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

 /*
  * Vhost-user filesystem virtio device
  *
  * Copyright 2018-2019 Red Hat, Inc.
  *
  * Authors:
  *  Stefan Hajnoczi <stefanha@redhat.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2 or
  * (at your option) any later version.  See the COPYING file in the
  * top-level directory.
  */

 #include "qemu/osdep.h"
 #include <sys/ioctl.h>
 #include "standard-headers/linux/virtio_fs.h"
 #include "qapi/error.h"
 #include "hw/qdev-properties.h"
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio-access.h"
 #include "qemu/error-report.h"
 #include "hw/virtio/vhost-user-fs.h"
 #include "monitor/monitor.h"

 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
 {
     VHostUserFS *fs = VHOST_USER_FS(vdev);
     struct virtio_fs_config fscfg = {};

     memcpy((char *)fscfg.tag, fs->conf.tag,
            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));

     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);

     memcpy(config, &fscfg, sizeof(fscfg));
 }

 static void vuf_start(VirtIODevice *vdev)
 {
     VHostUserFS *fs = VHOST_USER_FS(vdev);
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     int ret;
     int i;

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

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

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

     fs->vhost_dev.acked_features = vdev->guest_features;
     ret = vhost_dev_start(&fs->vhost_dev, vdev);
     if (ret < 0) {
         error_report("Error starting vhost: %d", -ret);
         goto err_guest_notifiers;
     }

     /*
      * 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 < fs->vhost_dev.nvqs; i++) {
         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
     }

     return;

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

 static void vuf_stop(VirtIODevice *vdev)
 {
     VHostUserFS *fs = VHOST_USER_FS(vdev);
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     int ret;

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

     vhost_dev_stop(&fs->vhost_dev, vdev);

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

     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 }

 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserFS *fs = VHOST_USER_FS(vdev);
     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;

     if (!vdev->vm_running) {
         should_start = false;
     }

     if (fs->vhost_dev.started == should_start) {
         return;
     }

     if (should_start) {
         vuf_start(vdev);
     } else {
         vuf_stop(vdev);
     }
 }

 static uint64_t vuf_get_features(VirtIODevice *vdev,
                                       uint64_t requested_features,
                                       Error **errp)
 {
     /* No feature bits used yet */
     return requested_features;
 }

 static void vuf_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 vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
                                             bool mask)
 {
     VHostUserFS *fs = VHOST_USER_FS(vdev);

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

 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 {
     VHostUserFS *fs = VHOST_USER_FS(vdev);

     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 }

 static void vuf_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserFS *fs = VHOST_USER_FS(dev);
     unsigned int i;
     size_t len;
     int ret;

     if (!fs->conf.chardev.chr) {
         error_setg(errp, "missing chardev");
         return;
     }

     if (!fs->conf.tag) {
         error_setg(errp, "missing tag property");
         return;
     }
     len = strlen(fs->conf.tag);
     if (len == 0) {
         error_setg(errp, "tag property cannot be empty");
         return;
     }
     if (len > sizeof_field(struct virtio_fs_config, tag)) {
         error_setg(errp, "tag property must be %zu bytes or less",
                    sizeof_field(struct virtio_fs_config, tag));
         return;
     }

     if (fs->conf.num_request_queues == 0) {
         error_setg(errp, "num-request-queues property must be larger than 0");
         return;
     }

     if (!is_power_of_2(fs->conf.queue_size)) {
         error_setg(errp, "queue-size property must be a power of 2");
         return;
     }

     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
         error_setg(errp, "queue-size property must be %u or smaller",
                    VIRTQUEUE_MAX_SIZE);
         return;
     }

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

     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
                 sizeof(struct virtio_fs_config));

     /* Hiprio queue */
     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);

     /* Request queues */
     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
     for (i = 0; i < fs->conf.num_request_queues; i++) {
         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
     }

     /* 1 high prio queue, plus the number configured */
     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
                          VHOST_BACKEND_TYPE_USER, 0);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "vhost_dev_init failed");
         goto err_virtio;
     }

     return;

 err_virtio:
     vhost_user_cleanup(&fs->vhost_user);
     virtio_delete_queue(fs->hiprio_vq);
     for (i = 0; i < fs->conf.num_request_queues; i++) {
         virtio_delete_queue(fs->req_vqs[i]);
     }
     g_free(fs->req_vqs);
     virtio_cleanup(vdev);
     g_free(fs->vhost_dev.vqs);
     return;
 }

 static void vuf_device_unrealize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
     VHostUserFS *fs = VHOST_USER_FS(dev);
     int i;

     /* This will stop vhost backend if appropriate. */
     vuf_set_status(vdev, 0);

     vhost_dev_cleanup(&fs->vhost_dev);

     vhost_user_cleanup(&fs->vhost_user);

     virtio_delete_queue(fs->hiprio_vq);
     for (i = 0; i < fs->conf.num_request_queues; i++) {
         virtio_delete_queue(fs->req_vqs[i]);
     }
     g_free(fs->req_vqs);
     virtio_cleanup(vdev);
     g_free(fs->vhost_dev.vqs);
     fs->vhost_dev.vqs = NULL;
 }

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

 static Property vuf_properties[] = {
     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
                        conf.num_request_queues, 1),
     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
     DEFINE_PROP_END_OF_LIST(),
 };

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

     device_class_set_props(dc, vuf_properties);
     dc->vmsd = &vuf_vmstate;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
     vdc->realize = vuf_device_realize;
     vdc->unrealize = vuf_device_unrealize;
     vdc->get_features = vuf_get_features;
     vdc->get_config = vuf_get_config;
     vdc->set_status = vuf_set_status;
     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 }

 static const TypeInfo vuf_info = {
     .name = TYPE_VHOST_USER_FS,
     .parent = TYPE_VIRTIO_DEVICE,
     .instance_size = sizeof(VHostUserFS),
     .class_init = vuf_class_init,
 };

 static void vuf_register_types(void)
 {
     type_register_static(&vuf_info);
 }

 type_init(vuf_register_types)
	/*
	* Vhost-user filesystem virtio device
	*
	* Copyright 2018-2019 Red Hat, Inc.
	*
	* Authors:
	* Stefan Hajnoczi <stefanha@redhat.com>
	*
	* This work is licensed under the terms of the GNU GPL, version 2 or
	* (at your option) any later version. See the COPYING file in the
	* top-level directory.
	*/

	#include "qemu/osdep.h"
	#include <sys/ioctl.h>
	#include "standard-headers/linux/virtio_fs.h"
	#include "qapi/error.h"
	#include "hw/qdev-properties.h"
	#include "hw/virtio/virtio-bus.h"
	#include "hw/virtio/virtio-access.h"
	#include "qemu/error-report.h"
	#include "hw/virtio/vhost-user-fs.h"
	#include "monitor/monitor.h"

	static void vuf_get_config(VirtIODevice vdev, uint8_t config)
	{
	VHostUserFS *fs = VHOST_USER_FS(vdev);
	struct virtio_fs_config fscfg = {};

	memcpy((char *)fscfg.tag, fs->conf.tag,
	MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));

	virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);

	memcpy(config, &fscfg, sizeof(fscfg));
	}

	static void vuf_start(VirtIODevice *vdev)
	{
	VHostUserFS *fs = VHOST_USER_FS(vdev);
	BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
	int ret;
	int i;

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

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

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

	fs->vhost_dev.acked_features = vdev->guest_features;
	ret = vhost_dev_start(&fs->vhost_dev, vdev);
	if (ret < 0) {
	error_report("Error starting vhost: %d", -ret);
	goto err_guest_notifiers;
	}

	/*
	* 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 < fs->vhost_dev.nvqs; i++) {
	vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
	}

	return;

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

	static void vuf_stop(VirtIODevice *vdev)
	{
	VHostUserFS *fs = VHOST_USER_FS(vdev);
	BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
	VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
	int ret;

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

	vhost_dev_stop(&fs->vhost_dev, vdev);

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

	vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
	}

	static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
	{
	VHostUserFS *fs = VHOST_USER_FS(vdev);
	bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;

	if (!vdev->vm_running) {
	should_start = false;
	}

	if (fs->vhost_dev.started == should_start) {
	return;
	}

	if (should_start) {
	vuf_start(vdev);
	} else {
	vuf_stop(vdev);
	}
	}

	static uint64_t vuf_get_features(VirtIODevice *vdev,
	uint64_t requested_features,
	Error **errp)
	{
	/* No feature bits used yet */
	return requested_features;
	}

	static void vuf_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 vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
	bool mask)
	{
	VHostUserFS *fs = VHOST_USER_FS(vdev);

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

	static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
	{
	VHostUserFS *fs = VHOST_USER_FS(vdev);

	return vhost_virtqueue_pending(&fs->vhost_dev, idx);
	}

	static void vuf_device_realize(DeviceState dev, Error *errp)
	{
	VirtIODevice *vdev = VIRTIO_DEVICE(dev);
	VHostUserFS *fs = VHOST_USER_FS(dev);
	unsigned int i;
	size_t len;
	int ret;

	if (!fs->conf.chardev.chr) {
	error_setg(errp, "missing chardev");
	return;
	}

	if (!fs->conf.tag) {
	error_setg(errp, "missing tag property");
	return;
	}
	len = strlen(fs->conf.tag);
	if (len == 0) {
	error_setg(errp, "tag property cannot be empty");
	return;
	}
	if (len > sizeof_field(struct virtio_fs_config, tag)) {
	error_setg(errp, "tag property must be %zu bytes or less",
	sizeof_field(struct virtio_fs_config, tag));
	return;
	}

	if (fs->conf.num_request_queues == 0) {
	error_setg(errp, "num-request-queues property must be larger than 0");
	return;
	}

	if (!is_power_of_2(fs->conf.queue_size)) {
	error_setg(errp, "queue-size property must be a power of 2");
	return;
	}

	if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
	error_setg(errp, "queue-size property must be %u or smaller",
	VIRTQUEUE_MAX_SIZE);
	return;
	}

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

	virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
	sizeof(struct virtio_fs_config));

	/* Hiprio queue */
	fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);

	/* Request queues */
	fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
	for (i = 0; i < fs->conf.num_request_queues; i++) {
	fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
	}

	/* 1 high prio queue, plus the number configured */
	fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
	fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
	ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
	VHOST_BACKEND_TYPE_USER, 0);
	if (ret < 0) {
	error_setg_errno(errp, -ret, "vhost_dev_init failed");
	goto err_virtio;
	}

	return;

	err_virtio:
	vhost_user_cleanup(&fs->vhost_user);
	virtio_delete_queue(fs->hiprio_vq);
	for (i = 0; i < fs->conf.num_request_queues; i++) {
	virtio_delete_queue(fs->req_vqs[i]);
	}
	g_free(fs->req_vqs);
	virtio_cleanup(vdev);
	g_free(fs->vhost_dev.vqs);
	return;
	}

	static void vuf_device_unrealize(DeviceState dev, Error *errp)
	{
	VirtIODevice *vdev = VIRTIO_DEVICE(dev);
	VHostUserFS *fs = VHOST_USER_FS(dev);
	int i;

	/* This will stop vhost backend if appropriate. */
	vuf_set_status(vdev, 0);

	vhost_dev_cleanup(&fs->vhost_dev);

	vhost_user_cleanup(&fs->vhost_user);

	virtio_delete_queue(fs->hiprio_vq);
	for (i = 0; i < fs->conf.num_request_queues; i++) {
	virtio_delete_queue(fs->req_vqs[i]);
	}
	g_free(fs->req_vqs);
	virtio_cleanup(vdev);
	g_free(fs->vhost_dev.vqs);
	fs->vhost_dev.vqs = NULL;
	}

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

	static Property vuf_properties[] = {
	DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
	DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
	DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
	conf.num_request_queues, 1),
	DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
	DEFINE_PROP_END_OF_LIST(),
	};

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

	device_class_set_props(dc, vuf_properties);
	dc->vmsd = &vuf_vmstate;
	set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
	vdc->realize = vuf_device_realize;
	vdc->unrealize = vuf_device_unrealize;
	vdc->get_features = vuf_get_features;
	vdc->get_config = vuf_get_config;
	vdc->set_status = vuf_set_status;
	vdc->guest_notifier_mask = vuf_guest_notifier_mask;
	vdc->guest_notifier_pending = vuf_guest_notifier_pending;
	}

	static const TypeInfo vuf_info = {
	.name = TYPE_VHOST_USER_FS,
	.parent = TYPE_VIRTIO_DEVICE,
	.instance_size = sizeof(VHostUserFS),
	.class_init = vuf_class_init,
	};

	static void vuf_register_types(void)
	{
	type_register_static(&vuf_info);
	}

	type_init(vuf_register_types)