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);
  85     if (ret < 0) {
  86         error_report("Error starting vhost-user-gpio: %d", ret);
  87         goto err_guest_notifiers;
  88     }
  89
  90     /*
  91      * guest_notifier_mask/pending not used yet, so just unmask
  92      * everything here. virtio-pci will do the right thing by
  93      * enabling/disabling irqfd.
  94      */
  95     for (i = 0; i < gpio->vhost_dev.nvqs; i++) {
  96         vhost_virtqueue_mask(&gpio->vhost_dev, vdev, i, false);
  97     }
  98
  99     /*
 100      * As we must have VHOST_USER_F_PROTOCOL_FEATURES (because
 101      * VHOST_USER_GET_CONFIG requires it) we need to explicitly enable
 102      * the vrings.
 103      */
 104     g_assert(vhost_dev->vhost_ops &&
 105              vhost_dev->vhost_ops->vhost_set_vring_enable);
 106     ret = vhost_dev->vhost_ops->vhost_set_vring_enable(vhost_dev, true);
 107     if (ret == 0) {
 108         return 0;
 109     }
 110
 111     error_report("Failed to start vrings for vhost-user-gpio: %d", ret);
 112
 113 err_guest_notifiers:
 114     k->set_guest_notifiers(qbus->parent, gpio->vhost_dev.nvqs, false);
 115 err_host_notifiers:
 116     vhost_dev_disable_notifiers(&gpio->vhost_dev, vdev);
 117
 118     return ret;
 119 }
 120
 121 static void vu_gpio_stop(VirtIODevice *vdev)
 122 {
 123     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 124     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 125     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 126     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
 127     int ret;
 128
 129     if (!k->set_guest_notifiers) {
 130         return;
 131     }
 132
 133     /*
 134      * We can call vu_gpio_stop multiple times, for example from
 135      * vm_state_notify and the final object finalisation. Check we
 136      * aren't already stopped before doing so.
 137      */
 138     if (!vhost_dev_is_started(vhost_dev)) {
 139         return;
 140     }
 141
 142     vhost_dev_stop(vhost_dev, vdev);
 143
 144     ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
 145     if (ret < 0) {
 146         error_report("vhost guest notifier cleanup failed: %d", ret);
 147         return;
 148     }
 149
 150     vhost_dev_disable_notifiers(vhost_dev, vdev);
 151 }
 152
 153 static void vu_gpio_set_status(VirtIODevice *vdev, uint8_t status)
 154 {
 155     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 156     bool should_start = virtio_device_should_start(vdev, status);
 157
 158     trace_virtio_gpio_set_status(status);
 159
 160     if (!gpio->connected) {
 161         return;
 162     }
 163
 164     if (vhost_dev_is_started(&gpio->vhost_dev) == should_start) {
 165         return;
 166     }
 167
 168     if (should_start) {
 169         if (vu_gpio_start(vdev)) {
 170             qemu_chr_fe_disconnect(&gpio->chardev);
 171         }
 172     } else {
 173         vu_gpio_stop(vdev);
 174     }
 175 }
 176
 177 static uint64_t vu_gpio_get_features(VirtIODevice *vdev, uint64_t features,
 178                                      Error **errp)
 179 {
 180     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 181
 182     return vhost_get_features(&gpio->vhost_dev, feature_bits, features);
 183 }
 184
 185 static void vu_gpio_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 186 {
 187     /*
 188      * Not normally called; it's the daemon that handles the queue;
 189      * however virtio's cleanup path can call this.
 190      */
 191 }
 192
 193 static void vu_gpio_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
 194 {
 195     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 196
 197     vhost_virtqueue_mask(&gpio->vhost_dev, vdev, idx, mask);
 198 }
 199
 200 static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserGPIO *gpio)
 201 {
 202     virtio_delete_queue(gpio->command_vq);
 203     virtio_delete_queue(gpio->interrupt_vq);
 204     g_free(gpio->vhost_dev.vqs);
 205     gpio->vhost_dev.vqs = NULL;
 206     virtio_cleanup(vdev);
 207     vhost_user_cleanup(&gpio->vhost_user);
 208 }
 209
 210 static int vu_gpio_connect(DeviceState *dev, Error **errp)
 211 {
 212     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 213     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 214     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
 215     int ret;
 216
 217     if (gpio->connected) {
 218         return 0;
 219     }
 220     gpio->connected = true;
 221
 222     vhost_dev_set_config_notifier(vhost_dev, &gpio_ops);
 223     gpio->vhost_user.supports_config = true;
 224
 225     ret = vhost_dev_init(vhost_dev, &gpio->vhost_user,
 226                          VHOST_BACKEND_TYPE_USER, 0, errp);
 227     if (ret < 0) {
 228         return ret;
 229     }
 230
 231     /* restore vhost state */
 232     if (virtio_device_started(vdev, vdev->status)) {
 233         vu_gpio_start(vdev);
 234     }
 235
 236     return 0;
 237 }
 238
 239 static void vu_gpio_disconnect(DeviceState *dev)
 240 {
 241     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 242     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 243
 244     if (!gpio->connected) {
 245         return;
 246     }
 247     gpio->connected = false;
 248
 249     vu_gpio_stop(vdev);
 250     vhost_dev_cleanup(&gpio->vhost_dev);
 251 }
 252
 253 static void vu_gpio_event(void *opaque, QEMUChrEvent event)
 254 {
 255     DeviceState *dev = opaque;
 256     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 257     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
 258     Error *local_err = NULL;
 259
 260     switch (event) {
 261     case CHR_EVENT_OPENED:
 262         if (vu_gpio_connect(dev, &local_err) < 0) {
 263             qemu_chr_fe_disconnect(&gpio->chardev);
 264             return;
 265         }
 266         break;
 267     case CHR_EVENT_CLOSED:
 268         vu_gpio_disconnect(dev);
 269         break;
 270     case CHR_EVENT_BREAK:
 271     case CHR_EVENT_MUX_IN:
 272     case CHR_EVENT_MUX_OUT:
 273         /* Ignore */
 274         break;
 275     }
 276 }
 277
 278 static int vu_gpio_realize_connect(VHostUserGPIO *gpio, Error **errp)
 279 {
 280     VirtIODevice *vdev = &gpio->parent_obj;
 281     DeviceState *dev = &vdev->parent_obj;
 282     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
 283     int ret;
 284
 285     ret = qemu_chr_fe_wait_connected(&gpio->chardev, errp);
 286     if (ret < 0) {
 287         return ret;
 288     }
 289
 290     /*
 291      * vu_gpio_connect() may have already connected (via the event
 292      * callback) in which case it will just report success.
 293      */
 294     ret = vu_gpio_connect(dev, errp);
 295     if (ret < 0) {
 296         qemu_chr_fe_disconnect(&gpio->chardev);
 297         return ret;
 298     }
 299     g_assert(gpio->connected);
 300
 301     ret = vhost_dev_get_config(vhost_dev, (uint8_t *)&gpio->config,
 302                                sizeof(gpio->config), errp);
 303
 304     if (ret < 0) {
 305         error_report("vhost-user-gpio: get config failed");
 306
 307         qemu_chr_fe_disconnect(&gpio->chardev);
 308         vhost_dev_cleanup(vhost_dev);
 309         return ret;
 310     }
 311
 312     return 0;
 313 }
 314
 315 static void vu_gpio_device_realize(DeviceState *dev, Error **errp)
 316 {
 317     ERRP_GUARD();
 318
 319     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 320     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
 321     int retries, ret;
 322
 323     if (!gpio->chardev.chr) {
 324         error_setg(errp, "vhost-user-gpio: chardev is mandatory");
 325         return;
 326     }
 327
 328     if (!vhost_user_init(&gpio->vhost_user, &gpio->chardev, errp)) {
 329         return;
 330     }
 331
 332     virtio_init(vdev, VIRTIO_ID_GPIO, sizeof(gpio->config));
 333
 334     gpio->vhost_dev.nvqs = 2;
 335     gpio->command_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
 336     gpio->interrupt_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
 337     gpio->vhost_dev.vqs = g_new0(struct vhost_virtqueue, gpio->vhost_dev.nvqs);
 338
 339     gpio->connected = false;
 340
 341     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, vu_gpio_event, NULL,
 342                              dev, NULL, true);
 343
 344     retries = REALIZE_CONNECTION_RETRIES;
 345     g_assert(!*errp);
 346     do {
 347         if (*errp) {
 348             error_prepend(errp, "Reconnecting after error: ");
 349             error_report_err(*errp);
 350             *errp = NULL;
 351         }
 352         ret = vu_gpio_realize_connect(gpio, errp);
 353     } while (ret < 0 && retries--);
 354
 355     if (ret < 0) {
 356         do_vhost_user_cleanup(vdev, gpio);
 357     }
 358
 359     return;
 360 }
 361
 362 static void vu_gpio_device_unrealize(DeviceState *dev)
 363 {
 364     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 365     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
 366
 367     vu_gpio_set_status(vdev, 0);
 368     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, NULL, NULL, NULL, NULL,
 369                              false);
 370     vhost_dev_cleanup(&gpio->vhost_dev);
 371     do_vhost_user_cleanup(vdev, gpio);
 372 }
 373
 374 static const VMStateDescription vu_gpio_vmstate = {
 375     .name = "vhost-user-gpio",
 376     .unmigratable = 1,
 377 };
 378
 379 static Property vu_gpio_properties[] = {
 380     DEFINE_PROP_CHR("chardev", VHostUserGPIO, chardev),
 381     DEFINE_PROP_END_OF_LIST(),
 382 };
 383
 384 static void vu_gpio_class_init(ObjectClass *klass, void *data)
 385 {
 386     DeviceClass *dc = DEVICE_CLASS(klass);
 387     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 388
 389     device_class_set_props(dc, vu_gpio_properties);
 390     dc->vmsd = &vu_gpio_vmstate;
 391     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 392     vdc->realize = vu_gpio_device_realize;
 393     vdc->unrealize = vu_gpio_device_unrealize;
 394     vdc->get_features = vu_gpio_get_features;
 395     vdc->get_config = vu_gpio_get_config;
 396     vdc->set_status = vu_gpio_set_status;
 397     vdc->guest_notifier_mask = vu_gpio_guest_notifier_mask;
 398 }
 399
 400 static const TypeInfo vu_gpio_info = {
 401     .name = TYPE_VHOST_USER_GPIO,
 402     .parent = TYPE_VIRTIO_DEVICE,
 403     .instance_size = sizeof(VHostUserGPIO),
 404     .class_init = vu_gpio_class_init,
 405 };
 406
 407 static void vu_gpio_register_types(void)
 408 {
 409     type_register_static(&vu_gpio_info);
 410 }
 411
 412 type_init(vu_gpio_register_types)