xref: /qemu/hw/virtio/virtio-bus.c (revision 20daa90a) 
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 #include "exec/address-spaces.h"
32 
33 /* #define DEBUG_VIRTIO_BUS */
34 
35 #ifdef DEBUG_VIRTIO_BUS
36 #define DPRINTF(fmt, ...) \
37 do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
38 #else
39 #define DPRINTF(fmt, ...) do { } while (0)
40 #endif
41 
42 /* A VirtIODevice is being plugged */
43 void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
44 {
45     DeviceState *qdev = DEVICE(vdev);
46     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
47     VirtioBusState *bus = VIRTIO_BUS(qbus);
48     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
49     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
50     bool has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
51 
52     DPRINTF("%s: plug device.\n", qbus->name);
53 
54     if (klass->pre_plugged != NULL) {
55         klass->pre_plugged(qbus->parent, errp);
56     }
57 
58     /* Get the features of the plugged device. */
59     assert(vdc->get_features != NULL);
60     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
61                                             errp);
62 
63     if (klass->device_plugged != NULL) {
64         klass->device_plugged(qbus->parent, errp);
65     }
66 
67     if (klass->get_dma_as != NULL && has_iommu) {
68         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
69         vdev->dma_as = klass->get_dma_as(qbus->parent);
70     } else {
71         vdev->dma_as = &address_space_memory;
72     }
73 }
74 
75 /* Reset the virtio_bus */
76 void virtio_bus_reset(VirtioBusState *bus)
77 {
78     VirtIODevice *vdev = virtio_bus_get_device(bus);
79 
80     DPRINTF("%s: reset device.\n", BUS(bus)->name);
81     if (vdev != NULL) {
82         virtio_reset(vdev);
83     }
84 }
85 
86 /* A VirtIODevice is being unplugged */
87 void virtio_bus_device_unplugged(VirtIODevice *vdev)
88 {
89     DeviceState *qdev = DEVICE(vdev);
90     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
91     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
92 
93     DPRINTF("%s: remove device.\n", qbus->name);
94 
95     if (vdev != NULL) {
96         if (klass->device_unplugged != NULL) {
97             klass->device_unplugged(qbus->parent);
98         }
99     }
100 }
101 
102 /* Get the device id of the plugged device. */
103 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
104 {
105     VirtIODevice *vdev = virtio_bus_get_device(bus);
106     assert(vdev != NULL);
107     return vdev->device_id;
108 }
109 
110 /* Get the config_len field of the plugged device. */
111 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
112 {
113     VirtIODevice *vdev = virtio_bus_get_device(bus);
114     assert(vdev != NULL);
115     return vdev->config_len;
116 }
117 
118 /* Get bad features of the plugged device. */
119 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
120 {
121     VirtIODevice *vdev = virtio_bus_get_device(bus);
122     VirtioDeviceClass *k;
123 
124     assert(vdev != NULL);
125     k = VIRTIO_DEVICE_GET_CLASS(vdev);
126     if (k->bad_features != NULL) {
127         return k->bad_features(vdev);
128     } else {
129         return 0;
130     }
131 }
132 
133 /* Get config of the plugged device. */
134 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
135 {
136     VirtIODevice *vdev = virtio_bus_get_device(bus);
137     VirtioDeviceClass *k;
138 
139     assert(vdev != NULL);
140     k = VIRTIO_DEVICE_GET_CLASS(vdev);
141     if (k->get_config != NULL) {
142         k->get_config(vdev, config);
143     }
144 }
145 
146 /* Set config of the plugged device. */
147 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
148 {
149     VirtIODevice *vdev = virtio_bus_get_device(bus);
150     VirtioDeviceClass *k;
151 
152     assert(vdev != NULL);
153     k = VIRTIO_DEVICE_GET_CLASS(vdev);
154     if (k->set_config != NULL) {
155         k->set_config(vdev, config);
156     }
157 }
158 
159 /* On success, ioeventfd ownership belongs to the caller.  */
160 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
161 {
162     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
163 
164     /* vhost can be used even if ioeventfd=off in the proxy device,
165      * so do not check k->ioeventfd_enabled.
166      */
167     if (!k->ioeventfd_assign) {
168         return -ENOSYS;
169     }
170 
171     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
172         virtio_bus_stop_ioeventfd(bus);
173         /* Remember that we need to restart ioeventfd
174          * when ioeventfd_grabbed becomes zero.
175          */
176         bus->ioeventfd_started = true;
177     }
178     bus->ioeventfd_grabbed++;
179     return 0;
180 }
181 
182 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
183 {
184     assert(bus->ioeventfd_grabbed != 0);
185     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
186         /* Force virtio_bus_start_ioeventfd to act.  */
187         bus->ioeventfd_started = false;
188         virtio_bus_start_ioeventfd(bus);
189     }
190 }
191 
192 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
193 {
194     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
195     DeviceState *proxy = DEVICE(BUS(bus)->parent);
196     VirtIODevice *vdev = virtio_bus_get_device(bus);
197     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
198     int r;
199 
200     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
201         return -ENOSYS;
202     }
203     if (bus->ioeventfd_started) {
204         return 0;
205     }
206 
207     /* Only set our notifier if we have ownership.  */
208     if (!bus->ioeventfd_grabbed) {
209         r = vdc->start_ioeventfd(vdev);
210         if (r < 0) {
211             error_report("%s: failed. Fallback to userspace (slower).", __func__);
212             return r;
213         }
214     }
215     bus->ioeventfd_started = true;
216     return 0;
217 }
218 
219 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
220 {
221     VirtIODevice *vdev;
222     VirtioDeviceClass *vdc;
223 
224     if (!bus->ioeventfd_started) {
225         return;
226     }
227 
228     /* Only remove our notifier if we have ownership.  */
229     if (!bus->ioeventfd_grabbed) {
230         vdev = virtio_bus_get_device(bus);
231         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
232         vdc->stop_ioeventfd(vdev);
233     }
234     bus->ioeventfd_started = false;
235 }
236 
237 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
238 {
239     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
240     DeviceState *proxy = DEVICE(BUS(bus)->parent);
241 
242     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
243 }
244 
245 /*
246  * This function switches ioeventfd on/off in the device.
247  * The caller must set or clear the handlers for the EventNotifier.
248  */
249 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
250 {
251     VirtIODevice *vdev = virtio_bus_get_device(bus);
252     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
253     DeviceState *proxy = DEVICE(BUS(bus)->parent);
254     VirtQueue *vq = virtio_get_queue(vdev, n);
255     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
256     int r = 0;
257 
258     if (!k->ioeventfd_assign) {
259         return -ENOSYS;
260     }
261 
262     if (assign) {
263         r = event_notifier_init(notifier, 1);
264         if (r < 0) {
265             error_report("%s: unable to init event notifier: %s (%d)",
266                          __func__, strerror(-r), r);
267             return r;
268         }
269         r = k->ioeventfd_assign(proxy, notifier, n, true);
270         if (r < 0) {
271             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
272             goto cleanup_event_notifier;
273         }
274         return 0;
275     } else {
276         k->ioeventfd_assign(proxy, notifier, n, false);
277     }
278 
279 cleanup_event_notifier:
280     /* Test and clear notifier after disabling event,
281      * in case poll callback didn't have time to run.
282      */
283     virtio_queue_host_notifier_read(notifier);
284     event_notifier_cleanup(notifier);
285     return r;
286 }
287 
288 static char *virtio_bus_get_dev_path(DeviceState *dev)
289 {
290     BusState *bus = qdev_get_parent_bus(dev);
291     DeviceState *proxy = DEVICE(bus->parent);
292     return qdev_get_dev_path(proxy);
293 }
294 
295 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
296 {
297     return NULL;
298 }
299 
300 static void virtio_bus_class_init(ObjectClass *klass, void *data)
301 {
302     BusClass *bus_class = BUS_CLASS(klass);
303     bus_class->get_dev_path = virtio_bus_get_dev_path;
304     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
305 }
306 
307 static const TypeInfo virtio_bus_info = {
308     .name = TYPE_VIRTIO_BUS,
309     .parent = TYPE_BUS,
310     .instance_size = sizeof(VirtioBusState),
311     .abstract = true,
312     .class_size = sizeof(VirtioBusClass),
313     .class_init = virtio_bus_class_init
314 };
315 
316 static void virtio_register_types(void)
317 {
318     type_register_static(&virtio_bus_info);
319 }
320 
321 type_init(virtio_register_types)
322