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 macro 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 struct vhost_dev *vu_gpio_get_vhost(VirtIODevice *vdev)
 209 {
 210     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 211     return &gpio->vhost_dev;
 212 }
 213
 214 static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserGPIO *gpio)
 215 {
 216     virtio_delete_queue(gpio->command_vq);
 217     virtio_delete_queue(gpio->interrupt_vq);
 218     g_free(gpio->vhost_vqs);
 219     virtio_cleanup(vdev);
 220     vhost_user_cleanup(&gpio->vhost_user);
 221 }
 222
 223 static int vu_gpio_connect(DeviceState *dev, Error **errp)
 224 {
 225     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 226     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 227     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
 228     int ret;
 229
 230     if (gpio->connected) {
 231         return 0;
 232     }
 233     gpio->connected = true;
 234
 235     vhost_dev_set_config_notifier(vhost_dev, &gpio_ops);
 236     gpio->vhost_user.supports_config = true;
 237
 238     gpio->vhost_dev.nvqs = VHOST_NVQS;
 239     gpio->vhost_dev.vqs = gpio->vhost_vqs;
 240
 241     ret = vhost_dev_init(vhost_dev, &gpio->vhost_user,
 242                          VHOST_BACKEND_TYPE_USER, 0, errp);
 243     if (ret < 0) {
 244         return ret;
 245     }
 246
 247     /* restore vhost state */
 248     if (virtio_device_started(vdev, vdev->status)) {
 249         vu_gpio_start(vdev);
 250     }
 251
 252     return 0;
 253 }
 254
 255 static void vu_gpio_event(void *opaque, QEMUChrEvent event);
 256
 257 static void vu_gpio_disconnect(DeviceState *dev)
 258 {
 259     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 260     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 261
 262     if (!gpio->connected) {
 263         return;
 264     }
 265     gpio->connected = false;
 266
 267     vu_gpio_stop(vdev);
 268     vhost_dev_cleanup(&gpio->vhost_dev);
 269
 270     /* Re-instate the event handler for new connections */
 271     qemu_chr_fe_set_handlers(&gpio->chardev,
 272                              NULL, NULL, vu_gpio_event,
 273                              NULL, dev, NULL, true);
 274 }
 275
 276 static void vu_gpio_event(void *opaque, QEMUChrEvent event)
 277 {
 278     DeviceState *dev = opaque;
 279     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 280     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 281     Error *local_err = NULL;
 282
 283     switch (event) {
 284     case CHR_EVENT_OPENED:
 285         if (vu_gpio_connect(dev, &local_err) < 0) {
 286             qemu_chr_fe_disconnect(&gpio->chardev);
 287             return;
 288         }
 289         break;
 290     case CHR_EVENT_CLOSED:
 291         /* defer close until later to avoid circular close */
 292         vhost_user_async_close(dev, &gpio->chardev, &gpio->vhost_dev,
 293                                vu_gpio_disconnect);
 294         break;
 295     case CHR_EVENT_BREAK:
 296     case CHR_EVENT_MUX_IN:
 297     case CHR_EVENT_MUX_OUT:
 298         /* Ignore */
 299         break;
 300     }
 301 }
 302
 303 static int vu_gpio_realize_connect(VHostUserGPIO *gpio, Error **errp)
 304 {
 305     VirtIODevice *vdev = &gpio->parent_obj;
 306     DeviceState *dev = &vdev->parent_obj;
 307     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
 308     int ret;
 309
 310     ret = qemu_chr_fe_wait_connected(&gpio->chardev, errp);
 311     if (ret < 0) {
 312         return ret;
 313     }
 314
 315     /*
 316      * vu_gpio_connect() may have already connected (via the event
 317      * callback) in which case it will just report success.
 318      */
 319     ret = vu_gpio_connect(dev, errp);
 320     if (ret < 0) {
 321         qemu_chr_fe_disconnect(&gpio->chardev);
 322         return ret;
 323     }
 324     g_assert(gpio->connected);
 325
 326     ret = vhost_dev_get_config(vhost_dev, (uint8_t *)&gpio->config,
 327                                sizeof(gpio->config), errp);
 328
 329     if (ret < 0) {
 330         error_report("vhost-user-gpio: get config failed");
 331
 332         qemu_chr_fe_disconnect(&gpio->chardev);
 333         vhost_dev_cleanup(vhost_dev);
 334         return ret;
 335     }
 336
 337     return 0;
 338 }
 339
 340 static void vu_gpio_device_realize(DeviceState *dev, Error **errp)
 341 {
 342     ERRP_GUARD();
 343
 344     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 345     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
 346     int retries, ret;
 347
 348     if (!gpio->chardev.chr) {
 349         error_setg(errp, "vhost-user-gpio: chardev is mandatory");
 350         return;
 351     }
 352
 353     if (!vhost_user_init(&gpio->vhost_user, &gpio->chardev, errp)) {
 354         return;
 355     }
 356
 357     virtio_init(vdev, VIRTIO_ID_GPIO, sizeof(gpio->config));
 358
 359     gpio->command_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
 360     gpio->interrupt_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
 361     gpio->vhost_vqs = g_new0(struct vhost_virtqueue, VHOST_NVQS);
 362
 363     gpio->connected = false;
 364
 365     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, vu_gpio_event, NULL,
 366                              dev, NULL, true);
 367
 368     retries = REALIZE_CONNECTION_RETRIES;
 369     g_assert(!*errp);
 370     do {
 371         if (*errp) {
 372             error_prepend(errp, "Reconnecting after error: ");
 373             error_report_err(*errp);
 374             *errp = NULL;
 375         }
 376         ret = vu_gpio_realize_connect(gpio, errp);
 377     } while (ret < 0 && retries--);
 378
 379     if (ret < 0) {
 380         do_vhost_user_cleanup(vdev, gpio);
 381     }
 382
 383     return;
 384 }
 385
 386 static void vu_gpio_device_unrealize(DeviceState *dev)
 387 {
 388     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 389     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
 390
 391     vu_gpio_set_status(vdev, 0);
 392     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, NULL, NULL, NULL, NULL,
 393                              false);
 394     vhost_dev_cleanup(&gpio->vhost_dev);
 395     do_vhost_user_cleanup(vdev, gpio);
 396 }
 397
 398 static const VMStateDescription vu_gpio_vmstate = {
 399     .name = "vhost-user-gpio",
 400     .unmigratable = 1,
 401 };
 402
 403 static Property vu_gpio_properties[] = {
 404     DEFINE_PROP_CHR("chardev", VHostUserGPIO, chardev),
 405     DEFINE_PROP_END_OF_LIST(),
 406 };
 407
 408 static void vu_gpio_class_init(ObjectClass *klass, void *data)
 409 {
 410     DeviceClass *dc = DEVICE_CLASS(klass);
 411     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 412
 413     device_class_set_props(dc, vu_gpio_properties);
 414     dc->vmsd = &vu_gpio_vmstate;
 415     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 416     vdc->realize = vu_gpio_device_realize;
 417     vdc->unrealize = vu_gpio_device_unrealize;
 418     vdc->get_features = vu_gpio_get_features;
 419     vdc->get_config = vu_gpio_get_config;
 420     vdc->set_status = vu_gpio_set_status;
 421     vdc->guest_notifier_mask = vu_gpio_guest_notifier_mask;
 422     vdc->get_vhost = vu_gpio_get_vhost;
 423 }
 424
 425 static const TypeInfo vu_gpio_info = {
 426     .name = TYPE_VHOST_USER_GPIO,
 427     .parent = TYPE_VIRTIO_DEVICE,
 428     .instance_size = sizeof(VHostUserGPIO),
 429     .class_init = vu_gpio_class_init,
 430 };
 431
 432 static void vu_gpio_register_types(void)
 433 {
 434     type_register_static(&vu_gpio_info);
 435 }
 436
 437 type_init(vu_gpio_register_types)