xref: /openbmc/qemu/hw/virtio/virtio-bus.c (revision 4921d0a7) 
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     virtio_bus_stop_ioeventfd(bus);
108     if (vdev != NULL) {
109         virtio_reset(vdev);
110     }
111 }
112 
113 /* A VirtIODevice is being unplugged */
114 void virtio_bus_device_unplugged(VirtIODevice *vdev)
115 {
116     DeviceState *qdev = DEVICE(vdev);
117     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
118     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
119 
120     DPRINTF("%s: remove device.\n", qbus->name);
121 
122     if (vdev != NULL) {
123         if (klass->device_unplugged != NULL) {
124             klass->device_unplugged(qbus->parent);
125         }
126     }
127 }
128 
129 /* Get the device id of the plugged device. */
130 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
131 {
132     VirtIODevice *vdev = virtio_bus_get_device(bus);
133     assert(vdev != NULL);
134     return vdev->device_id;
135 }
136 
137 /* Get the config_len field of the plugged device. */
138 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
139 {
140     VirtIODevice *vdev = virtio_bus_get_device(bus);
141     assert(vdev != NULL);
142     return vdev->config_len;
143 }
144 
145 /* Get bad features of the plugged device. */
146 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
147 {
148     VirtIODevice *vdev = virtio_bus_get_device(bus);
149     VirtioDeviceClass *k;
150 
151     assert(vdev != NULL);
152     k = VIRTIO_DEVICE_GET_CLASS(vdev);
153     if (k->bad_features != NULL) {
154         return k->bad_features(vdev);
155     } else {
156         return 0;
157     }
158 }
159 
160 /* Get config of the plugged device. */
161 void virtio_bus_get_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->get_config != NULL) {
169         k->get_config(vdev, config);
170     }
171 }
172 
173 /* Set config of the plugged device. */
174 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
175 {
176     VirtIODevice *vdev = virtio_bus_get_device(bus);
177     VirtioDeviceClass *k;
178 
179     assert(vdev != NULL);
180     k = VIRTIO_DEVICE_GET_CLASS(vdev);
181     if (k->set_config != NULL) {
182         k->set_config(vdev, config);
183     }
184 }
185 
186 /* On success, ioeventfd ownership belongs to the caller.  */
187 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
188 {
189     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
190 
191     /* vhost can be used even if ioeventfd=off in the proxy device,
192      * so do not check k->ioeventfd_enabled.
193      */
194     if (!k->ioeventfd_assign) {
195         return -ENOSYS;
196     }
197 
198     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
199         virtio_bus_stop_ioeventfd(bus);
200         /* Remember that we need to restart ioeventfd
201          * when ioeventfd_grabbed becomes zero.
202          */
203         bus->ioeventfd_started = true;
204     }
205     bus->ioeventfd_grabbed++;
206     return 0;
207 }
208 
209 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
210 {
211     assert(bus->ioeventfd_grabbed != 0);
212     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
213         /* Force virtio_bus_start_ioeventfd to act.  */
214         bus->ioeventfd_started = false;
215         virtio_bus_start_ioeventfd(bus);
216     }
217 }
218 
219 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
220 {
221     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
222     DeviceState *proxy = DEVICE(BUS(bus)->parent);
223     VirtIODevice *vdev = virtio_bus_get_device(bus);
224     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
225     int r;
226 
227     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
228         return -ENOSYS;
229     }
230     if (bus->ioeventfd_started) {
231         return 0;
232     }
233 
234     /* Only set our notifier if we have ownership.  */
235     if (!bus->ioeventfd_grabbed) {
236         r = vdc->start_ioeventfd(vdev);
237         if (r < 0) {
238             error_report("%s: failed. Fallback to userspace (slower).", __func__);
239             return r;
240         }
241     }
242     bus->ioeventfd_started = true;
243     return 0;
244 }
245 
246 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
247 {
248     VirtIODevice *vdev;
249     VirtioDeviceClass *vdc;
250 
251     if (!bus->ioeventfd_started) {
252         return;
253     }
254 
255     /* Only remove our notifier if we have ownership.  */
256     if (!bus->ioeventfd_grabbed) {
257         vdev = virtio_bus_get_device(bus);
258         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
259         vdc->stop_ioeventfd(vdev);
260     }
261     bus->ioeventfd_started = false;
262 }
263 
264 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
265 {
266     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
267     DeviceState *proxy = DEVICE(BUS(bus)->parent);
268 
269     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
270 }
271 
272 /*
273  * This function switches ioeventfd on/off in the device.
274  * The caller must set or clear the handlers for the EventNotifier.
275  */
276 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
277 {
278     VirtIODevice *vdev = virtio_bus_get_device(bus);
279     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
280     DeviceState *proxy = DEVICE(BUS(bus)->parent);
281     VirtQueue *vq = virtio_get_queue(vdev, n);
282     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
283     int r = 0;
284 
285     if (!k->ioeventfd_assign) {
286         return -ENOSYS;
287     }
288 
289     if (assign) {
290         r = event_notifier_init(notifier, 1);
291         if (r < 0) {
292             error_report("%s: unable to init event notifier: %s (%d)",
293                          __func__, strerror(-r), r);
294             return r;
295         }
296         r = k->ioeventfd_assign(proxy, notifier, n, true);
297         if (r < 0) {
298             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
299             virtio_bus_cleanup_host_notifier(bus, n);
300         }
301     } else {
302         k->ioeventfd_assign(proxy, notifier, n, false);
303     }
304 
305     if (r == 0) {
306         virtio_queue_set_host_notifier_enabled(vq, assign);
307     }
308 
309     return r;
310 }
311 
312 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
313 {
314     VirtIODevice *vdev = virtio_bus_get_device(bus);
315     VirtQueue *vq = virtio_get_queue(vdev, n);
316     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
317 
318     /* Test and clear notifier after disabling event,
319      * in case poll callback didn't have time to run.
320      */
321     virtio_queue_host_notifier_read(notifier);
322     event_notifier_cleanup(notifier);
323 }
324 
325 static char *virtio_bus_get_dev_path(DeviceState *dev)
326 {
327     BusState *bus = qdev_get_parent_bus(dev);
328     DeviceState *proxy = DEVICE(bus->parent);
329     return qdev_get_dev_path(proxy);
330 }
331 
332 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
333 {
334     return NULL;
335 }
336 
337 bool virtio_bus_device_iommu_enabled(VirtIODevice *vdev)
338 {
339     DeviceState *qdev = DEVICE(vdev);
340     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
341     VirtioBusState *bus = VIRTIO_BUS(qbus);
342     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
343 
344     if (!klass->iommu_enabled) {
345         return false;
346     }
347 
348     return klass->iommu_enabled(qbus->parent);
349 }
350 
351 static void virtio_bus_class_init(ObjectClass *klass, void *data)
352 {
353     BusClass *bus_class = BUS_CLASS(klass);
354     bus_class->get_dev_path = virtio_bus_get_dev_path;
355     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
356 }
357 
358 static const TypeInfo virtio_bus_info = {
359     .name = TYPE_VIRTIO_BUS,
360     .parent = TYPE_BUS,
361     .instance_size = sizeof(VirtioBusState),
362     .abstract = true,
363     .class_size = sizeof(VirtioBusClass),
364     .class_init = virtio_bus_class_init
365 };
366 
367 static void virtio_register_types(void)
368 {
369     type_register_static(&virtio_bus_info);
370 }
371 
372 type_init(virtio_register_types)
373