xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision 646c5478) 
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 /* On success, ioeventfd ownership belongs to the caller.  */
151 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
152 {
153     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
154 
155     /* vhost can be used even if ioeventfd=off in the proxy device,
156      * so do not check k->ioeventfd_enabled.
157      */
158     if (!k->ioeventfd_assign) {
159         return -ENOSYS;
160     }
161 
162     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
163         virtio_bus_stop_ioeventfd(bus);
164         /* Remember that we need to restart ioeventfd
165          * when ioeventfd_grabbed becomes zero.
166          */
167         bus->ioeventfd_started = true;
168     }
169     bus->ioeventfd_grabbed++;
170     return 0;
171 }
172 
173 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
174 {
175     assert(bus->ioeventfd_grabbed != 0);
176     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
177         /* Force virtio_bus_start_ioeventfd to act.  */
178         bus->ioeventfd_started = false;
179         virtio_bus_start_ioeventfd(bus);
180     }
181 }
182 
183 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
184 {
185     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
186     DeviceState *proxy = DEVICE(BUS(bus)->parent);
187     VirtIODevice *vdev = virtio_bus_get_device(bus);
188     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
189     int r;
190 
191     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
192         return -ENOSYS;
193     }
194     if (bus->ioeventfd_started) {
195         return 0;
196     }
197 
198     /* Only set our notifier if we have ownership.  */
199     if (!bus->ioeventfd_grabbed) {
200         r = vdc->start_ioeventfd(vdev);
201         if (r < 0) {
202             error_report("%s: failed. Fallback to userspace (slower).", __func__);
203             return r;
204         }
205     }
206     bus->ioeventfd_started = true;
207     return 0;
208 }
209 
210 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
211 {
212     VirtIODevice *vdev;
213     VirtioDeviceClass *vdc;
214 
215     if (!bus->ioeventfd_started) {
216         return;
217     }
218 
219     /* Only remove our notifier if we have ownership.  */
220     if (!bus->ioeventfd_grabbed) {
221         vdev = virtio_bus_get_device(bus);
222         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
223         vdc->stop_ioeventfd(vdev);
224     }
225     bus->ioeventfd_started = false;
226 }
227 
228 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
229 {
230     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
231     DeviceState *proxy = DEVICE(BUS(bus)->parent);
232 
233     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
234 }
235 
236 /*
237  * This function switches ioeventfd on/off in the device.
238  * The caller must set or clear the handlers for the EventNotifier.
239  */
240 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
241 {
242     VirtIODevice *vdev = virtio_bus_get_device(bus);
243     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
244     DeviceState *proxy = DEVICE(BUS(bus)->parent);
245     VirtQueue *vq = virtio_get_queue(vdev, n);
246     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
247     int r = 0;
248 
249     if (!k->ioeventfd_assign) {
250         return -ENOSYS;
251     }
252 
253     if (assign) {
254         r = event_notifier_init(notifier, 1);
255         if (r < 0) {
256             error_report("%s: unable to init event notifier: %s (%d)",
257                          __func__, strerror(-r), r);
258             return r;
259         }
260         r = k->ioeventfd_assign(proxy, notifier, n, true);
261         if (r < 0) {
262             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
263             goto cleanup_event_notifier;
264         }
265         return 0;
266     } else {
267         k->ioeventfd_assign(proxy, notifier, n, false);
268     }
269 
270 cleanup_event_notifier:
271     /* Test and clear notifier after disabling event,
272      * in case poll callback didn't have time to run.
273      */
274     virtio_queue_host_notifier_read(notifier);
275     event_notifier_cleanup(notifier);
276     return r;
277 }
278 
279 static char *virtio_bus_get_dev_path(DeviceState *dev)
280 {
281     BusState *bus = qdev_get_parent_bus(dev);
282     DeviceState *proxy = DEVICE(bus->parent);
283     return qdev_get_dev_path(proxy);
284 }
285 
286 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
287 {
288     return NULL;
289 }
290 
291 static void virtio_bus_class_init(ObjectClass *klass, void *data)
292 {
293     BusClass *bus_class = BUS_CLASS(klass);
294     bus_class->get_dev_path = virtio_bus_get_dev_path;
295     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
296 }
297 
298 static const TypeInfo virtio_bus_info = {
299     .name = TYPE_VIRTIO_BUS,
300     .parent = TYPE_BUS,
301     .instance_size = sizeof(VirtioBusState),
302     .abstract = true,
303     .class_size = sizeof(VirtioBusClass),
304     .class_init = virtio_bus_class_init
305 };
306 
307 static void virtio_register_types(void)
308 {
309     type_register_static(&virtio_bus_info);
310 }
311 
312 type_init(virtio_register_types)
313