xref: /qemu/hw/virtio/virtio-bus.c (revision 336d354b) 
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_has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
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         if (!vdev_has_iommu && vdev->dma_as != &address_space_memory) {
86             error_setg(errp,
87                        "iommu_platform=true is not supported by the device");
88             return;
89         }
90     } else {
91         vdev->dma_as = &address_space_memory;
92     }
93 }
94 
95 /* Reset the virtio_bus */
96 void virtio_bus_reset(VirtioBusState *bus)
97 {
98     VirtIODevice *vdev = virtio_bus_get_device(bus);
99 
100     DPRINTF("%s: reset device.\n", BUS(bus)->name);
101     if (vdev != NULL) {
102         virtio_reset(vdev);
103     }
104 }
105 
106 /* A VirtIODevice is being unplugged */
107 void virtio_bus_device_unplugged(VirtIODevice *vdev)
108 {
109     DeviceState *qdev = DEVICE(vdev);
110     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
111     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
112 
113     DPRINTF("%s: remove device.\n", qbus->name);
114 
115     if (vdev != NULL) {
116         if (klass->device_unplugged != NULL) {
117             klass->device_unplugged(qbus->parent);
118         }
119     }
120 }
121 
122 /* Get the device id of the plugged device. */
123 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
124 {
125     VirtIODevice *vdev = virtio_bus_get_device(bus);
126     assert(vdev != NULL);
127     return vdev->device_id;
128 }
129 
130 /* Get the config_len field of the plugged device. */
131 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
132 {
133     VirtIODevice *vdev = virtio_bus_get_device(bus);
134     assert(vdev != NULL);
135     return vdev->config_len;
136 }
137 
138 /* Get bad features of the plugged device. */
139 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
140 {
141     VirtIODevice *vdev = virtio_bus_get_device(bus);
142     VirtioDeviceClass *k;
143 
144     assert(vdev != NULL);
145     k = VIRTIO_DEVICE_GET_CLASS(vdev);
146     if (k->bad_features != NULL) {
147         return k->bad_features(vdev);
148     } else {
149         return 0;
150     }
151 }
152 
153 /* Get config of the plugged device. */
154 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
155 {
156     VirtIODevice *vdev = virtio_bus_get_device(bus);
157     VirtioDeviceClass *k;
158 
159     assert(vdev != NULL);
160     k = VIRTIO_DEVICE_GET_CLASS(vdev);
161     if (k->get_config != NULL) {
162         k->get_config(vdev, config);
163     }
164 }
165 
166 /* Set config of the plugged device. */
167 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
168 {
169     VirtIODevice *vdev = virtio_bus_get_device(bus);
170     VirtioDeviceClass *k;
171 
172     assert(vdev != NULL);
173     k = VIRTIO_DEVICE_GET_CLASS(vdev);
174     if (k->set_config != NULL) {
175         k->set_config(vdev, config);
176     }
177 }
178 
179 /* On success, ioeventfd ownership belongs to the caller.  */
180 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
181 {
182     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
183 
184     /* vhost can be used even if ioeventfd=off in the proxy device,
185      * so do not check k->ioeventfd_enabled.
186      */
187     if (!k->ioeventfd_assign) {
188         return -ENOSYS;
189     }
190 
191     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
192         virtio_bus_stop_ioeventfd(bus);
193         /* Remember that we need to restart ioeventfd
194          * when ioeventfd_grabbed becomes zero.
195          */
196         bus->ioeventfd_started = true;
197     }
198     bus->ioeventfd_grabbed++;
199     return 0;
200 }
201 
202 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
203 {
204     assert(bus->ioeventfd_grabbed != 0);
205     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
206         /* Force virtio_bus_start_ioeventfd to act.  */
207         bus->ioeventfd_started = false;
208         virtio_bus_start_ioeventfd(bus);
209     }
210 }
211 
212 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
213 {
214     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
215     DeviceState *proxy = DEVICE(BUS(bus)->parent);
216     VirtIODevice *vdev = virtio_bus_get_device(bus);
217     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
218     int r;
219 
220     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
221         return -ENOSYS;
222     }
223     if (bus->ioeventfd_started) {
224         return 0;
225     }
226 
227     /* Only set our notifier if we have ownership.  */
228     if (!bus->ioeventfd_grabbed) {
229         r = vdc->start_ioeventfd(vdev);
230         if (r < 0) {
231             error_report("%s: failed. Fallback to userspace (slower).", __func__);
232             return r;
233         }
234     }
235     bus->ioeventfd_started = true;
236     return 0;
237 }
238 
239 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
240 {
241     VirtIODevice *vdev;
242     VirtioDeviceClass *vdc;
243 
244     if (!bus->ioeventfd_started) {
245         return;
246     }
247 
248     /* Only remove our notifier if we have ownership.  */
249     if (!bus->ioeventfd_grabbed) {
250         vdev = virtio_bus_get_device(bus);
251         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
252         vdc->stop_ioeventfd(vdev);
253     }
254     bus->ioeventfd_started = false;
255 }
256 
257 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
258 {
259     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
260     DeviceState *proxy = DEVICE(BUS(bus)->parent);
261 
262     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
263 }
264 
265 /*
266  * This function switches ioeventfd on/off in the device.
267  * The caller must set or clear the handlers for the EventNotifier.
268  */
269 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
270 {
271     VirtIODevice *vdev = virtio_bus_get_device(bus);
272     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
273     DeviceState *proxy = DEVICE(BUS(bus)->parent);
274     VirtQueue *vq = virtio_get_queue(vdev, n);
275     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
276     int r = 0;
277 
278     if (!k->ioeventfd_assign) {
279         return -ENOSYS;
280     }
281 
282     if (assign) {
283         r = event_notifier_init(notifier, 1);
284         if (r < 0) {
285             error_report("%s: unable to init event notifier: %s (%d)",
286                          __func__, strerror(-r), r);
287             return r;
288         }
289         r = k->ioeventfd_assign(proxy, notifier, n, true);
290         if (r < 0) {
291             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
292             virtio_bus_cleanup_host_notifier(bus, n);
293         }
294     } else {
295         k->ioeventfd_assign(proxy, notifier, n, false);
296     }
297 
298     if (r == 0) {
299         virtio_queue_set_host_notifier_enabled(vq, assign);
300     }
301 
302     return r;
303 }
304 
305 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
306 {
307     VirtIODevice *vdev = virtio_bus_get_device(bus);
308     VirtQueue *vq = virtio_get_queue(vdev, n);
309     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
310 
311     /* Test and clear notifier after disabling event,
312      * in case poll callback didn't have time to run.
313      */
314     virtio_queue_host_notifier_read(notifier);
315     event_notifier_cleanup(notifier);
316 }
317 
318 static char *virtio_bus_get_dev_path(DeviceState *dev)
319 {
320     BusState *bus = qdev_get_parent_bus(dev);
321     DeviceState *proxy = DEVICE(bus->parent);
322     return qdev_get_dev_path(proxy);
323 }
324 
325 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
326 {
327     return NULL;
328 }
329 
330 bool virtio_bus_device_iommu_enabled(VirtIODevice *vdev)
331 {
332     DeviceState *qdev = DEVICE(vdev);
333     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
334     VirtioBusState *bus = VIRTIO_BUS(qbus);
335     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
336 
337     if (!klass->iommu_enabled) {
338         return false;
339     }
340 
341     return klass->iommu_enabled(qbus->parent);
342 }
343 
344 static void virtio_bus_class_init(ObjectClass *klass, void *data)
345 {
346     BusClass *bus_class = BUS_CLASS(klass);
347     bus_class->get_dev_path = virtio_bus_get_dev_path;
348     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
349 }
350 
351 static const TypeInfo virtio_bus_info = {
352     .name = TYPE_VIRTIO_BUS,
353     .parent = TYPE_BUS,
354     .instance_size = sizeof(VirtioBusState),
355     .abstract = true,
356     .class_size = sizeof(VirtioBusClass),
357     .class_init = virtio_bus_class_init
358 };
359 
360 static void virtio_register_types(void)
361 {
362     type_register_static(&virtio_bus_info);
363 }
364 
365 type_init(virtio_register_types)
366