hw/virtio/virtio-bus.c - qemu - Git at Google

 /*
  * VirtioBus
  *
  *  Copyright (C) 2012 : GreenSocs Ltd
  *      http://www.greensocs.com/ , email: info@greensocs.com
  *
  *  Developed by :
  *  Frederic Konrad   <fred.konrad@greensocs.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License along
  * with this program; if not, see <http://www.gnu.org/licenses/>.
  *
  */

 #include "qemu/osdep.h"
 #include "hw/hw.h"
 #include "qemu/error-report.h"
 #include "hw/qdev.h"
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio.h"

 /* #define DEBUG_VIRTIO_BUS */

 #ifdef DEBUG_VIRTIO_BUS
 #define DPRINTF(fmt, ...) \
 do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
 #else
 #define DPRINTF(fmt, ...) do { } while (0)
 #endif

 /* A VirtIODevice is being plugged */
 void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
 {
     DeviceState *qdev = DEVICE(vdev);
     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
     VirtioBusState *bus = VIRTIO_BUS(qbus);
     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);

     DPRINTF("%s: plug device.\n", qbus->name);

     if (klass->pre_plugged != NULL) {
         klass->pre_plugged(qbus->parent, errp);
     }

     /* Get the features of the plugged device. */
     assert(vdc->get_features != NULL);
     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
                                             errp);

     if (klass->device_plugged != NULL) {
         klass->device_plugged(qbus->parent, errp);
     }
 }

 /* Reset the virtio_bus */
 void virtio_bus_reset(VirtioBusState *bus)
 {
     VirtIODevice *vdev = virtio_bus_get_device(bus);

     DPRINTF("%s: reset device.\n", BUS(bus)->name);
     if (vdev != NULL) {
         virtio_reset(vdev);
     }
 }

 /* A VirtIODevice is being unplugged */
 void virtio_bus_device_unplugged(VirtIODevice *vdev)
 {
     DeviceState *qdev = DEVICE(vdev);
     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);

     DPRINTF("%s: remove device.\n", qbus->name);

     if (vdev != NULL) {
         if (klass->device_unplugged != NULL) {
             klass->device_unplugged(qbus->parent);
         }
     }
 }

 /* Get the device id of the plugged device. */
 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
 {
     VirtIODevice *vdev = virtio_bus_get_device(bus);
     assert(vdev != NULL);
     return vdev->device_id;
 }

 /* Get the config_len field of the plugged device. */
 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
 {
     VirtIODevice *vdev = virtio_bus_get_device(bus);
     assert(vdev != NULL);
     return vdev->config_len;
 }

 /* Get bad features of the plugged device. */
 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
 {
     VirtIODevice *vdev = virtio_bus_get_device(bus);
     VirtioDeviceClass *k;

     assert(vdev != NULL);
     k = VIRTIO_DEVICE_GET_CLASS(vdev);
     if (k->bad_features != NULL) {
         return k->bad_features(vdev);
     } else {
         return 0;
     }
 }

 /* Get config of the plugged device. */
 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
 {
     VirtIODevice *vdev = virtio_bus_get_device(bus);
     VirtioDeviceClass *k;

     assert(vdev != NULL);
     k = VIRTIO_DEVICE_GET_CLASS(vdev);
     if (k->get_config != NULL) {
         k->get_config(vdev, config);
     }
 }

 /* Set config of the plugged device. */
 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
 {
     VirtIODevice *vdev = virtio_bus_get_device(bus);
     VirtioDeviceClass *k;

     assert(vdev != NULL);
     k = VIRTIO_DEVICE_GET_CLASS(vdev);
     if (k->set_config != NULL) {
         k->set_config(vdev, config);
     }
 }

 /*
  * This function handles both assigning the ioeventfd handler and
  * registering it with the kernel.
  * assign: register/deregister ioeventfd with the kernel
  * set_handler: use the generic ioeventfd handler
  */
 static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus,
                                       int n, bool assign, bool set_handler)
 {
     VirtIODevice *vdev = virtio_bus_get_device(bus);
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
     VirtQueue *vq = virtio_get_queue(vdev, n);
     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
     int r = 0;

     if (assign) {
         r = event_notifier_init(notifier, 1);
         if (r < 0) {
             error_report("%s: unable to init event notifier: %s (%d)",
                          __func__, strerror(-r), r);
             return r;
         }
         virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
         r = k->ioeventfd_assign(proxy, notifier, n, assign);
         if (r < 0) {
             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
             virtio_queue_set_host_notifier_fd_handler(vq, false, false);
             event_notifier_cleanup(notifier);
             return r;
         }
     } else {
         k->ioeventfd_assign(proxy, notifier, n, assign);
         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
         event_notifier_cleanup(notifier);
     }
     return r;
 }

 void virtio_bus_start_ioeventfd(VirtioBusState *bus)
 {
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
     DeviceState *proxy = DEVICE(BUS(bus)->parent);
     VirtIODevice *vdev;
     int n, r;

     if (!k->ioeventfd_started || k->ioeventfd_started(proxy)) {
         return;
     }
     if (k->ioeventfd_disabled(proxy)) {
         return;
     }
     vdev = virtio_bus_get_device(bus);
     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
         if (!virtio_queue_get_num(vdev, n)) {
             continue;
         }
         r = set_host_notifier_internal(proxy, bus, n, true, true);
         if (r < 0) {
             goto assign_error;
         }
     }
     k->ioeventfd_set_started(proxy, true, false);
     return;

 assign_error:
     while (--n >= 0) {
         if (!virtio_queue_get_num(vdev, n)) {
             continue;
         }

         r = set_host_notifier_internal(proxy, bus, n, false, false);
         assert(r >= 0);
     }
     k->ioeventfd_set_started(proxy, false, true);
     error_report("%s: failed. Fallback to userspace (slower).", __func__);
 }

 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
 {
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
     DeviceState *proxy = DEVICE(BUS(bus)->parent);
     VirtIODevice *vdev;
     int n, r;

     if (!k->ioeventfd_started || !k->ioeventfd_started(proxy)) {
         return;
     }
     vdev = virtio_bus_get_device(bus);
     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
         if (!virtio_queue_get_num(vdev, n)) {
             continue;
         }
         r = set_host_notifier_internal(proxy, bus, n, false, false);
         assert(r >= 0);
     }
     k->ioeventfd_set_started(proxy, false, false);
 }

 /*
  * This function switches from/to the generic ioeventfd handler.
  * assign==false means 'use generic ioeventfd handler'.
  */
 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
 {
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
     DeviceState *proxy = DEVICE(BUS(bus)->parent);

     if (!k->ioeventfd_started) {
         return -ENOSYS;
     }
     k->ioeventfd_set_disabled(proxy, assign);
     if (assign) {
         /*
          * Stop using the generic ioeventfd, we are doing eventfd handling
          * ourselves below
          *
          * FIXME: We should just switch the handler and not deassign the
          * ioeventfd.
          * Otherwise, there's a window where we don't have an
          * ioeventfd and we may end up with a notification where
          * we don't expect one.
          */
         virtio_bus_stop_ioeventfd(bus);
     }
     return set_host_notifier_internal(proxy, bus, n, assign, false);
 }

 static char *virtio_bus_get_dev_path(DeviceState *dev)
 {
     BusState *bus = qdev_get_parent_bus(dev);
     DeviceState *proxy = DEVICE(bus->parent);
     return qdev_get_dev_path(proxy);
 }

 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
 {
     return NULL;
 }

 static void virtio_bus_class_init(ObjectClass *klass, void *data)
 {
     BusClass *bus_class = BUS_CLASS(klass);
     bus_class->get_dev_path = virtio_bus_get_dev_path;
     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
 }

 static const TypeInfo virtio_bus_info = {
     .name = TYPE_VIRTIO_BUS,
     .parent = TYPE_BUS,
     .instance_size = sizeof(VirtioBusState),
     .abstract = true,
     .class_size = sizeof(VirtioBusClass),
     .class_init = virtio_bus_class_init
 };

 static void virtio_register_types(void)
 {
     type_register_static(&virtio_bus_info);
 }

 type_init(virtio_register_types)
	/*
	* VirtioBus
	*
	* Copyright (C) 2012 : GreenSocs Ltd
	* http://www.greensocs.com/ , email: info@greensocs.com
	*
	* Developed by :
	* Frederic Konrad <fred.konrad@greensocs.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, see <http://www.gnu.org/licenses/>.
	*
	*/

	#include "qemu/osdep.h"
	#include "hw/hw.h"
	#include "qemu/error-report.h"
	#include "hw/qdev.h"
	#include "hw/virtio/virtio-bus.h"
	#include "hw/virtio/virtio.h"

	/* #define DEBUG_VIRTIO_BUS */

	#ifdef DEBUG_VIRTIO_BUS
	#define DPRINTF(fmt, ...) \
	do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
	#else
	#define DPRINTF(fmt, ...) do { } while (0)
	#endif

	/* A VirtIODevice is being plugged */
	void virtio_bus_device_plugged(VirtIODevice vdev, Error *errp)
	{
	DeviceState *qdev = DEVICE(vdev);
	BusState *qbus = BUS(qdev_get_parent_bus(qdev));
	VirtioBusState *bus = VIRTIO_BUS(qbus);
	VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
	VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);

	DPRINTF("%s: plug device.\n", qbus->name);

	if (klass->pre_plugged != NULL) {
	klass->pre_plugged(qbus->parent, errp);
	}

	/* Get the features of the plugged device. */
	assert(vdc->get_features != NULL);
	vdev->host_features = vdc->get_features(vdev, vdev->host_features,
	errp);

	if (klass->device_plugged != NULL) {
	klass->device_plugged(qbus->parent, errp);
	}
	}

	/* Reset the virtio_bus */
	void virtio_bus_reset(VirtioBusState *bus)
	{
	VirtIODevice *vdev = virtio_bus_get_device(bus);

	DPRINTF("%s: reset device.\n", BUS(bus)->name);
	if (vdev != NULL) {
	virtio_reset(vdev);
	}
	}

	/* A VirtIODevice is being unplugged */
	void virtio_bus_device_unplugged(VirtIODevice *vdev)
	{
	DeviceState *qdev = DEVICE(vdev);
	BusState *qbus = BUS(qdev_get_parent_bus(qdev));
	VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);

	DPRINTF("%s: remove device.\n", qbus->name);

	if (vdev != NULL) {
	if (klass->device_unplugged != NULL) {
	klass->device_unplugged(qbus->parent);
	}
	}
	}

	/* Get the device id of the plugged device. */
	uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
	{
	VirtIODevice *vdev = virtio_bus_get_device(bus);
	assert(vdev != NULL);
	return vdev->device_id;
	}

	/* Get the config_len field of the plugged device. */
	size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
	{
	VirtIODevice *vdev = virtio_bus_get_device(bus);
	assert(vdev != NULL);
	return vdev->config_len;
	}

	/* Get bad features of the plugged device. */
	uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
	{
	VirtIODevice *vdev = virtio_bus_get_device(bus);
	VirtioDeviceClass *k;

	assert(vdev != NULL);
	k = VIRTIO_DEVICE_GET_CLASS(vdev);
	if (k->bad_features != NULL) {
	return k->bad_features(vdev);
	} else {
	return 0;
	}
	}

	/* Get config of the plugged device. */
	void virtio_bus_get_vdev_config(VirtioBusState bus, uint8_t config)
	{
	VirtIODevice *vdev = virtio_bus_get_device(bus);
	VirtioDeviceClass *k;

	assert(vdev != NULL);
	k = VIRTIO_DEVICE_GET_CLASS(vdev);
	if (k->get_config != NULL) {
	k->get_config(vdev, config);
	}
	}

	/* Set config of the plugged device. */
	void virtio_bus_set_vdev_config(VirtioBusState bus, uint8_t config)
	{
	VirtIODevice *vdev = virtio_bus_get_device(bus);
	VirtioDeviceClass *k;

	assert(vdev != NULL);
	k = VIRTIO_DEVICE_GET_CLASS(vdev);
	if (k->set_config != NULL) {
	k->set_config(vdev, config);
	}
	}

	/*
	* This function handles both assigning the ioeventfd handler and
	* registering it with the kernel.
	* assign: register/deregister ioeventfd with the kernel
	* set_handler: use the generic ioeventfd handler
	*/
	static int set_host_notifier_internal(DeviceState proxy, VirtioBusState bus,
	int n, bool assign, bool set_handler)
	{
	VirtIODevice *vdev = virtio_bus_get_device(bus);
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
	VirtQueue *vq = virtio_get_queue(vdev, n);
	EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
	int r = 0;

	if (assign) {
	r = event_notifier_init(notifier, 1);
	if (r < 0) {
	error_report("%s: unable to init event notifier: %s (%d)",
	__func__, strerror(-r), r);
	return r;
	}
	virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
	r = k->ioeventfd_assign(proxy, notifier, n, assign);
	if (r < 0) {
	error_report("%s: unable to assign ioeventfd: %d", __func__, r);
	virtio_queue_set_host_notifier_fd_handler(vq, false, false);
	event_notifier_cleanup(notifier);
	return r;
	}
	} else {
	k->ioeventfd_assign(proxy, notifier, n, assign);
	virtio_queue_set_host_notifier_fd_handler(vq, false, false);
	event_notifier_cleanup(notifier);
	}
	return r;
	}

	void virtio_bus_start_ioeventfd(VirtioBusState *bus)
	{
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
	DeviceState *proxy = DEVICE(BUS(bus)->parent);
	VirtIODevice *vdev;
	int n, r;

	if (!k->ioeventfd_started \|\| k->ioeventfd_started(proxy)) {
	return;
	}
	if (k->ioeventfd_disabled(proxy)) {
	return;
	}
	vdev = virtio_bus_get_device(bus);
	for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
	if (!virtio_queue_get_num(vdev, n)) {
	continue;
	}
	r = set_host_notifier_internal(proxy, bus, n, true, true);
	if (r < 0) {
	goto assign_error;
	}
	}
	k->ioeventfd_set_started(proxy, true, false);
	return;

	assign_error:
	while (--n >= 0) {
	if (!virtio_queue_get_num(vdev, n)) {
	continue;
	}

	r = set_host_notifier_internal(proxy, bus, n, false, false);
	assert(r >= 0);
	}
	k->ioeventfd_set_started(proxy, false, true);
	error_report("%s: failed. Fallback to userspace (slower).", __func__);
	}

	void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
	{
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
	DeviceState *proxy = DEVICE(BUS(bus)->parent);
	VirtIODevice *vdev;
	int n, r;

	if (!k->ioeventfd_started \|\| !k->ioeventfd_started(proxy)) {
	return;
	}
	vdev = virtio_bus_get_device(bus);
	for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
	if (!virtio_queue_get_num(vdev, n)) {
	continue;
	}
	r = set_host_notifier_internal(proxy, bus, n, false, false);
	assert(r >= 0);
	}
	k->ioeventfd_set_started(proxy, false, false);
	}

	/*
	* This function switches from/to the generic ioeventfd handler.
	* assign==false means 'use generic ioeventfd handler'.
	*/
	int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
	{
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
	DeviceState *proxy = DEVICE(BUS(bus)->parent);

	if (!k->ioeventfd_started) {
	return -ENOSYS;
	}
	k->ioeventfd_set_disabled(proxy, assign);
	if (assign) {
	/*
	* Stop using the generic ioeventfd, we are doing eventfd handling
	* ourselves below
	*
	* FIXME: We should just switch the handler and not deassign the
	* ioeventfd.
	* Otherwise, there's a window where we don't have an
	* ioeventfd and we may end up with a notification where
	* we don't expect one.
	*/
	virtio_bus_stop_ioeventfd(bus);
	}
	return set_host_notifier_internal(proxy, bus, n, assign, false);
	}

	static char virtio_bus_get_dev_path(DeviceState dev)
	{
	BusState *bus = qdev_get_parent_bus(dev);
	DeviceState *proxy = DEVICE(bus->parent);
	return qdev_get_dev_path(proxy);
	}

	static char virtio_bus_get_fw_dev_path(DeviceState dev)
	{
	return NULL;
	}

	static void virtio_bus_class_init(ObjectClass klass, void data)
	{
	BusClass *bus_class = BUS_CLASS(klass);
	bus_class->get_dev_path = virtio_bus_get_dev_path;
	bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
	}

	static const TypeInfo virtio_bus_info = {
	.name = TYPE_VIRTIO_BUS,
	.parent = TYPE_BUS,
	.instance_size = sizeof(VirtioBusState),
	.abstract = true,
	.class_size = sizeof(VirtioBusClass),
	.class_init = virtio_bus_class_init
	};

	static void virtio_register_types(void)
	{
	type_register_static(&virtio_bus_info);
	}

	type_init(virtio_register_types)