xref: /qemu/hw/virtio/virtio-bus.c (revision fa283a4a8be621d9be88c87458355aa4800b731c) 
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 static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus,
151                                       int n, bool assign)
152 {
153     VirtIODevice *vdev = virtio_bus_get_device(bus);
154     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
155     VirtQueue *vq = virtio_get_queue(vdev, n);
156     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
157     int r = 0;
158 
159     if (assign) {
160         r = event_notifier_init(notifier, 1);
161         if (r < 0) {
162             error_report("%s: unable to init event notifier: %s (%d)",
163                          __func__, strerror(-r), r);
164             return r;
165         }
166         r = k->ioeventfd_assign(proxy, notifier, n, true);
167         if (r < 0) {
168             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
169             goto cleanup_event_notifier;
170         }
171         return 0;
172     } else {
173         k->ioeventfd_assign(proxy, notifier, n, false);
174     }
175 
176 cleanup_event_notifier:
177     /* Test and clear notifier after disabling event,
178      * in case poll callback didn't have time to run.
179      */
180     virtio_queue_host_notifier_read(notifier);
181     event_notifier_cleanup(notifier);
182     return r;
183 }
184 
185 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
186 {
187     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
188     DeviceState *proxy = DEVICE(BUS(bus)->parent);
189     VirtIODevice *vdev = virtio_bus_get_device(bus);
190     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
191     int r;
192 
193     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
194         return -ENOSYS;
195     }
196     if (bus->ioeventfd_started) {
197         return 0;
198     }
199     r = vdc->start_ioeventfd(vdev);
200     if (r < 0) {
201         error_report("%s: failed. Fallback to userspace (slower).", __func__);
202         return r;
203     }
204     bus->ioeventfd_started = true;
205     return 0;
206 }
207 
208 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
209 {
210     VirtIODevice *vdev;
211     VirtioDeviceClass *vdc;
212 
213     if (!bus->ioeventfd_started) {
214         return;
215     }
216 
217     vdev = virtio_bus_get_device(bus);
218     vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
219     vdc->stop_ioeventfd(vdev);
220     bus->ioeventfd_started = false;
221 }
222 
223 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
224 {
225     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
226     DeviceState *proxy = DEVICE(BUS(bus)->parent);
227 
228     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
229 }
230 
231 /*
232  * This function switches ioeventfd on/off in the device.
233  * The caller must set or clear the handlers for the EventNotifier.
234  */
235 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
236 {
237     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
238     DeviceState *proxy = DEVICE(BUS(bus)->parent);
239 
240     if (!k->ioeventfd_assign) {
241         return -ENOSYS;
242     }
243     if (assign) {
244         assert(!bus->ioeventfd_started);
245     } else {
246         if (!bus->ioeventfd_started) {
247             return 0;
248         }
249     }
250     return set_host_notifier_internal(proxy, bus, n, assign);
251 }
252 
253 static char *virtio_bus_get_dev_path(DeviceState *dev)
254 {
255     BusState *bus = qdev_get_parent_bus(dev);
256     DeviceState *proxy = DEVICE(bus->parent);
257     return qdev_get_dev_path(proxy);
258 }
259 
260 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
261 {
262     return NULL;
263 }
264 
265 static void virtio_bus_class_init(ObjectClass *klass, void *data)
266 {
267     BusClass *bus_class = BUS_CLASS(klass);
268     bus_class->get_dev_path = virtio_bus_get_dev_path;
269     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
270 }
271 
272 static const TypeInfo virtio_bus_info = {
273     .name = TYPE_VIRTIO_BUS,
274     .parent = TYPE_BUS,
275     .instance_size = sizeof(VirtioBusState),
276     .abstract = true,
277     .class_size = sizeof(VirtioBusClass),
278     .class_init = virtio_bus_class_init
279 };
280 
281 static void virtio_register_types(void)
282 {
283     type_register_static(&virtio_bus_info);
284 }
285 
286 type_init(virtio_register_types)
287