hw/virtio/vhost-user-gpio.c - qemu - Git at Google

 /*
  * Vhost-user GPIO virtio device
  *
  * Copyright (c) 2022 Viresh Kumar <viresh.kumar@linaro.org>
  *
  * SPDX-License-Identifier: GPL-2.0-or-later
  */

 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "hw/qdev-properties.h"
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/vhost-user-gpio.h"
 #include "qemu/error-report.h"
 #include "standard-headers/linux/virtio_ids.h"
 #include "trace.h"

 #define VHOST_NVQS 2

 /* Features required from VirtIO */
 static const int feature_bits[] = {
     VIRTIO_F_VERSION_1,
     VIRTIO_F_NOTIFY_ON_EMPTY,
     VIRTIO_RING_F_INDIRECT_DESC,
     VIRTIO_RING_F_EVENT_IDX,
     VIRTIO_GPIO_F_IRQ,
     VIRTIO_F_RING_RESET,
     VHOST_INVALID_FEATURE_BIT
 };

 static void vu_gpio_get_config(VirtIODevice *vdev, uint8_t *config)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

     memcpy(config, &gpio->config, sizeof(gpio->config));
 }

 static int vu_gpio_config_notifier(struct vhost_dev *dev)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev->vdev);

     memcpy(dev->vdev->config, &gpio->config, sizeof(gpio->config));
     virtio_notify_config(dev->vdev);

     return 0;
 }

 const VhostDevConfigOps gpio_ops = {
     .vhost_dev_config_notifier = vu_gpio_config_notifier,
 };

 static int vu_gpio_start(VirtIODevice *vdev)
 {
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
     int ret, i;

     if (!k->set_guest_notifiers) {
         error_report("binding does not support guest notifiers");
         return -ENOSYS;
     }

     ret = vhost_dev_enable_notifiers(vhost_dev, vdev);
     if (ret < 0) {
         error_report("Error enabling host notifiers: %d", ret);
         return ret;
     }

     ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, true);
     if (ret < 0) {
         error_report("Error binding guest notifier: %d", ret);
         goto err_host_notifiers;
     }

     /*
      * Before we start up we need to ensure we have the final feature
      * set needed for the vhost configuration. The backend may also
      * apply backend_features when the feature set is sent.
      */
     vhost_ack_features(&gpio->vhost_dev, feature_bits, vdev->guest_features);

     ret = vhost_dev_start(&gpio->vhost_dev, vdev, false);
     if (ret < 0) {
         error_report("Error starting vhost-user-gpio: %d", ret);
         goto err_guest_notifiers;
     }
     gpio->started_vu = true;

     /*
      * guest_notifier_mask/pending not used yet, so just unmask
      * everything here. virtio-pci will do the right thing by
      * enabling/disabling irqfd.
      */
     for (i = 0; i < gpio->vhost_dev.nvqs; i++) {
         vhost_virtqueue_mask(&gpio->vhost_dev, vdev, i, false);
     }

     /*
      * As we must have VHOST_USER_F_PROTOCOL_FEATURES (because
      * VHOST_USER_GET_CONFIG requires it) we need to explicitly enable
      * the vrings.
      */
     g_assert(vhost_dev->vhost_ops &&
              vhost_dev->vhost_ops->vhost_set_vring_enable);
     ret = vhost_dev->vhost_ops->vhost_set_vring_enable(vhost_dev, true);
     if (ret == 0) {
         return 0;
     }

     error_report("Failed to start vrings for vhost-user-gpio: %d", ret);

 err_guest_notifiers:
     k->set_guest_notifiers(qbus->parent, gpio->vhost_dev.nvqs, false);
 err_host_notifiers:
     vhost_dev_disable_notifiers(&gpio->vhost_dev, vdev);

     return ret;
 }

 static void vu_gpio_stop(VirtIODevice *vdev)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
     int ret;

     if (!gpio->started_vu) {
         return;
     }
     gpio->started_vu = false;

     if (!k->set_guest_notifiers) {
         return;
     }

     vhost_dev_stop(vhost_dev, vdev, false);

     ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
     if (ret < 0) {
         error_report("vhost guest notifier cleanup failed: %d", ret);
         return;
     }

     vhost_dev_disable_notifiers(vhost_dev, vdev);
 }

 static void vu_gpio_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
     bool should_start = virtio_device_should_start(vdev, status);

     trace_virtio_gpio_set_status(status);

     if (!gpio->connected) {
         return;
     }

     if (vhost_dev_is_started(&gpio->vhost_dev) == should_start) {
         return;
     }

     if (should_start) {
         if (vu_gpio_start(vdev)) {
             qemu_chr_fe_disconnect(&gpio->chardev);
         }
     } else {
         vu_gpio_stop(vdev);
     }
 }

 static uint64_t vu_gpio_get_features(VirtIODevice *vdev, uint64_t features,
                                      Error **errp)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

     return vhost_get_features(&gpio->vhost_dev, feature_bits, features);
 }

 static void vu_gpio_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 {
     /*
      * Not normally called; it's the daemon that handles the queue;
      * however virtio's cleanup path can call this.
      */
 }

 static void vu_gpio_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

     /*
      * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
      * as the macro of configure interrupt's IDX, If this driver does not
      * support, the function will return
      */

     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
         return;
     }

     vhost_virtqueue_mask(&gpio->vhost_dev, vdev, idx, mask);
 }

 static struct vhost_dev *vu_gpio_get_vhost(VirtIODevice *vdev)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
     return &gpio->vhost_dev;
 }

 static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserGPIO *gpio)
 {
     virtio_delete_queue(gpio->command_vq);
     virtio_delete_queue(gpio->interrupt_vq);
     g_free(gpio->vhost_vqs);
     virtio_cleanup(vdev);
     vhost_user_cleanup(&gpio->vhost_user);
 }

 static int vu_gpio_connect(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
     int ret;

     if (gpio->connected) {
         return 0;
     }
     gpio->connected = true;

     vhost_dev_set_config_notifier(vhost_dev, &gpio_ops);
     gpio->vhost_user.supports_config = true;

     gpio->vhost_dev.nvqs = VHOST_NVQS;
     gpio->vhost_dev.vqs = gpio->vhost_vqs;

     ret = vhost_dev_init(vhost_dev, &gpio->vhost_user,
                          VHOST_BACKEND_TYPE_USER, 0, errp);
     if (ret < 0) {
         return ret;
     }

     /* restore vhost state */
     if (virtio_device_started(vdev, vdev->status)) {
         vu_gpio_start(vdev);
     }

     return 0;
 }

 static void vu_gpio_event(void *opaque, QEMUChrEvent event);

 static void vu_gpio_disconnect(DeviceState *dev)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

     if (!gpio->connected) {
         return;
     }
     gpio->connected = false;

     vu_gpio_stop(vdev);
     vhost_dev_cleanup(&gpio->vhost_dev);

     /* Re-instate the event handler for new connections */
     qemu_chr_fe_set_handlers(&gpio->chardev,
                              NULL, NULL, vu_gpio_event,
                              NULL, dev, NULL, true);
 }

 static void vu_gpio_event(void *opaque, QEMUChrEvent event)
 {
     DeviceState *dev = opaque;
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
     Error *local_err = NULL;

     switch (event) {
     case CHR_EVENT_OPENED:
         if (vu_gpio_connect(dev, &local_err) < 0) {
             qemu_chr_fe_disconnect(&gpio->chardev);
             return;
         }
         break;
     case CHR_EVENT_CLOSED:
         /* defer close until later to avoid circular close */
         vhost_user_async_close(dev, &gpio->chardev, &gpio->vhost_dev,
                                vu_gpio_disconnect, vu_gpio_event);
         break;
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
         /* Ignore */
         break;
     }
 }

 static int vu_gpio_realize_connect(VHostUserGPIO *gpio, Error **errp)
 {
     VirtIODevice *vdev = &gpio->parent_obj;
     DeviceState *dev = &vdev->parent_obj;
     struct vhost_dev *vhost_dev = &gpio->vhost_dev;
     int ret;

     ret = qemu_chr_fe_wait_connected(&gpio->chardev, errp);
     if (ret < 0) {
         return ret;
     }

     /*
      * vu_gpio_connect() may have already connected (via the event
      * callback) in which case it will just report success.
      */
     ret = vu_gpio_connect(dev, errp);
     if (ret < 0) {
         qemu_chr_fe_disconnect(&gpio->chardev);
         return ret;
     }
     g_assert(gpio->connected);

     ret = vhost_dev_get_config(vhost_dev, (uint8_t *)&gpio->config,
                                sizeof(gpio->config), errp);

     if (ret < 0) {
         error_report("vhost-user-gpio: get config failed");

         qemu_chr_fe_disconnect(&gpio->chardev);
         vhost_dev_cleanup(vhost_dev);
         return ret;
     }

     return 0;
 }

 static void vu_gpio_device_realize(DeviceState *dev, Error **errp)
 {
     ERRP_GUARD();

     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
     int retries, ret;

     if (!gpio->chardev.chr) {
         error_setg(errp, "vhost-user-gpio: chardev is mandatory");
         return;
     }

     if (!vhost_user_init(&gpio->vhost_user, &gpio->chardev, errp)) {
         return;
     }

     virtio_init(vdev, VIRTIO_ID_GPIO, sizeof(gpio->config));

     gpio->command_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
     gpio->interrupt_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
     gpio->vhost_vqs = g_new0(struct vhost_virtqueue, VHOST_NVQS);

     gpio->connected = false;

     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, vu_gpio_event, NULL,
                              dev, NULL, true);

     retries = VU_REALIZE_CONN_RETRIES;
     g_assert(!*errp);
     do {
         if (*errp) {
             error_prepend(errp, "Reconnecting after error: ");
             error_report_err(*errp);
             *errp = NULL;
         }
         ret = vu_gpio_realize_connect(gpio, errp);
     } while (ret < 0 && retries--);

     if (ret < 0) {
         do_vhost_user_cleanup(vdev, gpio);
     }

     return;
 }

 static void vu_gpio_device_unrealize(DeviceState *dev)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);

     vu_gpio_set_status(vdev, 0);
     qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, NULL, NULL, NULL, NULL,
                              false);
     vhost_dev_cleanup(&gpio->vhost_dev);
     do_vhost_user_cleanup(vdev, gpio);
 }

 static const VMStateDescription vu_gpio_vmstate = {
     .name = "vhost-user-gpio",
     .unmigratable = 1,
 };

 static Property vu_gpio_properties[] = {
     DEFINE_PROP_CHR("chardev", VHostUserGPIO, chardev),
     DEFINE_PROP_END_OF_LIST(),
 };

 static void vu_gpio_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);

     device_class_set_props(dc, vu_gpio_properties);
     dc->vmsd = &vu_gpio_vmstate;
     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
     vdc->realize = vu_gpio_device_realize;
     vdc->unrealize = vu_gpio_device_unrealize;
     vdc->get_features = vu_gpio_get_features;
     vdc->get_config = vu_gpio_get_config;
     vdc->set_status = vu_gpio_set_status;
     vdc->guest_notifier_mask = vu_gpio_guest_notifier_mask;
     vdc->get_vhost = vu_gpio_get_vhost;
 }

 static const TypeInfo vu_gpio_info = {
     .name = TYPE_VHOST_USER_GPIO,
     .parent = TYPE_VIRTIO_DEVICE,
     .instance_size = sizeof(VHostUserGPIO),
     .class_init = vu_gpio_class_init,
 };

 static void vu_gpio_register_types(void)
 {
     type_register_static(&vu_gpio_info);
 }

 type_init(vu_gpio_register_types)
	/*
	* Vhost-user GPIO virtio device
	*
	* Copyright (c) 2022 Viresh Kumar <viresh.kumar@linaro.org>
	*
	* SPDX-License-Identifier: GPL-2.0-or-later
	*/

	#include "qemu/osdep.h"
	#include "qapi/error.h"
	#include "hw/qdev-properties.h"
	#include "hw/virtio/virtio-bus.h"
	#include "hw/virtio/vhost-user-gpio.h"
	#include "qemu/error-report.h"
	#include "standard-headers/linux/virtio_ids.h"
	#include "trace.h"

	#define VHOST_NVQS 2

	/* Features required from VirtIO */
	static const int feature_bits[] = {
	VIRTIO_F_VERSION_1,
	VIRTIO_F_NOTIFY_ON_EMPTY,
	VIRTIO_RING_F_INDIRECT_DESC,
	VIRTIO_RING_F_EVENT_IDX,
	VIRTIO_GPIO_F_IRQ,
	VIRTIO_F_RING_RESET,
	VHOST_INVALID_FEATURE_BIT
	};

	static void vu_gpio_get_config(VirtIODevice vdev, uint8_t config)
	{
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

	memcpy(config, &gpio->config, sizeof(gpio->config));
	}

	static int vu_gpio_config_notifier(struct vhost_dev *dev)
	{
	VHostUserGPIO *gpio = VHOST_USER_GPIO(dev->vdev);

	memcpy(dev->vdev->config, &gpio->config, sizeof(gpio->config));
	virtio_notify_config(dev->vdev);

	return 0;
	}

	const VhostDevConfigOps gpio_ops = {
	.vhost_dev_config_notifier = vu_gpio_config_notifier,
	};

	static int vu_gpio_start(VirtIODevice *vdev)
	{
	BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
	struct vhost_dev *vhost_dev = &gpio->vhost_dev;
	int ret, i;

	if (!k->set_guest_notifiers) {
	error_report("binding does not support guest notifiers");
	return -ENOSYS;
	}

	ret = vhost_dev_enable_notifiers(vhost_dev, vdev);
	if (ret < 0) {
	error_report("Error enabling host notifiers: %d", ret);
	return ret;
	}

	ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, true);
	if (ret < 0) {
	error_report("Error binding guest notifier: %d", ret);
	goto err_host_notifiers;
	}

	/*
	* Before we start up we need to ensure we have the final feature
	* set needed for the vhost configuration. The backend may also
	* apply backend_features when the feature set is sent.
	*/
	vhost_ack_features(&gpio->vhost_dev, feature_bits, vdev->guest_features);

	ret = vhost_dev_start(&gpio->vhost_dev, vdev, false);
	if (ret < 0) {
	error_report("Error starting vhost-user-gpio: %d", ret);
	goto err_guest_notifiers;
	}
	gpio->started_vu = true;

	/*
	* guest_notifier_mask/pending not used yet, so just unmask
	* everything here. virtio-pci will do the right thing by
	* enabling/disabling irqfd.
	*/
	for (i = 0; i < gpio->vhost_dev.nvqs; i++) {
	vhost_virtqueue_mask(&gpio->vhost_dev, vdev, i, false);
	}

	/*
	* As we must have VHOST_USER_F_PROTOCOL_FEATURES (because
	* VHOST_USER_GET_CONFIG requires it) we need to explicitly enable
	* the vrings.
	*/
	g_assert(vhost_dev->vhost_ops &&
	vhost_dev->vhost_ops->vhost_set_vring_enable);
	ret = vhost_dev->vhost_ops->vhost_set_vring_enable(vhost_dev, true);
	if (ret == 0) {
	return 0;
	}

	error_report("Failed to start vrings for vhost-user-gpio: %d", ret);

	err_guest_notifiers:
	k->set_guest_notifiers(qbus->parent, gpio->vhost_dev.nvqs, false);
	err_host_notifiers:
	vhost_dev_disable_notifiers(&gpio->vhost_dev, vdev);

	return ret;
	}

	static void vu_gpio_stop(VirtIODevice *vdev)
	{
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
	BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
	struct vhost_dev *vhost_dev = &gpio->vhost_dev;
	int ret;

	if (!gpio->started_vu) {
	return;
	}
	gpio->started_vu = false;

	if (!k->set_guest_notifiers) {
	return;
	}

	vhost_dev_stop(vhost_dev, vdev, false);

	ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
	if (ret < 0) {
	error_report("vhost guest notifier cleanup failed: %d", ret);
	return;
	}

	vhost_dev_disable_notifiers(vhost_dev, vdev);
	}

	static void vu_gpio_set_status(VirtIODevice *vdev, uint8_t status)
	{
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
	bool should_start = virtio_device_should_start(vdev, status);

	trace_virtio_gpio_set_status(status);

	if (!gpio->connected) {
	return;
	}

	if (vhost_dev_is_started(&gpio->vhost_dev) == should_start) {
	return;
	}

	if (should_start) {
	if (vu_gpio_start(vdev)) {
	qemu_chr_fe_disconnect(&gpio->chardev);
	}
	} else {
	vu_gpio_stop(vdev);
	}
	}

	static uint64_t vu_gpio_get_features(VirtIODevice *vdev, uint64_t features,
	Error **errp)
	{
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

	return vhost_get_features(&gpio->vhost_dev, feature_bits, features);
	}

	static void vu_gpio_handle_output(VirtIODevice vdev, VirtQueue vq)
	{
	/*
	* Not normally called; it's the daemon that handles the queue;
	* however virtio's cleanup path can call this.
	*/
	}

	static void vu_gpio_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
	{
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

	/*
	* Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
	* as the macro of configure interrupt's IDX, If this driver does not
	* support, the function will return
	*/

	if (idx == VIRTIO_CONFIG_IRQ_IDX) {
	return;
	}

	vhost_virtqueue_mask(&gpio->vhost_dev, vdev, idx, mask);
	}

	static struct vhost_dev vu_gpio_get_vhost(VirtIODevice vdev)
	{
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
	return &gpio->vhost_dev;
	}

	static void do_vhost_user_cleanup(VirtIODevice vdev, VHostUserGPIO gpio)
	{
	virtio_delete_queue(gpio->command_vq);
	virtio_delete_queue(gpio->interrupt_vq);
	g_free(gpio->vhost_vqs);
	virtio_cleanup(vdev);
	vhost_user_cleanup(&gpio->vhost_user);
	}

	static int vu_gpio_connect(DeviceState dev, Error *errp)
	{
	VirtIODevice *vdev = VIRTIO_DEVICE(dev);
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
	struct vhost_dev *vhost_dev = &gpio->vhost_dev;
	int ret;

	if (gpio->connected) {
	return 0;
	}
	gpio->connected = true;

	vhost_dev_set_config_notifier(vhost_dev, &gpio_ops);
	gpio->vhost_user.supports_config = true;

	gpio->vhost_dev.nvqs = VHOST_NVQS;
	gpio->vhost_dev.vqs = gpio->vhost_vqs;

	ret = vhost_dev_init(vhost_dev, &gpio->vhost_user,
	VHOST_BACKEND_TYPE_USER, 0, errp);
	if (ret < 0) {
	return ret;
	}

	/* restore vhost state */
	if (virtio_device_started(vdev, vdev->status)) {
	vu_gpio_start(vdev);
	}

	return 0;
	}

	static void vu_gpio_event(void *opaque, QEMUChrEvent event);

	static void vu_gpio_disconnect(DeviceState *dev)
	{
	VirtIODevice *vdev = VIRTIO_DEVICE(dev);
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);

	if (!gpio->connected) {
	return;
	}
	gpio->connected = false;

	vu_gpio_stop(vdev);
	vhost_dev_cleanup(&gpio->vhost_dev);

	/* Re-instate the event handler for new connections */
	qemu_chr_fe_set_handlers(&gpio->chardev,
	NULL, NULL, vu_gpio_event,
	NULL, dev, NULL, true);
	}

	static void vu_gpio_event(void *opaque, QEMUChrEvent event)
	{
	DeviceState *dev = opaque;
	VirtIODevice *vdev = VIRTIO_DEVICE(dev);
	VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
	Error *local_err = NULL;

	switch (event) {
	case CHR_EVENT_OPENED:
	if (vu_gpio_connect(dev, &local_err) < 0) {
	qemu_chr_fe_disconnect(&gpio->chardev);
	return;
	}
	break;
	case CHR_EVENT_CLOSED:
	/* defer close until later to avoid circular close */
	vhost_user_async_close(dev, &gpio->chardev, &gpio->vhost_dev,
	vu_gpio_disconnect, vu_gpio_event);
	break;
	case CHR_EVENT_BREAK:
	case CHR_EVENT_MUX_IN:
	case CHR_EVENT_MUX_OUT:
	/* Ignore */
	break;
	}
	}

	static int vu_gpio_realize_connect(VHostUserGPIO gpio, Error *errp)
	{
	VirtIODevice *vdev = &gpio->parent_obj;
	DeviceState *dev = &vdev->parent_obj;
	struct vhost_dev *vhost_dev = &gpio->vhost_dev;
	int ret;

	ret = qemu_chr_fe_wait_connected(&gpio->chardev, errp);
	if (ret < 0) {
	return ret;
	}

	/*
	* vu_gpio_connect() may have already connected (via the event
	* callback) in which case it will just report success.
	*/
	ret = vu_gpio_connect(dev, errp);
	if (ret < 0) {
	qemu_chr_fe_disconnect(&gpio->chardev);
	return ret;
	}
	g_assert(gpio->connected);

	ret = vhost_dev_get_config(vhost_dev, (uint8_t *)&gpio->config,
	sizeof(gpio->config), errp);

	if (ret < 0) {
	error_report("vhost-user-gpio: get config failed");

	qemu_chr_fe_disconnect(&gpio->chardev);
	vhost_dev_cleanup(vhost_dev);
	return ret;
	}

	return 0;
	}

	static void vu_gpio_device_realize(DeviceState dev, Error *errp)
	{
	ERRP_GUARD();

	VirtIODevice *vdev = VIRTIO_DEVICE(dev);
	VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);
	int retries, ret;

	if (!gpio->chardev.chr) {
	error_setg(errp, "vhost-user-gpio: chardev is mandatory");
	return;
	}

	if (!vhost_user_init(&gpio->vhost_user, &gpio->chardev, errp)) {
	return;
	}

	virtio_init(vdev, VIRTIO_ID_GPIO, sizeof(gpio->config));

	gpio->command_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
	gpio->interrupt_vq = virtio_add_queue(vdev, 256, vu_gpio_handle_output);
	gpio->vhost_vqs = g_new0(struct vhost_virtqueue, VHOST_NVQS);

	gpio->connected = false;

	qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, vu_gpio_event, NULL,
	dev, NULL, true);

	retries = VU_REALIZE_CONN_RETRIES;
	g_assert(!*errp);
	do {
	if (*errp) {
	error_prepend(errp, "Reconnecting after error: ");
	error_report_err(*errp);
	*errp = NULL;
	}
	ret = vu_gpio_realize_connect(gpio, errp);
	} while (ret < 0 && retries--);

	if (ret < 0) {
	do_vhost_user_cleanup(vdev, gpio);
	}

	return;
	}

	static void vu_gpio_device_unrealize(DeviceState *dev)
	{
	VirtIODevice *vdev = VIRTIO_DEVICE(dev);
	VHostUserGPIO *gpio = VHOST_USER_GPIO(dev);

	vu_gpio_set_status(vdev, 0);
	qemu_chr_fe_set_handlers(&gpio->chardev, NULL, NULL, NULL, NULL, NULL, NULL,
	false);
	vhost_dev_cleanup(&gpio->vhost_dev);
	do_vhost_user_cleanup(vdev, gpio);
	}

	static const VMStateDescription vu_gpio_vmstate = {
	.name = "vhost-user-gpio",
	.unmigratable = 1,
	};

	static Property vu_gpio_properties[] = {
	DEFINE_PROP_CHR("chardev", VHostUserGPIO, chardev),
	DEFINE_PROP_END_OF_LIST(),
	};

	static void vu_gpio_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);
	VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);

	device_class_set_props(dc, vu_gpio_properties);
	dc->vmsd = &vu_gpio_vmstate;
	set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
	vdc->realize = vu_gpio_device_realize;
	vdc->unrealize = vu_gpio_device_unrealize;
	vdc->get_features = vu_gpio_get_features;
	vdc->get_config = vu_gpio_get_config;
	vdc->set_status = vu_gpio_set_status;
	vdc->guest_notifier_mask = vu_gpio_guest_notifier_mask;
	vdc->get_vhost = vu_gpio_get_vhost;
	}

	static const TypeInfo vu_gpio_info = {
	.name = TYPE_VHOST_USER_GPIO,
	.parent = TYPE_VIRTIO_DEVICE,
	.instance_size = sizeof(VHostUserGPIO),
	.class_init = vu_gpio_class_init,
	};

	static void vu_gpio_register_types(void)
	{
	type_register_static(&vu_gpio_info);
	}

	type_init(vu_gpio_register_types)