xref: /qemu/hw/virtio/virtio-bus.c (revision 1158bb2a) 
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->device_plugged != NULL) {
53         klass->device_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     if (klass->post_plugged != NULL) {
61         klass->post_plugged(qbus->parent, errp);
62     }
63 }
64 
65 /* Reset the virtio_bus */
66 void virtio_bus_reset(VirtioBusState *bus)
67 {
68     VirtIODevice *vdev = virtio_bus_get_device(bus);
69 
70     DPRINTF("%s: reset device.\n", BUS(bus)->name);
71     if (vdev != NULL) {
72         virtio_reset(vdev);
73     }
74 }
75 
76 /* A VirtIODevice is being unplugged */
77 void virtio_bus_device_unplugged(VirtIODevice *vdev)
78 {
79     DeviceState *qdev = DEVICE(vdev);
80     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
81     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
82 
83     DPRINTF("%s: remove device.\n", qbus->name);
84 
85     if (vdev != NULL) {
86         if (klass->device_unplugged != NULL) {
87             klass->device_unplugged(qbus->parent);
88         }
89     }
90 }
91 
92 /* Get the device id of the plugged device. */
93 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
94 {
95     VirtIODevice *vdev = virtio_bus_get_device(bus);
96     assert(vdev != NULL);
97     return vdev->device_id;
98 }
99 
100 /* Get the config_len field of the plugged device. */
101 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
102 {
103     VirtIODevice *vdev = virtio_bus_get_device(bus);
104     assert(vdev != NULL);
105     return vdev->config_len;
106 }
107 
108 /* Get bad features of the plugged device. */
109 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
110 {
111     VirtIODevice *vdev = virtio_bus_get_device(bus);
112     VirtioDeviceClass *k;
113 
114     assert(vdev != NULL);
115     k = VIRTIO_DEVICE_GET_CLASS(vdev);
116     if (k->bad_features != NULL) {
117         return k->bad_features(vdev);
118     } else {
119         return 0;
120     }
121 }
122 
123 /* Get config of the plugged device. */
124 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
125 {
126     VirtIODevice *vdev = virtio_bus_get_device(bus);
127     VirtioDeviceClass *k;
128 
129     assert(vdev != NULL);
130     k = VIRTIO_DEVICE_GET_CLASS(vdev);
131     if (k->get_config != NULL) {
132         k->get_config(vdev, config);
133     }
134 }
135 
136 /* Set config of the plugged device. */
137 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
138 {
139     VirtIODevice *vdev = virtio_bus_get_device(bus);
140     VirtioDeviceClass *k;
141 
142     assert(vdev != NULL);
143     k = VIRTIO_DEVICE_GET_CLASS(vdev);
144     if (k->set_config != NULL) {
145         k->set_config(vdev, config);
146     }
147 }
148 
149 /*
150  * This function handles both assigning the ioeventfd handler and
151  * registering it with the kernel.
152  * assign: register/deregister ioeventfd with the kernel
153  * set_handler: use the generic ioeventfd handler
154  */
155 static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus,
156                                       int n, bool assign, bool set_handler)
157 {
158     VirtIODevice *vdev = virtio_bus_get_device(bus);
159     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
160     VirtQueue *vq = virtio_get_queue(vdev, n);
161     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
162     int r = 0;
163 
164     if (assign) {
165         r = event_notifier_init(notifier, 1);
166         if (r < 0) {
167             error_report("%s: unable to init event notifier: %d", __func__, r);
168             return r;
169         }
170         virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
171         r = k->ioeventfd_assign(proxy, notifier, n, assign);
172         if (r < 0) {
173             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
174             virtio_queue_set_host_notifier_fd_handler(vq, false, false);
175             event_notifier_cleanup(notifier);
176             return r;
177         }
178     } else {
179         k->ioeventfd_assign(proxy, notifier, n, assign);
180         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
181         event_notifier_cleanup(notifier);
182     }
183     return r;
184 }
185 
186 void virtio_bus_start_ioeventfd(VirtioBusState *bus)
187 {
188     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
189     DeviceState *proxy = DEVICE(BUS(bus)->parent);
190     VirtIODevice *vdev;
191     int n, r;
192 
193     if (!k->ioeventfd_started || k->ioeventfd_started(proxy)) {
194         return;
195     }
196     if (k->ioeventfd_disabled(proxy)) {
197         return;
198     }
199     vdev = virtio_bus_get_device(bus);
200     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
201         if (!virtio_queue_get_num(vdev, n)) {
202             continue;
203         }
204         r = set_host_notifier_internal(proxy, bus, n, true, true);
205         if (r < 0) {
206             goto assign_error;
207         }
208     }
209     k->ioeventfd_set_started(proxy, true, false);
210     return;
211 
212 assign_error:
213     while (--n >= 0) {
214         if (!virtio_queue_get_num(vdev, n)) {
215             continue;
216         }
217 
218         r = set_host_notifier_internal(proxy, bus, n, false, false);
219         assert(r >= 0);
220     }
221     k->ioeventfd_set_started(proxy, false, true);
222     error_report("%s: failed. Fallback to userspace (slower).", __func__);
223 }
224 
225 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
226 {
227     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
228     DeviceState *proxy = DEVICE(BUS(bus)->parent);
229     VirtIODevice *vdev;
230     int n, r;
231 
232     if (!k->ioeventfd_started || !k->ioeventfd_started(proxy)) {
233         return;
234     }
235     vdev = virtio_bus_get_device(bus);
236     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
237         if (!virtio_queue_get_num(vdev, n)) {
238             continue;
239         }
240         r = set_host_notifier_internal(proxy, bus, n, false, false);
241         assert(r >= 0);
242     }
243     k->ioeventfd_set_started(proxy, false, false);
244 }
245 
246 /*
247  * This function switches from/to the generic ioeventfd handler.
248  * assign==false means 'use generic ioeventfd handler'.
249  */
250 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
251 {
252     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
253     DeviceState *proxy = DEVICE(BUS(bus)->parent);
254 
255     if (!k->ioeventfd_started) {
256         return -ENOSYS;
257     }
258     k->ioeventfd_set_disabled(proxy, assign);
259     if (assign) {
260         /*
261          * Stop using the generic ioeventfd, we are doing eventfd handling
262          * ourselves below
263          *
264          * FIXME: We should just switch the handler and not deassign the
265          * ioeventfd.
266          * Otherwise, there's a window where we don't have an
267          * ioeventfd and we may end up with a notification where
268          * we don't expect one.
269          */
270         virtio_bus_stop_ioeventfd(bus);
271     }
272     return set_host_notifier_internal(proxy, bus, n, assign, false);
273 }
274 
275 static char *virtio_bus_get_dev_path(DeviceState *dev)
276 {
277     BusState *bus = qdev_get_parent_bus(dev);
278     DeviceState *proxy = DEVICE(bus->parent);
279     return qdev_get_dev_path(proxy);
280 }
281 
282 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
283 {
284     return NULL;
285 }
286 
287 static void virtio_bus_class_init(ObjectClass *klass, void *data)
288 {
289     BusClass *bus_class = BUS_CLASS(klass);
290     bus_class->get_dev_path = virtio_bus_get_dev_path;
291     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
292 }
293 
294 static const TypeInfo virtio_bus_info = {
295     .name = TYPE_VIRTIO_BUS,
296     .parent = TYPE_BUS,
297     .instance_size = sizeof(VirtioBusState),
298     .abstract = true,
299     .class_size = sizeof(VirtioBusClass),
300     .class_init = virtio_bus_class_init
301 };
302 
303 static void virtio_register_types(void)
304 {
305     type_register_static(&virtio_bus_info);
306 }
307 
308 type_init(virtio_register_types)
309