xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision 500eb6db) 
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 "qemu/module.h"
29 #include "qapi/error.h"
30 #include "hw/qdev.h"
31 #include "hw/virtio/virtio-bus.h"
32 #include "hw/virtio/virtio.h"
33 #include "exec/address-spaces.h"
34 
35 /* #define DEBUG_VIRTIO_BUS */
36 
37 #ifdef DEBUG_VIRTIO_BUS
38 #define DPRINTF(fmt, ...) \
39 do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
40 #else
41 #define DPRINTF(fmt, ...) do { } while (0)
42 #endif
43 
44 /* A VirtIODevice is being plugged */
45 void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
46 {
47     DeviceState *qdev = DEVICE(vdev);
48     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
49     VirtioBusState *bus = VIRTIO_BUS(qbus);
50     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
51     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
52     bool has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
53     Error *local_err = NULL;
54 
55     DPRINTF("%s: plug device.\n", qbus->name);
56 
57     if (klass->pre_plugged != NULL) {
58         klass->pre_plugged(qbus->parent, &local_err);
59         if (local_err) {
60             error_propagate(errp, local_err);
61             return;
62         }
63     }
64 
65     /* Get the features of the plugged device. */
66     assert(vdc->get_features != NULL);
67     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
68                                             &local_err);
69     if (local_err) {
70         error_propagate(errp, local_err);
71         return;
72     }
73 
74     if (klass->device_plugged != NULL) {
75         klass->device_plugged(qbus->parent, &local_err);
76     }
77     if (local_err) {
78         error_propagate(errp, local_err);
79         return;
80     }
81 
82     if (klass->get_dma_as != NULL && has_iommu) {
83         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
84         vdev->dma_as = klass->get_dma_as(qbus->parent);
85     } else {
86         vdev->dma_as = &address_space_memory;
87     }
88 }
89 
90 /* Reset the virtio_bus */
91 void virtio_bus_reset(VirtioBusState *bus)
92 {
93     VirtIODevice *vdev = virtio_bus_get_device(bus);
94 
95     DPRINTF("%s: reset device.\n", BUS(bus)->name);
96     if (vdev != NULL) {
97         virtio_reset(vdev);
98     }
99 }
100 
101 /* A VirtIODevice is being unplugged */
102 void virtio_bus_device_unplugged(VirtIODevice *vdev)
103 {
104     DeviceState *qdev = DEVICE(vdev);
105     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
106     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
107 
108     DPRINTF("%s: remove device.\n", qbus->name);
109 
110     if (vdev != NULL) {
111         if (klass->device_unplugged != NULL) {
112             klass->device_unplugged(qbus->parent);
113         }
114     }
115 }
116 
117 /* Get the device id of the plugged device. */
118 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
119 {
120     VirtIODevice *vdev = virtio_bus_get_device(bus);
121     assert(vdev != NULL);
122     return vdev->device_id;
123 }
124 
125 /* Get the config_len field of the plugged device. */
126 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
127 {
128     VirtIODevice *vdev = virtio_bus_get_device(bus);
129     assert(vdev != NULL);
130     return vdev->config_len;
131 }
132 
133 /* Get bad features of the plugged device. */
134 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
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->bad_features != NULL) {
142         return k->bad_features(vdev);
143     } else {
144         return 0;
145     }
146 }
147 
148 /* Get config of the plugged device. */
149 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
150 {
151     VirtIODevice *vdev = virtio_bus_get_device(bus);
152     VirtioDeviceClass *k;
153 
154     assert(vdev != NULL);
155     k = VIRTIO_DEVICE_GET_CLASS(vdev);
156     if (k->get_config != NULL) {
157         k->get_config(vdev, config);
158     }
159 }
160 
161 /* Set config of the plugged device. */
162 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
163 {
164     VirtIODevice *vdev = virtio_bus_get_device(bus);
165     VirtioDeviceClass *k;
166 
167     assert(vdev != NULL);
168     k = VIRTIO_DEVICE_GET_CLASS(vdev);
169     if (k->set_config != NULL) {
170         k->set_config(vdev, config);
171     }
172 }
173 
174 /* On success, ioeventfd ownership belongs to the caller.  */
175 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
176 {
177     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
178 
179     /* vhost can be used even if ioeventfd=off in the proxy device,
180      * so do not check k->ioeventfd_enabled.
181      */
182     if (!k->ioeventfd_assign) {
183         return -ENOSYS;
184     }
185 
186     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
187         virtio_bus_stop_ioeventfd(bus);
188         /* Remember that we need to restart ioeventfd
189          * when ioeventfd_grabbed becomes zero.
190          */
191         bus->ioeventfd_started = true;
192     }
193     bus->ioeventfd_grabbed++;
194     return 0;
195 }
196 
197 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
198 {
199     assert(bus->ioeventfd_grabbed != 0);
200     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
201         /* Force virtio_bus_start_ioeventfd to act.  */
202         bus->ioeventfd_started = false;
203         virtio_bus_start_ioeventfd(bus);
204     }
205 }
206 
207 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
208 {
209     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
210     DeviceState *proxy = DEVICE(BUS(bus)->parent);
211     VirtIODevice *vdev = virtio_bus_get_device(bus);
212     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
213     int r;
214 
215     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
216         return -ENOSYS;
217     }
218     if (bus->ioeventfd_started) {
219         return 0;
220     }
221 
222     /* Only set our notifier if we have ownership.  */
223     if (!bus->ioeventfd_grabbed) {
224         r = vdc->start_ioeventfd(vdev);
225         if (r < 0) {
226             error_report("%s: failed. Fallback to userspace (slower).", __func__);
227             return r;
228         }
229     }
230     bus->ioeventfd_started = true;
231     return 0;
232 }
233 
234 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
235 {
236     VirtIODevice *vdev;
237     VirtioDeviceClass *vdc;
238 
239     if (!bus->ioeventfd_started) {
240         return;
241     }
242 
243     /* Only remove our notifier if we have ownership.  */
244     if (!bus->ioeventfd_grabbed) {
245         vdev = virtio_bus_get_device(bus);
246         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
247         vdc->stop_ioeventfd(vdev);
248     }
249     bus->ioeventfd_started = false;
250 }
251 
252 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
253 {
254     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
255     DeviceState *proxy = DEVICE(BUS(bus)->parent);
256 
257     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
258 }
259 
260 /*
261  * This function switches ioeventfd on/off in the device.
262  * The caller must set or clear the handlers for the EventNotifier.
263  */
264 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
265 {
266     VirtIODevice *vdev = virtio_bus_get_device(bus);
267     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
268     DeviceState *proxy = DEVICE(BUS(bus)->parent);
269     VirtQueue *vq = virtio_get_queue(vdev, n);
270     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
271     int r = 0;
272 
273     if (!k->ioeventfd_assign) {
274         return -ENOSYS;
275     }
276 
277     if (assign) {
278         r = event_notifier_init(notifier, 1);
279         if (r < 0) {
280             error_report("%s: unable to init event notifier: %s (%d)",
281                          __func__, strerror(-r), r);
282             return r;
283         }
284         r = k->ioeventfd_assign(proxy, notifier, n, true);
285         if (r < 0) {
286             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
287             virtio_bus_cleanup_host_notifier(bus, n);
288         }
289     } else {
290         k->ioeventfd_assign(proxy, notifier, n, false);
291     }
292 
293     return r;
294 }
295 
296 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
297 {
298     VirtIODevice *vdev = virtio_bus_get_device(bus);
299     VirtQueue *vq = virtio_get_queue(vdev, n);
300     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
301 
302     /* Test and clear notifier after disabling event,
303      * in case poll callback didn't have time to run.
304      */
305     virtio_queue_host_notifier_read(notifier);
306     event_notifier_cleanup(notifier);
307 }
308 
309 static char *virtio_bus_get_dev_path(DeviceState *dev)
310 {
311     BusState *bus = qdev_get_parent_bus(dev);
312     DeviceState *proxy = DEVICE(bus->parent);
313     return qdev_get_dev_path(proxy);
314 }
315 
316 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
317 {
318     return NULL;
319 }
320 
321 static void virtio_bus_class_init(ObjectClass *klass, void *data)
322 {
323     BusClass *bus_class = BUS_CLASS(klass);
324     bus_class->get_dev_path = virtio_bus_get_dev_path;
325     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
326 }
327 
328 static const TypeInfo virtio_bus_info = {
329     .name = TYPE_VIRTIO_BUS,
330     .parent = TYPE_BUS,
331     .instance_size = sizeof(VirtioBusState),
332     .abstract = true,
333     .class_size = sizeof(VirtioBusClass),
334     .class_init = virtio_bus_class_init
335 };
336 
337 static void virtio_register_types(void)
338 {
339     type_register_static(&virtio_bus_info);
340 }
341 
342 type_init(virtio_register_types)
343