xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision 135b03cb) 
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 "qemu/error-report.h"
27 #include "qemu/module.h"
28 #include "qapi/error.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     Error *local_err = NULL;
52 
53     DPRINTF("%s: plug device.\n", qbus->name);
54 
55     if (klass->pre_plugged != NULL) {
56         klass->pre_plugged(qbus->parent, &local_err);
57         if (local_err) {
58             error_propagate(errp, local_err);
59             return;
60         }
61     }
62 
63     /* Get the features of the plugged device. */
64     assert(vdc->get_features != NULL);
65     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
66                                             &local_err);
67     if (local_err) {
68         error_propagate(errp, local_err);
69         return;
70     }
71 
72     if (klass->device_plugged != NULL) {
73         klass->device_plugged(qbus->parent, &local_err);
74     }
75     if (local_err) {
76         error_propagate(errp, local_err);
77         return;
78     }
79 
80     if (klass->get_dma_as != NULL && has_iommu) {
81         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
82         vdev->dma_as = klass->get_dma_as(qbus->parent);
83     } else {
84         vdev->dma_as = &address_space_memory;
85     }
86 }
87 
88 /* Reset the virtio_bus */
89 void virtio_bus_reset(VirtioBusState *bus)
90 {
91     VirtIODevice *vdev = virtio_bus_get_device(bus);
92 
93     DPRINTF("%s: reset device.\n", BUS(bus)->name);
94     if (vdev != NULL) {
95         virtio_reset(vdev);
96     }
97 }
98 
99 /* A VirtIODevice is being unplugged */
100 void virtio_bus_device_unplugged(VirtIODevice *vdev)
101 {
102     DeviceState *qdev = DEVICE(vdev);
103     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
104     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
105 
106     DPRINTF("%s: remove device.\n", qbus->name);
107 
108     if (vdev != NULL) {
109         if (klass->device_unplugged != NULL) {
110             klass->device_unplugged(qbus->parent);
111         }
112     }
113 }
114 
115 /* Get the device id of the plugged device. */
116 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
117 {
118     VirtIODevice *vdev = virtio_bus_get_device(bus);
119     assert(vdev != NULL);
120     return vdev->device_id;
121 }
122 
123 /* Get the config_len field of the plugged device. */
124 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
125 {
126     VirtIODevice *vdev = virtio_bus_get_device(bus);
127     assert(vdev != NULL);
128     return vdev->config_len;
129 }
130 
131 /* Get bad features of the plugged device. */
132 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
133 {
134     VirtIODevice *vdev = virtio_bus_get_device(bus);
135     VirtioDeviceClass *k;
136 
137     assert(vdev != NULL);
138     k = VIRTIO_DEVICE_GET_CLASS(vdev);
139     if (k->bad_features != NULL) {
140         return k->bad_features(vdev);
141     } else {
142         return 0;
143     }
144 }
145 
146 /* Get config of the plugged device. */
147 void virtio_bus_get_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->get_config != NULL) {
155         k->get_config(vdev, config);
156     }
157 }
158 
159 /* Set config of the plugged device. */
160 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
161 {
162     VirtIODevice *vdev = virtio_bus_get_device(bus);
163     VirtioDeviceClass *k;
164 
165     assert(vdev != NULL);
166     k = VIRTIO_DEVICE_GET_CLASS(vdev);
167     if (k->set_config != NULL) {
168         k->set_config(vdev, config);
169     }
170 }
171 
172 /* On success, ioeventfd ownership belongs to the caller.  */
173 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
174 {
175     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
176 
177     /* vhost can be used even if ioeventfd=off in the proxy device,
178      * so do not check k->ioeventfd_enabled.
179      */
180     if (!k->ioeventfd_assign) {
181         return -ENOSYS;
182     }
183 
184     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
185         virtio_bus_stop_ioeventfd(bus);
186         /* Remember that we need to restart ioeventfd
187          * when ioeventfd_grabbed becomes zero.
188          */
189         bus->ioeventfd_started = true;
190     }
191     bus->ioeventfd_grabbed++;
192     return 0;
193 }
194 
195 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
196 {
197     assert(bus->ioeventfd_grabbed != 0);
198     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
199         /* Force virtio_bus_start_ioeventfd to act.  */
200         bus->ioeventfd_started = false;
201         virtio_bus_start_ioeventfd(bus);
202     }
203 }
204 
205 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
206 {
207     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
208     DeviceState *proxy = DEVICE(BUS(bus)->parent);
209     VirtIODevice *vdev = virtio_bus_get_device(bus);
210     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
211     int r;
212 
213     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
214         return -ENOSYS;
215     }
216     if (bus->ioeventfd_started) {
217         return 0;
218     }
219 
220     /* Only set our notifier if we have ownership.  */
221     if (!bus->ioeventfd_grabbed) {
222         r = vdc->start_ioeventfd(vdev);
223         if (r < 0) {
224             error_report("%s: failed. Fallback to userspace (slower).", __func__);
225             return r;
226         }
227     }
228     bus->ioeventfd_started = true;
229     return 0;
230 }
231 
232 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
233 {
234     VirtIODevice *vdev;
235     VirtioDeviceClass *vdc;
236 
237     if (!bus->ioeventfd_started) {
238         return;
239     }
240 
241     /* Only remove our notifier if we have ownership.  */
242     if (!bus->ioeventfd_grabbed) {
243         vdev = virtio_bus_get_device(bus);
244         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
245         vdc->stop_ioeventfd(vdev);
246     }
247     bus->ioeventfd_started = false;
248 }
249 
250 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
251 {
252     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
253     DeviceState *proxy = DEVICE(BUS(bus)->parent);
254 
255     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
256 }
257 
258 /*
259  * This function switches ioeventfd on/off in the device.
260  * The caller must set or clear the handlers for the EventNotifier.
261  */
262 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
263 {
264     VirtIODevice *vdev = virtio_bus_get_device(bus);
265     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
266     DeviceState *proxy = DEVICE(BUS(bus)->parent);
267     VirtQueue *vq = virtio_get_queue(vdev, n);
268     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
269     int r = 0;
270 
271     if (!k->ioeventfd_assign) {
272         return -ENOSYS;
273     }
274 
275     if (assign) {
276         r = event_notifier_init(notifier, 1);
277         if (r < 0) {
278             error_report("%s: unable to init event notifier: %s (%d)",
279                          __func__, strerror(-r), r);
280             return r;
281         }
282         r = k->ioeventfd_assign(proxy, notifier, n, true);
283         if (r < 0) {
284             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
285             virtio_bus_cleanup_host_notifier(bus, n);
286         }
287     } else {
288         k->ioeventfd_assign(proxy, notifier, n, false);
289     }
290 
291     return r;
292 }
293 
294 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
295 {
296     VirtIODevice *vdev = virtio_bus_get_device(bus);
297     VirtQueue *vq = virtio_get_queue(vdev, n);
298     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
299 
300     /* Test and clear notifier after disabling event,
301      * in case poll callback didn't have time to run.
302      */
303     virtio_queue_host_notifier_read(notifier);
304     event_notifier_cleanup(notifier);
305 }
306 
307 static char *virtio_bus_get_dev_path(DeviceState *dev)
308 {
309     BusState *bus = qdev_get_parent_bus(dev);
310     DeviceState *proxy = DEVICE(bus->parent);
311     return qdev_get_dev_path(proxy);
312 }
313 
314 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
315 {
316     return NULL;
317 }
318 
319 static void virtio_bus_class_init(ObjectClass *klass, void *data)
320 {
321     BusClass *bus_class = BUS_CLASS(klass);
322     bus_class->get_dev_path = virtio_bus_get_dev_path;
323     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
324 }
325 
326 static const TypeInfo virtio_bus_info = {
327     .name = TYPE_VIRTIO_BUS,
328     .parent = TYPE_BUS,
329     .instance_size = sizeof(VirtioBusState),
330     .abstract = true,
331     .class_size = sizeof(VirtioBusClass),
332     .class_init = virtio_bus_class_init
333 };
334 
335 static void virtio_register_types(void)
336 {
337     type_register_static(&virtio_bus_info);
338 }
339 
340 type_init(virtio_register_types)
341