xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision be05216b) 
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 (has_iommu && !virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
73         error_setg(errp, "iommu_platform=true is not supported by the device");
74         return;
75     }
76 
77     if (klass->device_plugged != NULL) {
78         klass->device_plugged(qbus->parent, &local_err);
79     }
80     if (local_err) {
81         error_propagate(errp, local_err);
82         return;
83     }
84 
85     if (klass->get_dma_as != NULL && has_iommu) {
86         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
87         vdev->dma_as = klass->get_dma_as(qbus->parent);
88     } else {
89         vdev->dma_as = &address_space_memory;
90     }
91 }
92 
93 /* Reset the virtio_bus */
94 void virtio_bus_reset(VirtioBusState *bus)
95 {
96     VirtIODevice *vdev = virtio_bus_get_device(bus);
97 
98     DPRINTF("%s: reset device.\n", BUS(bus)->name);
99     if (vdev != NULL) {
100         virtio_reset(vdev);
101     }
102 }
103 
104 /* A VirtIODevice is being unplugged */
105 void virtio_bus_device_unplugged(VirtIODevice *vdev)
106 {
107     DeviceState *qdev = DEVICE(vdev);
108     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
109     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
110 
111     DPRINTF("%s: remove device.\n", qbus->name);
112 
113     if (vdev != NULL) {
114         if (klass->device_unplugged != NULL) {
115             klass->device_unplugged(qbus->parent);
116         }
117     }
118 }
119 
120 /* Get the device id of the plugged device. */
121 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
122 {
123     VirtIODevice *vdev = virtio_bus_get_device(bus);
124     assert(vdev != NULL);
125     return vdev->device_id;
126 }
127 
128 /* Get the config_len field of the plugged device. */
129 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
130 {
131     VirtIODevice *vdev = virtio_bus_get_device(bus);
132     assert(vdev != NULL);
133     return vdev->config_len;
134 }
135 
136 /* Get bad features of the plugged device. */
137 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
138 {
139     VirtIODevice *vdev = virtio_bus_get_device(bus);
140     VirtioDeviceClass *k;
141 
142     assert(vdev != NULL);
143     k = VIRTIO_DEVICE_GET_CLASS(vdev);
144     if (k->bad_features != NULL) {
145         return k->bad_features(vdev);
146     } else {
147         return 0;
148     }
149 }
150 
151 /* Get config of the plugged device. */
152 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
153 {
154     VirtIODevice *vdev = virtio_bus_get_device(bus);
155     VirtioDeviceClass *k;
156 
157     assert(vdev != NULL);
158     k = VIRTIO_DEVICE_GET_CLASS(vdev);
159     if (k->get_config != NULL) {
160         k->get_config(vdev, config);
161     }
162 }
163 
164 /* Set config of the plugged device. */
165 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
166 {
167     VirtIODevice *vdev = virtio_bus_get_device(bus);
168     VirtioDeviceClass *k;
169 
170     assert(vdev != NULL);
171     k = VIRTIO_DEVICE_GET_CLASS(vdev);
172     if (k->set_config != NULL) {
173         k->set_config(vdev, config);
174     }
175 }
176 
177 /* On success, ioeventfd ownership belongs to the caller.  */
178 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
179 {
180     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
181 
182     /* vhost can be used even if ioeventfd=off in the proxy device,
183      * so do not check k->ioeventfd_enabled.
184      */
185     if (!k->ioeventfd_assign) {
186         return -ENOSYS;
187     }
188 
189     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
190         virtio_bus_stop_ioeventfd(bus);
191         /* Remember that we need to restart ioeventfd
192          * when ioeventfd_grabbed becomes zero.
193          */
194         bus->ioeventfd_started = true;
195     }
196     bus->ioeventfd_grabbed++;
197     return 0;
198 }
199 
200 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
201 {
202     assert(bus->ioeventfd_grabbed != 0);
203     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
204         /* Force virtio_bus_start_ioeventfd to act.  */
205         bus->ioeventfd_started = false;
206         virtio_bus_start_ioeventfd(bus);
207     }
208 }
209 
210 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
211 {
212     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
213     DeviceState *proxy = DEVICE(BUS(bus)->parent);
214     VirtIODevice *vdev = virtio_bus_get_device(bus);
215     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
216     int r;
217 
218     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
219         return -ENOSYS;
220     }
221     if (bus->ioeventfd_started) {
222         return 0;
223     }
224 
225     /* Only set our notifier if we have ownership.  */
226     if (!bus->ioeventfd_grabbed) {
227         r = vdc->start_ioeventfd(vdev);
228         if (r < 0) {
229             error_report("%s: failed. Fallback to userspace (slower).", __func__);
230             return r;
231         }
232     }
233     bus->ioeventfd_started = true;
234     return 0;
235 }
236 
237 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
238 {
239     VirtIODevice *vdev;
240     VirtioDeviceClass *vdc;
241 
242     if (!bus->ioeventfd_started) {
243         return;
244     }
245 
246     /* Only remove our notifier if we have ownership.  */
247     if (!bus->ioeventfd_grabbed) {
248         vdev = virtio_bus_get_device(bus);
249         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
250         vdc->stop_ioeventfd(vdev);
251     }
252     bus->ioeventfd_started = false;
253 }
254 
255 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
256 {
257     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
258     DeviceState *proxy = DEVICE(BUS(bus)->parent);
259 
260     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
261 }
262 
263 /*
264  * This function switches ioeventfd on/off in the device.
265  * The caller must set or clear the handlers for the EventNotifier.
266  */
267 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
268 {
269     VirtIODevice *vdev = virtio_bus_get_device(bus);
270     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
271     DeviceState *proxy = DEVICE(BUS(bus)->parent);
272     VirtQueue *vq = virtio_get_queue(vdev, n);
273     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
274     int r = 0;
275 
276     if (!k->ioeventfd_assign) {
277         return -ENOSYS;
278     }
279 
280     if (assign) {
281         r = event_notifier_init(notifier, 1);
282         if (r < 0) {
283             error_report("%s: unable to init event notifier: %s (%d)",
284                          __func__, strerror(-r), r);
285             return r;
286         }
287         r = k->ioeventfd_assign(proxy, notifier, n, true);
288         if (r < 0) {
289             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
290             virtio_bus_cleanup_host_notifier(bus, n);
291         }
292     } else {
293         k->ioeventfd_assign(proxy, notifier, n, false);
294     }
295 
296     if (r == 0) {
297         virtio_queue_set_host_notifier_enabled(vq, assign);
298     }
299 
300     return r;
301 }
302 
303 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
304 {
305     VirtIODevice *vdev = virtio_bus_get_device(bus);
306     VirtQueue *vq = virtio_get_queue(vdev, n);
307     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
308 
309     /* Test and clear notifier after disabling event,
310      * in case poll callback didn't have time to run.
311      */
312     virtio_queue_host_notifier_read(notifier);
313     event_notifier_cleanup(notifier);
314 }
315 
316 static char *virtio_bus_get_dev_path(DeviceState *dev)
317 {
318     BusState *bus = qdev_get_parent_bus(dev);
319     DeviceState *proxy = DEVICE(bus->parent);
320     return qdev_get_dev_path(proxy);
321 }
322 
323 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
324 {
325     return NULL;
326 }
327 
328 static void virtio_bus_class_init(ObjectClass *klass, void *data)
329 {
330     BusClass *bus_class = BUS_CLASS(klass);
331     bus_class->get_dev_path = virtio_bus_get_dev_path;
332     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
333 }
334 
335 static const TypeInfo virtio_bus_info = {
336     .name = TYPE_VIRTIO_BUS,
337     .parent = TYPE_BUS,
338     .instance_size = sizeof(VirtioBusState),
339     .abstract = true,
340     .class_size = sizeof(VirtioBusClass),
341     .class_init = virtio_bus_class_init
342 };
343 
344 static void virtio_register_types(void)
345 {
346     type_register_static(&virtio_bus_info);
347 }
348 
349 type_init(virtio_register_types)
350