xref: /openbmc/qemu/hw/virtio/vhost-user-gpio.c (revision 95fc5ed4) 
1 /*
2  * Vhost-user GPIO virtio device
3  *
4  * Copyright (c) 2022 Viresh Kumar <viresh.kumar@linaro.org>
5  *
6  * SPDX-License-Identifier: GPL-2.0-or-later
7  */
8 
9 #include "qemu/osdep.h"
10 #include "qapi/error.h"
11 #include "hw/qdev-properties.h"
12 #include "hw/virtio/virtio-bus.h"
13 #include "hw/virtio/vhost-user-gpio.h"
14 #include "qemu/error-report.h"
15 #include "standard-headers/linux/virtio_ids.h"
16 #include "trace.h"
17 
18 #define REALIZE_CONNECTION_RETRIES 3
19 
20 /* Features required from VirtIO */
21 static const int feature_bits[] = {
22     VIRTIO_F_VERSION_1,
23     VIRTIO_F_NOTIFY_ON_EMPTY,
24     VIRTIO_RING_F_INDIRECT_DESC,
25     VIRTIO_RING_F_EVENT_IDX,
26     VIRTIO_GPIO_F_IRQ,
27     VIRTIO_F_RING_RESET,
28     VHOST_INVALID_FEATURE_BIT
29 };
30 
31 static void vu_gpio_get_config(VirtIODevice *vdev, uint8_t *config)
32 {
33     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
34 
35     memcpy(config, &gpio->config, sizeof(gpio->config));
36 }
37 
38 static int vu_gpio_config_notifier(struct vhost_dev *dev)
39 {
40     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev->vdev);
41 
42     memcpy(dev->vdev->config, &gpio->config, sizeof(gpio->config));
43     virtio_notify_config(dev->vdev);
44 
45     return 0;
46 }
47 
48 const VhostDevConfigOps gpio_ops = {
49     .vhost_dev_config_notifier = vu_gpio_config_notifier,
50 };
51 
52 static int vu_gpio_start(VirtIODevice *vdev)
53 {
54     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
55     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
56     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
57     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
58     int ret, i;
59 
60     if (!k->set_guest_notifiers) {
61         error_report("binding does not support guest notifiers");
62         return -ENOSYS;
63     }
64 
65     ret = vhost_dev_enable_notifiers(vhost_dev, vdev);
66     if (ret < 0) {
67         error_report("Error enabling host notifiers: %d", ret);
68         return ret;
69     }
70 
71     ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, true);
72     if (ret < 0) {
73         error_report("Error binding guest notifier: %d", ret);
74         goto err_host_notifiers;
75     }
76 
77     /*
78      * Before we start up we need to ensure we have the final feature
79      * set needed for the vhost configuration. The backend may also
80      * apply backend_features when the feature set is sent.
81      */
82     vhost_ack_features(&gpio->vhost_dev, feature_bits, vdev->guest_features);
83 
84     ret = vhost_dev_start(&gpio->vhost_dev, vdev, false);
85     if (ret < 0) {
86         error_report("Error starting vhost-user-gpio: %d", ret);
87         goto err_guest_notifiers;
88     }
89     gpio->started_vu = true;
90 
91     /*
92      * guest_notifier_mask/pending not used yet, so just unmask
93      * everything here. virtio-pci will do the right thing by
94      * enabling/disabling irqfd.
95      */
96     for (i = 0; i < gpio->vhost_dev.nvqs; i++) {
97         vhost_virtqueue_mask(&gpio->vhost_dev, vdev, i, false);
98     }
99 
100     /*
101      * As we must have VHOST_USER_F_PROTOCOL_FEATURES (because
102      * VHOST_USER_GET_CONFIG requires it) we need to explicitly enable
103      * the vrings.
104      */
105     g_assert(vhost_dev->vhost_ops &&
106              vhost_dev->vhost_ops->vhost_set_vring_enable);
107     ret = vhost_dev->vhost_ops->vhost_set_vring_enable(vhost_dev, true);
108     if (ret == 0) {
109         return 0;
110     }
111 
112     error_report("Failed to start vrings for vhost-user-gpio: %d", ret);
113 
114 err_guest_notifiers:
115     k->set_guest_notifiers(qbus->parent, gpio->vhost_dev.nvqs, false);
116 err_host_notifiers:
117     vhost_dev_disable_notifiers(&gpio->vhost_dev, vdev);
118 
119     return ret;
120 }
121 
122 static void vu_gpio_stop(VirtIODevice *vdev)
123 {
124     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
125     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
126     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
127     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
128     int ret;
129 
130     if (!gpio->started_vu) {
131         return;
132     }
133     gpio->started_vu = false;
134 
135     if (!k->set_guest_notifiers) {
136         return;
137     }
138 
139     vhost_dev_stop(vhost_dev, vdev, false);
140 
141     ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
142     if (ret < 0) {
143         error_report("vhost guest notifier cleanup failed: %d", ret);
144         return;
145     }
146 
147     vhost_dev_disable_notifiers(vhost_dev, vdev);
148 }
149 
150 static void vu_gpio_set_status(VirtIODevice *vdev, uint8_t status)
151 {
152     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
153     bool should_start = virtio_device_should_start(vdev, status);
154 
155     trace_virtio_gpio_set_status(status);
156 
157     if (!gpio->connected) {
158         return;
159     }
160 
161     if (vhost_dev_is_started(&gpio->vhost_dev) == should_start) {
162         return;
163     }
164 
165     if (should_start) {
166         if (vu_gpio_start(vdev)) {
167             qemu_chr_fe_disconnect(&gpio->chardev);
168         }
169     } else {
170         vu_gpio_stop(vdev);
171     }
172 }
173 
174 static uint64_t vu_gpio_get_features(VirtIODevice *vdev, uint64_t features,
175                                      Error **errp)
176 {
177     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
178 
179     return vhost_get_features(&gpio->vhost_dev, feature_bits, features);
180 }
181 
182 static void vu_gpio_handle_output(VirtIODevice *vdev, VirtQueue *vq)
183 {
184     /*
185      * Not normally called; it's the daemon that handles the queue;
186      * however virtio's cleanup path can call this.
187      */
188 }
189 
190 static void vu_gpio_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
191 {
192     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
193 
194     /*
195      * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
196      * as the Marco of configure interrupt's IDX, If this driver does not
197      * support, the function will return
198      */
199 
200     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
201         return;
202     }
203 
204     vhost_virtqueue_mask(&gpio->vhost_dev, vdev, idx, mask);
205 }
206 
207 static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserGPIO *gpio)
208 {
209     virtio_delete_queue(gpio->command_vq);
210     virtio_delete_queue(gpio->interrupt_vq);
211     g_free(gpio->vhost_dev.vqs);
212     gpio->vhost_dev.vqs = NULL;
213     virtio_cleanup(vdev);
214     vhost_user_cleanup(&gpio->vhost_user);
215 }
216 
217 static int vu_gpio_connect(DeviceState *dev, Error **errp)
218 {
219     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
220     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
221     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
222     int ret;
223 
224     if (gpio->connected) {
225         return 0;
226     }
227     gpio->connected = true;
228 
229     vhost_dev_set_config_notifier(vhost_dev, &gpio_ops);
230     gpio->vhost_user.supports_config = true;
231 
232     ret = vhost_dev_init(vhost_dev, &gpio->vhost_user,
233                          VHOST_BACKEND_TYPE_USER, 0, errp);
234     if (ret < 0) {
235         return ret;
236     }
237 
238     /* restore vhost state */
239     if (virtio_device_started(vdev, vdev->status)) {
240         vu_gpio_start(vdev);
241     }
242 
243     return 0;
244 }
245 
246 static void vu_gpio_event(void *opaque, QEMUChrEvent event);
247 
248 static void vu_gpio_disconnect(DeviceState *dev)
249 {
250     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
251     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
252 
253     if (!gpio->connected) {
254         return;
255     }
256     gpio->connected = false;
257 
258     vu_gpio_stop(vdev);
259     vhost_dev_cleanup(&gpio->vhost_dev);
260 
261     /* Re-instate the event handler for new connections */
262     qemu_chr_fe_set_handlers(&gpio->chardev,
263                              NULL, NULL, vu_gpio_event,
264                              NULL, dev, NULL, true);
265 }
266 
267 static void vu_gpio_event(void *opaque, QEMUChrEvent event)
268 {
269     DeviceState *dev = opaque;
270     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
271     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
272     Error *local_err = NULL;
273 
274     switch (event) {
275     case CHR_EVENT_OPENED:
276         if (vu_gpio_connect(dev, &local_err) < 0) {
277             qemu_chr_fe_disconnect(&gpio->chardev);
278             return;
279         }
280         break;
281     case CHR_EVENT_CLOSED:
282         /* defer close until later to avoid circular close */
283         vhost_user_async_close(dev, &gpio->chardev, &gpio->vhost_dev,
284                                vu_gpio_disconnect);
285         break;
286     case CHR_EVENT_BREAK:
287     case CHR_EVENT_MUX_IN:
288     case CHR_EVENT_MUX_OUT:
289         /* Ignore */
290         break;
291     }
292 }
293 
294 static int vu_gpio_realize_connect(VHostUserGPIO *gpio, Error **errp)
295 {
296     VirtIODevice *vdev = &gpio->parent_obj;
297     DeviceState *dev = &vdev->parent_obj;
298     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
299     int ret;
300 
301     ret = qemu_chr_fe_wait_connected(&gpio->chardev, errp);
302     if (ret < 0) {
303         return ret;
304     }
305 
306     /*
307      * vu_gpio_connect() may have already connected (via the event
308      * callback) in which case it will just report success.
309      */
310     ret = vu_gpio_connect(dev, errp);
311     if (ret < 0) {
312         qemu_chr_fe_disconnect(&gpio->chardev);
313         return ret;
314     }
315     g_assert(gpio->connected);
316 
317     ret = vhost_dev_get_config(vhost_dev, (uint8_t *)&gpio->config,
318                                sizeof(gpio->config), errp);
319 
320     if (ret < 0) {
321         error_report("vhost-user-gpio: get config failed");
322 
323         qemu_chr_fe_disconnect(&gpio->chardev);
324         vhost_dev_cleanup(vhost_dev);
325         return ret;
326     }
327 
328     return 0;
329 }
330 
331 static void vu_gpio_device_realize(DeviceState *dev, Error **errp)
332 {
333     ERRP_GUARD();
334 
335     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
336     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
337     int retries, ret;
338 
339     if (!gpio->chardev.chr) {
340         error_setg(errp, "vhost-user-gpio: chardev is mandatory");
341         return;
342     }
343 
344     if (!vhost_user_init(&gpio->vhost_user, &gpio->chardev, errp)) {
345         return;
346     }
347 
348     virtio_init(vdev, VIRTIO_ID_GPIO, sizeof(gpio->config));
349 
350     gpio->vhost_dev.nvqs = 2;
351     gpio->command_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
352     gpio->interrupt_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
353     gpio->vhost_dev.vqs = g_new0(struct vhost_virtqueue, gpio->vhost_dev.nvqs);
354 
355     gpio->connected = false;
356 
357     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, vu_gpio_event, NULL,
358                              dev, NULL, true);
359 
360     retries = REALIZE_CONNECTION_RETRIES;
361     g_assert(!*errp);
362     do {
363         if (*errp) {
364             error_prepend(errp, "Reconnecting after error: ");
365             error_report_err(*errp);
366             *errp = NULL;
367         }
368         ret = vu_gpio_realize_connect(gpio, errp);
369     } while (ret < 0 && retries--);
370 
371     if (ret < 0) {
372         do_vhost_user_cleanup(vdev, gpio);
373     }
374 
375     return;
376 }
377 
378 static void vu_gpio_device_unrealize(DeviceState *dev)
379 {
380     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
381     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
382 
383     vu_gpio_set_status(vdev, 0);
384     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, NULL, NULL, NULL, NULL,
385                              false);
386     vhost_dev_cleanup(&gpio->vhost_dev);
387     do_vhost_user_cleanup(vdev, gpio);
388 }
389 
390 static const VMStateDescription vu_gpio_vmstate = {
391     .name = "vhost-user-gpio",
392     .unmigratable = 1,
393 };
394 
395 static Property vu_gpio_properties[] = {
396     DEFINE_PROP_CHR("chardev", VHostUserGPIO, chardev),
397     DEFINE_PROP_END_OF_LIST(),
398 };
399 
400 static void vu_gpio_class_init(ObjectClass *klass, void *data)
401 {
402     DeviceClass *dc = DEVICE_CLASS(klass);
403     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
404 
405     device_class_set_props(dc, vu_gpio_properties);
406     dc->vmsd = &vu_gpio_vmstate;
407     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
408     vdc->realize = vu_gpio_device_realize;
409     vdc->unrealize = vu_gpio_device_unrealize;
410     vdc->get_features = vu_gpio_get_features;
411     vdc->get_config = vu_gpio_get_config;
412     vdc->set_status = vu_gpio_set_status;
413     vdc->guest_notifier_mask = vu_gpio_guest_notifier_mask;
414 }
415 
416 static const TypeInfo vu_gpio_info = {
417     .name = TYPE_VHOST_USER_GPIO,
418     .parent = TYPE_VIRTIO_DEVICE,
419     .instance_size = sizeof(VHostUserGPIO),
420     .class_init = vu_gpio_class_init,
421 };
422 
423 static void vu_gpio_register_types(void)
424 {
425     type_register_static(&vu_gpio_info);
426 }
427 
428 type_init(vu_gpio_register_types)
429