Fallback to userspace (slower).", __func__);
167         return r;
168     }
169     bus->ioeventfd_started = true;
170     return 0;
171 }
172 
173 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
174 {
175     VirtIODevice *vdev;
176     VirtioDeviceClass *vdc;
177 
178     if (!bus->ioeventfd_started) {
179         return;
180     }
181 
182     vdev = virtio_bus_get_device(bus);
183     vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
184     vdc->stop_ioeventfd(vdev);
185     bus->ioeventfd_started = false;
186 }
187 
188 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
189 {
190     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
191     DeviceState *proxy = DEVICE(BUS(bus)->parent);
192 
193     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
194 }
195 
196 /*
197  * This function switches ioeventfd on/off in the device.
198  * The caller must set or clear the handlers for the EventNotifier.
199  */
200 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
201 {
202     VirtIODevice *vdev = virtio_bus_get_device(bus);
203     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
204     DeviceState *proxy = DEVICE(BUS(bus)->parent);
205     VirtQueue *vq = virtio_get_queue(vdev, n);
206     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
207     int r = 0;
208 
209     if (!k->ioeventfd_assign) {
210         return -ENOSYS;
211     }
212 
213     if (assign) {
214         assert(!bus->ioeventfd_started);
215         r = event_notifier_init(notifier, 1);
216         if (r < 0) {
217             error_report("%s: unable to init event notifier: %s (%d)",
218                          __func__, strerror(-r), r);
219             return r;
220         }
221         r = k->ioeventfd_assign(proxy, notifier, n, true);
222         if (r < 0) {
223             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
224             goto cleanup_event_notifier;
225         }
226         return 0;
227     } else {
228         if (!bus->ioeventfd_started) {
229             return 0;
230         }
231         k->ioeventfd_assign(proxy, notifier, n, false);
232     }
233 
234 cleanup_event_notifier:
235     /* Test and clear notifier after disabling event,
236      * in case poll callback didn't have time to run.
237      */
238     virtio_queue_host_notifier_read(notifier);
239     event_notifier_cleanup(notifier);
240     return r;
241 }
242 
243 static char *virtio_bus_get_dev_path(DeviceState *dev)
244 {
245     BusState *bus = qdev_get_parent_bus(dev);
246     DeviceState *proxy = DEVICE(bus->parent);
247     return qdev_get_dev_path(proxy);
248 }
249 
250 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
251 {
252     return NULL;
253 }
254 
255 static void virtio_bus_class_init(ObjectClass *klass, void *data)
256 {
257     BusClass *bus_class = BUS_CLASS(klass);
258     bus_class->get_dev_path = virtio_bus_get_dev_path;
259     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
260 }
261 
262 static const TypeInfo virtio_bus_info = {
263     .name = TYPE_VIRTIO_BUS,
264     .parent = TYPE_BUS,
265     .instance_size = sizeof(VirtioBusState),
266     .abstract = true,
267     .class_size = sizeof(VirtioBusClass),
268     .class_init = virtio_bus_class_init
269 };
270 
271 static void virtio_register_types(void)
272 {
273     type_register_static(&virtio_bus_info);
274 }
275 
276 type_init(virtio_register_types)
277