hw/virtio/vhost-user-gpio.c

   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)