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