xref: /qemu/hw/virtio/virtio-bus.c (revision 8e93cef14e6f32adf6914b30b096039e6264f0e3) 
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 /*
151  * This function handles both assigning the ioeventfd handler and
152  * registering it with the kernel.
153  * assign: register/deregister ioeventfd with the kernel
154  * set_handler: use the generic ioeventfd handler
155  */
156 int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus,
157                                int n, bool assign, bool set_handler)
158 {
159     VirtIODevice *vdev = virtio_bus_get_device(bus);
160     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
161     VirtQueue *vq = virtio_get_queue(vdev, n);
162     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
163     int r = 0;
164 
165     if (assign) {
166         r = event_notifier_init(notifier, 1);
167         if (r < 0) {
168             error_report("%s: unable to init event notifier: %s (%d)",
169                          __func__, strerror(-r), r);
170             return r;
171         }
172         virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
173         r = k->ioeventfd_assign(proxy, notifier, n, assign);
174         if (r < 0) {
175             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
176             virtio_queue_set_host_notifier_fd_handler(vq, false, false);
177             event_notifier_cleanup(notifier);
178             return r;
179         }
180     } else {
181         k->ioeventfd_assign(proxy, notifier, n, assign);
182         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
183         event_notifier_cleanup(notifier);
184     }
185     return r;
186 }
187 
188 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
189 {
190     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
191     DeviceState *proxy = DEVICE(BUS(bus)->parent);
192     VirtIODevice *vdev = virtio_bus_get_device(bus);
193     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
194     int r;
195 
196     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
197         return -ENOSYS;
198     }
199     if (bus->ioeventfd_started || bus->ioeventfd_disabled) {
200         return 0;
201     }
202     r = vdc->start_ioeventfd(vdev);
203     if (r < 0) {
204         error_report("%s: failed. Fallback to userspace (slower).", __func__);
205         return r;
206     }
207     bus->ioeventfd_started = true;
208     return 0;
209 }
210 
211 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
212 {
213     VirtIODevice *vdev;
214     VirtioDeviceClass *vdc;
215 
216     if (!bus->ioeventfd_started) {
217         return;
218     }
219 
220     vdev = virtio_bus_get_device(bus);
221     vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
222     vdc->stop_ioeventfd(vdev);
223     bus->ioeventfd_started = false;
224 }
225 
226 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
227 {
228     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
229     DeviceState *proxy = DEVICE(BUS(bus)->parent);
230 
231     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
232 }
233 
234 /*
235  * This function switches from/to the generic ioeventfd handler.
236  * assign==false means 'use generic ioeventfd handler'.
237  */
238 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
239 {
240     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
241     DeviceState *proxy = DEVICE(BUS(bus)->parent);
242 
243     if (!k->ioeventfd_assign) {
244         return -ENOSYS;
245     }
246     bus->ioeventfd_disabled = assign;
247     if (assign) {
248         /*
249          * Stop using the generic ioeventfd, we are doing eventfd handling
250          * ourselves below
251          *
252          * FIXME: We should just switch the handler and not deassign the
253          * ioeventfd.
254          * Otherwise, there's a window where we don't have an
255          * ioeventfd and we may end up with a notification where
256          * we don't expect one.
257          */
258         virtio_bus_stop_ioeventfd(bus);
259     }
260     return set_host_notifier_internal(proxy, bus, n, assign, false);
261 }
262 
263 static char *virtio_bus_get_dev_path(DeviceState *dev)
264 {
265     BusState *bus = qdev_get_parent_bus(dev);
266     DeviceState *proxy = DEVICE(bus->parent);
267     return qdev_get_dev_path(proxy);
268 }
269 
270 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
271 {
272     return NULL;
273 }
274 
275 static void virtio_bus_class_init(ObjectClass *klass, void *data)
276 {
277     BusClass *bus_class = BUS_CLASS(klass);
278     bus_class->get_dev_path = virtio_bus_get_dev_path;
279     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
280 }
281 
282 static const TypeInfo virtio_bus_info = {
283     .name = TYPE_VIRTIO_BUS,
284     .parent = TYPE_BUS,
285     .instance_size = sizeof(VirtioBusState),
286     .abstract = true,
287     .class_size = sizeof(VirtioBusClass),
288     .class_init = virtio_bus_class_init
289 };
290 
291 static void virtio_register_types(void)
292 {
293     type_register_static(&virtio_bus_info);
294 }
295 
296 type_init(virtio_register_types)
297