xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision 4fe6d78b) 
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 "qapi/error.h"
29 #include "hw/qdev.h"
30 #include "hw/virtio/virtio-bus.h"
31 #include "hw/virtio/virtio.h"
32 #include "exec/address-spaces.h"
33 
34 /* #define DEBUG_VIRTIO_BUS */
35 
36 #ifdef DEBUG_VIRTIO_BUS
37 #define DPRINTF(fmt, ...) \
38 do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
39 #else
40 #define DPRINTF(fmt, ...) do { } while (0)
41 #endif
42 
43 /* A VirtIODevice is being plugged */
44 void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
45 {
46     DeviceState *qdev = DEVICE(vdev);
47     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
48     VirtioBusState *bus = VIRTIO_BUS(qbus);
49     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
50     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
51     bool has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
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     if (klass->get_dma_as != NULL && has_iommu) {
82         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
83         vdev->dma_as = klass->get_dma_as(qbus->parent);
84     } else {
85         vdev->dma_as = &address_space_memory;
86     }
87 }
88 
89 /* Reset the virtio_bus */
90 void virtio_bus_reset(VirtioBusState *bus)
91 {
92     VirtIODevice *vdev = virtio_bus_get_device(bus);
93 
94     DPRINTF("%s: reset device.\n", BUS(bus)->name);
95     if (vdev != NULL) {
96         virtio_reset(vdev);
97     }
98 }
99 
100 /* A VirtIODevice is being unplugged */
101 void virtio_bus_device_unplugged(VirtIODevice *vdev)
102 {
103     DeviceState *qdev = DEVICE(vdev);
104     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
105     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
106 
107     DPRINTF("%s: remove device.\n", qbus->name);
108 
109     if (vdev != NULL) {
110         if (klass->device_unplugged != NULL) {
111             klass->device_unplugged(qbus->parent);
112         }
113     }
114 }
115 
116 /* Get the device id of the plugged device. */
117 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
118 {
119     VirtIODevice *vdev = virtio_bus_get_device(bus);
120     assert(vdev != NULL);
121     return vdev->device_id;
122 }
123 
124 /* Get the config_len field of the plugged device. */
125 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
126 {
127     VirtIODevice *vdev = virtio_bus_get_device(bus);
128     assert(vdev != NULL);
129     return vdev->config_len;
130 }
131 
132 /* Get bad features of the plugged device. */
133 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
134 {
135     VirtIODevice *vdev = virtio_bus_get_device(bus);
136     VirtioDeviceClass *k;
137 
138     assert(vdev != NULL);
139     k = VIRTIO_DEVICE_GET_CLASS(vdev);
140     if (k->bad_features != NULL) {
141         return k->bad_features(vdev);
142     } else {
143         return 0;
144     }
145 }
146 
147 /* Get config of the plugged device. */
148 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
149 {
150     VirtIODevice *vdev = virtio_bus_get_device(bus);
151     VirtioDeviceClass *k;
152 
153     assert(vdev != NULL);
154     k = VIRTIO_DEVICE_GET_CLASS(vdev);
155     if (k->get_config != NULL) {
156         k->get_config(vdev, config);
157     }
158 }
159 
160 /* Set config of the plugged device. */
161 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
162 {
163     VirtIODevice *vdev = virtio_bus_get_device(bus);
164     VirtioDeviceClass *k;
165 
166     assert(vdev != NULL);
167     k = VIRTIO_DEVICE_GET_CLASS(vdev);
168     if (k->set_config != NULL) {
169         k->set_config(vdev, config);
170     }
171 }
172 
173 /* On success, ioeventfd ownership belongs to the caller.  */
174 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
175 {
176     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
177 
178     /* vhost can be used even if ioeventfd=off in the proxy device,
179      * so do not check k->ioeventfd_enabled.
180      */
181     if (!k->ioeventfd_assign) {
182         return -ENOSYS;
183     }
184 
185     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
186         virtio_bus_stop_ioeventfd(bus);
187         /* Remember that we need to restart ioeventfd
188          * when ioeventfd_grabbed becomes zero.
189          */
190         bus->ioeventfd_started = true;
191     }
192     bus->ioeventfd_grabbed++;
193     return 0;
194 }
195 
196 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
197 {
198     assert(bus->ioeventfd_grabbed != 0);
199     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
200         /* Force virtio_bus_start_ioeventfd to act.  */
201         bus->ioeventfd_started = false;
202         virtio_bus_start_ioeventfd(bus);
203     }
204 }
205 
206 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
207 {
208     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
209     DeviceState *proxy = DEVICE(BUS(bus)->parent);
210     VirtIODevice *vdev = virtio_bus_get_device(bus);
211     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
212     int r;
213 
214     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
215         return -ENOSYS;
216     }
217     if (bus->ioeventfd_started) {
218         return 0;
219     }
220 
221     /* Only set our notifier if we have ownership.  */
222     if (!bus->ioeventfd_grabbed) {
223         r = vdc->start_ioeventfd(vdev);
224         if (r < 0) {
225             error_report("%s: failed. Fallback to userspace (slower).", __func__);
226             return r;
227         }
228     }
229     bus->ioeventfd_started = true;
230     return 0;
231 }
232 
233 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
234 {
235     VirtIODevice *vdev;
236     VirtioDeviceClass *vdc;
237 
238     if (!bus->ioeventfd_started) {
239         return;
240     }
241 
242     /* Only remove our notifier if we have ownership.  */
243     if (!bus->ioeventfd_grabbed) {
244         vdev = virtio_bus_get_device(bus);
245         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
246         vdc->stop_ioeventfd(vdev);
247     }
248     bus->ioeventfd_started = false;
249 }
250 
251 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
252 {
253     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
254     DeviceState *proxy = DEVICE(BUS(bus)->parent);
255 
256     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
257 }
258 
259 static void virtio_bus_cleanup_event_notifier(EventNotifier *notifier)
260 {
261     /* Test and clear notifier after disabling event,
262      * in case poll callback didn't have time to run.
263      */
264     virtio_queue_host_notifier_read(notifier);
265     event_notifier_cleanup(notifier);
266 }
267 
268 /*
269  * This function switches ioeventfd on/off in the device.
270  * The caller must set or clear the handlers for the EventNotifier.
271  */
272 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
273 {
274     VirtIODevice *vdev = virtio_bus_get_device(bus);
275     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
276     DeviceState *proxy = DEVICE(BUS(bus)->parent);
277     VirtQueue *vq = virtio_get_queue(vdev, n);
278     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
279     int r = 0;
280 
281     if (!k->ioeventfd_assign) {
282         return -ENOSYS;
283     }
284 
285     if (assign) {
286         r = event_notifier_init(notifier, 1);
287         if (r < 0) {
288             error_report("%s: unable to init event notifier: %s (%d)",
289                          __func__, strerror(-r), r);
290             return r;
291         }
292         r = k->ioeventfd_assign(proxy, notifier, n, true);
293         if (r < 0) {
294             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
295             virtio_bus_cleanup_event_notifier(notifier);
296         }
297     } else {
298         notifier->cleanup = virtio_bus_cleanup_event_notifier;
299         k->ioeventfd_assign(proxy, notifier, n, false);
300     }
301 
302     return r;
303 }
304 
305 static char *virtio_bus_get_dev_path(DeviceState *dev)
306 {
307     BusState *bus = qdev_get_parent_bus(dev);
308     DeviceState *proxy = DEVICE(bus->parent);
309     return qdev_get_dev_path(proxy);
310 }
311 
312 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
313 {
314     return NULL;
315 }
316 
317 static void virtio_bus_class_init(ObjectClass *klass, void *data)
318 {
319     BusClass *bus_class = BUS_CLASS(klass);
320     bus_class->get_dev_path = virtio_bus_get_dev_path;
321     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
322 }
323 
324 static const TypeInfo virtio_bus_info = {
325     .name = TYPE_VIRTIO_BUS,
326     .parent = TYPE_BUS,
327     .instance_size = sizeof(VirtioBusState),
328     .abstract = true,
329     .class_size = sizeof(VirtioBusClass),
330     .class_init = virtio_bus_class_init
331 };
332 
333 static void virtio_register_types(void)
334 {
335     type_register_static(&virtio_bus_info);
336 }
337 
338 type_init(virtio_register_types)
339