/*
* VDUSE (vDPA Device in Userspace) library
*
* Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights reserved.
*
* Author:
* Xie Yongji <xieyongji@bytedance.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#ifndef LIBVDUSE_H
#define LIBVDUSE_H
#include <stdint.h>
#include <sys/uio.h>
#define VIRTQUEUE_MAX_SIZE 1024
/* VDUSE device structure */
typedef struct VduseDev VduseDev;
/* Virtqueue structure */
typedef struct VduseVirtq VduseVirtq;
/* Some operation of VDUSE backend */
typedef struct VduseOps {
/* Called when virtqueue can be processed */
void (*enable_queue)(VduseDev *dev, VduseVirtq *vq);
/* Called when virtqueue processing should be stopped */
void (*disable_queue)(VduseDev *dev, VduseVirtq *vq);
} VduseOps;
/* Describing elements of the I/O buffer */
typedef struct VduseVirtqElement {
/* Descriptor table index */
unsigned int index;
/* Number of physically-contiguous device-readable descriptors */
unsigned int out_num;
/* Number of physically-contiguous device-writable descriptors */
unsigned int in_num;
/* Array to store physically-contiguous device-writable descriptors */
struct iovec *in_sg;
/* Array to store physically-contiguous device-readable descriptors */
struct iovec *out_sg;
} VduseVirtqElement;
/**
* vduse_get_virtio_features:
*
* Get supported virtio features
*
* Returns: supported feature bits
*/
uint64_t vduse_get_virtio_features(void);
/**
* vduse_queue_get_dev:
* @vq: specified virtqueue
*
* Get corresponding VDUSE device from the virtqueue.
*
* Returns: a pointer to VDUSE device on success, NULL on failure.
*/
VduseDev *vduse_queue_get_dev(VduseVirtq *vq);
/**
* vduse_queue_get_fd:
* @vq: specified virtqueue
*
* Get the kick fd for the virtqueue.
*
* Returns: file descriptor on success, -1 on failure.
*/
int vduse_queue_get_fd(VduseVirtq *vq);
/**
* vduse_queue_pop:
* @vq: specified virtqueue
* @sz: the size of struct to return (must be >= VduseVirtqElement)
*
* Pop an element from virtqueue available ring.
*
* Returns: a pointer to a structure containing VduseVirtqElement on success,
* NULL on failure.
*/
void *vduse_queue_pop(VduseVirtq *vq, size_t sz);
/**
* vduse_queue_push:
* @vq: specified virtqueue
* @elem: pointer to VduseVirtqElement returned by vduse_queue_pop()
* @len: length in bytes to write
*
* Push an element to virtqueue used ring.
*/
void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
unsigned int len);
/**
* vduse_queue_notify:
* @vq: specified virtqueue
*
* Request to notify the queue.
*/
void vduse_queue_notify(VduseVirtq *vq);
/**
* vduse_dev_get_priv:
* @dev: VDUSE device
*
* Get the private pointer passed to vduse_dev_create().
*
* Returns: private pointer on success, NULL on failure.
*/
void *vduse_dev_get_priv(VduseDev *dev);
/**
* vduse_dev_get_queue:
* @dev: VDUSE device
* @index: virtqueue index
*
* Get the specified virtqueue.
*
* Returns: a pointer to the virtqueue on success, NULL on failure.
*/
VduseVirtq *vduse_dev_get_queue(VduseDev *dev, int index);
/**
* vduse_dev_get_fd:
* @dev: VDUSE device
*
* Get the control message fd for the VDUSE device.
*
* Returns: file descriptor on success, -1 on failure.
*/
int vduse_dev_get_fd(VduseDev *dev);
/**
* vduse_dev_handler:
* @dev: VDUSE device
*
* Used to process the control message.
*
* Returns: file descriptor on success, -errno on failure.
*/
int vduse_dev_handler(VduseDev *dev);
/**
* vduse_dev_update_config:
* @dev: VDUSE device
* @size: the size to write to configuration space
* @offset: the offset from the beginning of configuration space
* @buffer: the buffer used to write from
*
* Update device configuration space and inject a config interrupt.
*
* Returns: 0 on success, -errno on failure.
*/
int vduse_dev_update_config(VduseDev *dev, uint32_t size,
uint32_t offset, char *buffer);
/**
* vduse_dev_setup_queue:
* @dev: VDUSE device
* @index: virtqueue index
* @max_size: the max size of virtqueue
*
* Setup the specified virtqueue.
*
* Returns: 0 on success, -errno on failure.
*/
int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size);
/**
* vduse_set_reconnect_log_file:
* @dev: VDUSE device
* @file: filename of reconnect log
*
* Specify the file to store log for reconnecting. It should
* be called before vduse_dev_setup_queue().
*
* Returns: 0 on success, -errno on failure.
*/
int vduse_set_reconnect_log_file(VduseDev *dev, const char *filename);
/**
* vduse_dev_create_by_fd:
* @fd: passed file descriptor
* @num_queues: the number of virtqueues
* @ops: the operation of VDUSE backend
* @priv: private pointer
*
* Create VDUSE device from a passed file descriptor.
*
* Returns: pointer to VDUSE device on success, NULL on failure.
*/
VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
const VduseOps *ops, void *priv);
/**
* vduse_dev_create_by_name:
* @name: VDUSE device name
* @num_queues: the number of virtqueues
* @ops: the operation of VDUSE backend
* @priv: private pointer
*
* Create VDUSE device on /dev/vduse/$NAME.
*
* Returns: pointer to VDUSE device on success, NULL on failure.
*/
VduseDev *vduse_dev_create_by_name(const char *name, uint16_t num_queues,
const VduseOps *ops, void *priv);
/**
* vduse_dev_create:
* @name: VDUSE device name
* @device_id: virtio device id
* @vendor_id: virtio vendor id
* @features: virtio features
* @num_queues: the number of virtqueues
* @config_size: the size of the configuration space
* @config: the buffer of the configuration space
* @ops: the operation of VDUSE backend
* @priv: private pointer
*
* Create VDUSE device.
*
* Returns: pointer to VDUSE device on success, NULL on failure.
*/
VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
uint32_t vendor_id, uint64_t features,
uint16_t num_queues, uint32_t config_size,
char *config, const VduseOps *ops, void *priv);
/**
* vduse_dev_destroy:
* @dev: VDUSE device
*
* Destroy the VDUSE device.
*
* Returns: 0 on success, -errno on failure.
*/
int vduse_dev_destroy(VduseDev *dev);
#endif
