xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision aadfe320) 
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     bool vdev_has_iommu;
52     Error *local_err = NULL;
53 
54     DPRINTF("%s: plug device.\n", qbus->name);
55 
56     if (klass->pre_plugged != NULL) {
57         klass->pre_plugged(qbus->parent, &local_err);
58         if (local_err) {
59             error_propagate(errp, local_err);
60             return;
61         }
62     }
63 
64     /* Get the features of the plugged device. */
65     assert(vdc->get_features != NULL);
66     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
67                                             &local_err);
68     if (local_err) {
69         error_propagate(errp, local_err);
70         return;
71     }
72 
73     if (klass->device_plugged != NULL) {
74         klass->device_plugged(qbus->parent, &local_err);
75     }
76     if (local_err) {
77         error_propagate(errp, local_err);
78         return;
79     }
80 
81     vdev->dma_as = &address_space_memory;
82     if (has_iommu) {
83         vdev_has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
84         /*
85          * Present IOMMU_PLATFORM to the driver iff iommu_plattform=on and
86          * device operational. If the driver does not accept IOMMU_PLATFORM
87          * we fail the device.
88          */
89         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
90         if (klass->get_dma_as) {
91             vdev->dma_as = klass->get_dma_as(qbus->parent);
92             if (!vdev_has_iommu && vdev->dma_as != &address_space_memory) {
93                 error_setg(errp,
94                        "iommu_platform=true is not supported by the device");
95                 return;
96             }
97         }
98     }
99 }
100 
101 /* Reset the virtio_bus */
102 void virtio_bus_reset(VirtioBusState *bus)
103 {
104     VirtIODevice *vdev = virtio_bus_get_device(bus);
105 
106     DPRINTF("%s: reset device.\n", BUS(bus)->name);
107     if (vdev != NULL) {
108         virtio_reset(vdev);
109     }
110 }
111 
112 /* A VirtIODevice is being unplugged */
113 void virtio_bus_device_unplugged(VirtIODevice *vdev)
114 {
115     DeviceState *qdev = DEVICE(vdev);
116     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
117     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
118 
119     DPRINTF("%s: remove device.\n", qbus->name);
120 
121     if (vdev != NULL) {
122         if (klass->device_unplugged != NULL) {
123             klass->device_unplugged(qbus->parent);
124         }
125     }
126 }
127 
128 /* Get the device id of the plugged device. */
129 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
130 {
131     VirtIODevice *vdev = virtio_bus_get_device(bus);
132     assert(vdev != NULL);
133     return vdev->device_id;
134 }
135 
136 /* Get the config_len field of the plugged device. */
137 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
138 {
139     VirtIODevice *vdev = virtio_bus_get_device(bus);
140     assert(vdev != NULL);
141     return vdev->config_len;
142 }
143 
144 /* Get bad features of the plugged device. */
145 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
146 {
147     VirtIODevice *vdev = virtio_bus_get_device(bus);
148     VirtioDeviceClass *k;
149 
150     assert(vdev != NULL);
151     k = VIRTIO_DEVICE_GET_CLASS(vdev);
152     if (k->bad_features != NULL) {
153         return k->bad_features(vdev);
154     } else {
155         return 0;
156     }
157 }
158 
159 /* Get config of the plugged device. */
160 void virtio_bus_get_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->get_config != NULL) {
168         k->get_config(vdev, config);
169     }
170 }
171 
172 /* Set config of the plugged device. */
173 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
174 {
175     VirtIODevice *vdev = virtio_bus_get_device(bus);
176     VirtioDeviceClass *k;
177 
178     assert(vdev != NULL);
179     k = VIRTIO_DEVICE_GET_CLASS(vdev);
180     if (k->set_config != NULL) {
181         k->set_config(vdev, config);
182     }
183 }
184 
185 /* On success, ioeventfd ownership belongs to the caller.  */
186 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
187 {
188     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
189 
190     /* vhost can be used even if ioeventfd=off in the proxy device,
191      * so do not check k->ioeventfd_enabled.
192      */
193     if (!k->ioeventfd_assign) {
194         return -ENOSYS;
195     }
196 
197     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
198         virtio_bus_stop_ioeventfd(bus);
199         /* Remember that we need to restart ioeventfd
200          * when ioeventfd_grabbed becomes zero.
201          */
202         bus->ioeventfd_started = true;
203     }
204     bus->ioeventfd_grabbed++;
205     return 0;
206 }
207 
208 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
209 {
210     assert(bus->ioeventfd_grabbed != 0);
211     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
212         /* Force virtio_bus_start_ioeventfd to act.  */
213         bus->ioeventfd_started = false;
214         virtio_bus_start_ioeventfd(bus);
215     }
216 }
217 
218 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
219 {
220     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
221     DeviceState *proxy = DEVICE(BUS(bus)->parent);
222     VirtIODevice *vdev = virtio_bus_get_device(bus);
223     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
224     int r;
225 
226     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
227         return -ENOSYS;
228     }
229     if (bus->ioeventfd_started) {
230         return 0;
231     }
232 
233     /* Only set our notifier if we have ownership.  */
234     if (!bus->ioeventfd_grabbed) {
235         r = vdc->start_ioeventfd(vdev);
236         if (r < 0) {
237             error_report("%s: failed. Fallback to userspace (slower).", __func__);
238             return r;
239         }
240     }
241     bus->ioeventfd_started = true;
242     return 0;
243 }
244 
245 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
246 {
247     VirtIODevice *vdev;
248     VirtioDeviceClass *vdc;
249 
250     if (!bus->ioeventfd_started) {
251         return;
252     }
253 
254     /* Only remove our notifier if we have ownership.  */
255     if (!bus->ioeventfd_grabbed) {
256         vdev = virtio_bus_get_device(bus);
257         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
258         vdc->stop_ioeventfd(vdev);
259     }
260     bus->ioeventfd_started = false;
261 }
262 
263 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
264 {
265     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
266     DeviceState *proxy = DEVICE(BUS(bus)->parent);
267 
268     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
269 }
270 
271 /*
272  * This function switches ioeventfd on/off in the device.
273  * The caller must set or clear the handlers for the EventNotifier.
274  */
275 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
276 {
277     VirtIODevice *vdev = virtio_bus_get_device(bus);
278     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
279     DeviceState *proxy = DEVICE(BUS(bus)->parent);
280     VirtQueue *vq = virtio_get_queue(vdev, n);
281     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
282     int r = 0;
283 
284     if (!k->ioeventfd_assign) {
285         return -ENOSYS;
286     }
287 
288     if (assign) {
289         r = event_notifier_init(notifier, 1);
290         if (r < 0) {
291             error_report("%s: unable to init event notifier: %s (%d)",
292                          __func__, strerror(-r), r);
293             return r;
294         }
295         r = k->ioeventfd_assign(proxy, notifier, n, true);
296         if (r < 0) {
297             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
298             virtio_bus_cleanup_host_notifier(bus, n);
299         }
300     } else {
301         k->ioeventfd_assign(proxy, notifier, n, false);
302     }
303 
304     if (r == 0) {
305         virtio_queue_set_host_notifier_enabled(vq, assign);
306     }
307 
308     return r;
309 }
310 
311 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
312 {
313     VirtIODevice *vdev = virtio_bus_get_device(bus);
314     VirtQueue *vq = virtio_get_queue(vdev, n);
315     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
316 
317     /* Test and clear notifier after disabling event,
318      * in case poll callback didn't have time to run.
319      */
320     virtio_queue_host_notifier_read(notifier);
321     event_notifier_cleanup(notifier);
322 }
323 
324 static char *virtio_bus_get_dev_path(DeviceState *dev)
325 {
326     BusState *bus = qdev_get_parent_bus(dev);
327     DeviceState *proxy = DEVICE(bus->parent);
328     return qdev_get_dev_path(proxy);
329 }
330 
331 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
332 {
333     return NULL;
334 }
335 
336 bool virtio_bus_device_iommu_enabled(VirtIODevice *vdev)
337 {
338     DeviceState *qdev = DEVICE(vdev);
339     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
340     VirtioBusState *bus = VIRTIO_BUS(qbus);
341     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
342 
343     if (!klass->iommu_enabled) {
344         return false;
345     }
346 
347     return klass->iommu_enabled(qbus->parent);
348 }
349 
350 static void virtio_bus_class_init(ObjectClass *klass, void *data)
351 {
352     BusClass *bus_class = BUS_CLASS(klass);
353     bus_class->get_dev_path = virtio_bus_get_dev_path;
354     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
355 }
356 
357 static const TypeInfo virtio_bus_info = {
358     .name = TYPE_VIRTIO_BUS,
359     .parent = TYPE_BUS,
360     .instance_size = sizeof(VirtioBusState),
361     .abstract = true,
362     .class_size = sizeof(VirtioBusClass),
363     .class_init = virtio_bus_class_init
364 };
365 
366 static void virtio_register_types(void)
367 {
368     type_register_static(&virtio_bus_info);
369 }
370 
371 type_init(virtio_register_types)
372