[RFC,v1,1/2] vfio_user: Add library for vfio over socket

diff --git a/lib/librte_vfio_user/rte_vfio_user.h b/lib/librte_vfio_user/rte_vfio_user.h
new file mode 100644
index 000000000..d36516084
--- /dev/null
+++ b/lib/librte_vfio_user/rte_vfio_user.h
@@ -0,0 +1,335 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2020 Intel Corporation
+ */
+
+#ifndef _VFIO_USER_H
+#define _VFIO_USER_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <linux/vfio.h>
+#include <net/if.h>
+#include <sys/queue.h>
+#include <sys/un.h>
+
+#define VFIO_USER_MSG_MAX_NREGIONS 8
+#define VFIO_USER_MAX_MEM_REGIONS 256
+#define VFIO_MAX_RW_DATA 256
+#define VFIO_USER_MAX_FD 64
+#define VFIO_USER_IRQ_MAX_DATA 64
+#define VFIO_USER_MAX_IRQ_FD 64
+
+typedef enum VFIO_USER_CMD_TYPE {
+	VFIO_USER_NONE = 0,
+	VFIO_USER_VERSION = 1,
+	VFIO_USER_DMA_MAP = 2,
+	VFIO_USER_DMA_UNMAP = 3,
+	VFIO_USER_DEVICE_GET_INFO = 4,
+	VFIO_USER_DEVICE_GET_REGION_INFO = 5,
+	VFIO_USER_DEVICE_GET_IRQ_INFO = 6,
+	VFIO_USER_DEVICE_SET_IRQS = 7,
+	VFIO_USER_REGION_READ = 8,
+	VFIO_USER_REGION_WRITE = 9,
+	VFIO_USER_DMA_READ = 10,
+	VFIO_USER_DMA_WRITE = 11,
+	VFIO_USER_VM_INTERRUPT = 12,
+	VFIO_USER_DEVICE_RESET = 13,
+	VFIO_USER_MAX = 14,
+} VFIO_USER_CMD_TYPE;
+
+struct vfio_user_mem_reg {
+	uint64_t gpa;
+	uint64_t size;
+	uint64_t fd_offset;
+	uint32_t protection;	/* attributes in <sys/mman.h> */
+#define VFIO_USER_MEM_MAPPABLE	(0x1 << 0)
+	uint32_t flags;
+};
+
+struct vfio_user_dev_info {
+	uint32_t argsz;		/* Reserved in vfio-user */
+	uint32_t flags;
+	uint32_t num_regions;
+	uint32_t num_irqs;
+};
+
+struct vfio_user_reg_rw {
+	uint64_t reg_offset;
+	uint32_t reg_idx;
+	uint32_t size;
+	char data[VFIO_MAX_RW_DATA];
+};
+
+struct vfio_user_dma_rw {
+	uint64_t addr;
+	uint32_t size;
+	char data[VFIO_MAX_RW_DATA];
+};
+
+struct vfio_user_intr {
+	uint32_t type;
+	uint32_t vector;
+};
+
+typedef struct vfio_user_msg {
+	uint16_t dev_id;
+	uint16_t msg_id;
+	uint32_t cmd;
+	uint32_t size;
+#define VFIO_USER_REPLY_MASK	(0x1 << 0)
+#define VFIO_USER_NEED_NO_RP	(0x1 << 1)
+	uint32_t flags;
+	union {
+		struct vfio_user_mem_reg memory[VFIO_USER_MSG_MAX_NREGIONS];
+		struct vfio_user_dev_info dev_info;
+		struct vfio_region_info reg_info;
+		struct vfio_irq_info irq_info;
+		struct vfio_irq_set irq_set;
+		struct vfio_user_reg_rw reg_rw;
+		struct vfio_user_dma_rw dma_rw;
+		struct vfio_user_intr intr;
+	} payload;
+	int fds[VFIO_USER_MAX_FD];
+	int fd_num;
+} __attribute((packed)) VFIO_USER_MSG;
+
+#define VFIO_USER_MSG_HDR_SIZE offsetof(VFIO_USER_MSG, payload.dev_info)
+
+enum vfio_user_msg_handle_result {
+	VFIO_USER_MSG_HANDLE_ERR = -1,
+	VFIO_USER_MSG_HANDLE_OK = 0,
+	VFIO_USER_MSG_HANDLE_REPLY = 1,
+};
+
+struct vfio_user_mem_table_entry {
+	struct vfio_user_mem_reg region;
+	uint64_t host_user_addr;
+	void	 *mmap_addr;
+	uint64_t mmap_size;
+	int fd;
+};
+
+struct vfio_user_mem {
+	uint32_t entry_num;
+	struct vfio_user_mem_table_entry entry[VFIO_USER_MAX_MEM_REGIONS];
+};
+
+struct vfio_user_regions {
+	uint32_t reg_num;
+	struct vfio_region_info **reg_info;
+};
+
+struct vfio_user_irq_info {
+	uint32_t irq_num;
+	struct vfio_irq_info *irq_info;
+};
+
+struct vfio_user_irq_set {
+	uint32_t set_num;
+	struct vfio_irq_set **irq;
+	int fds[VFIO_USER_MAX_IRQ_FD];
+};
+
+struct vfio_user_irqs {
+	struct vfio_user_irq_info *info;
+	struct vfio_user_irq_set *set;
+};
+
+struct vfio_user_region_resource {
+	void *base;
+	uint32_t size;
+	int fd;
+};
+
+struct vfio_user_resource {
+	uint16_t resource_num;
+	struct vfio_user_region_resource res[];
+};
+
+struct vfio_user {
+	int dev_id;
+	int is_ready;
+#define IF_NAME_SZ (IFNAMSIZ > PATH_MAX ? IFNAMSIZ : PATH_MAX)
+	char sock_addr[IF_NAME_SZ];
+	const struct vfio_user_notify_ops *ops;
+	struct vfio_user_mem *mem;
+	struct vfio_user_dev_info *dev_info;
+	struct vfio_user_regions *reg;
+	struct vfio_user_irqs *irq;
+	struct vfio_user_resource *res;
+};
+
+struct vfio_user_notify_ops {
+	int (*new_device)(int dev_id);		/* Add device */
+	void (*destroy_device)(int dev_id);	/* Remove device */
+	int (*update_status)(int dev_id);	/* Update device status */
+};
+
+typedef void (*vfio_user_log)(const char *format, ...);
+
+typedef int (*event_handler)(int fd, void *data);
+
+typedef struct listen_fd_info {
+	int fd;
+	uint32_t event;
+	event_handler ev_handle;
+	void *data;
+} FD_INFO;
+
+struct vfio_user_epoll {
+	int epfd;
+	FD_INFO fdinfo[VFIO_USER_MAX_FD];
+	uint32_t fd_num;	/* Current num of listen_fd */
+	struct epoll_event *events;
+	pthread_mutex_t fd_mutex;
+};
+
+struct vfio_user_socket {
+	char *sock_addr;
+	struct sockaddr_un un;
+	int sock_fd;
+	int dev_id;
+};
+
+struct vfio_user_ep_sock {
+	struct vfio_user_epoll ep;
+	struct vfio_user_socket *sock[VFIO_USER_MAX_FD];
+	uint32_t sock_num;
+	pthread_mutex_t mutex;
+};
+
+/**
+ * Register a vfio-user device.
+ *
+ * @param sock_addr
+ *  Unix domain socket address
+ * @param ops
+ *  Notify ops for the device
+ * @param log
+ *  Log callback for the device
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_register(const char *sock_addr,
+	const struct vfio_user_notify_ops *ops,
+	vfio_user_log log);
+
+/**
+ * Unregister a vfio-user device.
+ *
+ * @param sock_addr
+ *  Unix domain socket address
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_unregister(const char *sock_addr);
+
+/**
+ * Start vfio-user handling for the device.
+ *
+ * This function triggers vfio-user message handling.
+ * @param sock_addr
+ *  Unix domain socket address
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_start(const char *sock_addr);
+
+/**
+ * Stop vfio-user handling for the device.
+ *
+ * This function stops vfio-user message handling.
+ * @param sock_addr
+ *  Unix domain socket address
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_stop(const char *sock_addr);
+
+/**
+ * Get the socket address for a vfio-user device.
+ *
+ * @param dev_id
+ *  Vfio-user device ID
+ * @param buf
+ *  Buffer to store socket address
+ * @param len
+ *  The len of buf
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_get_sock_addr(int dev_id, char *buf, size_t len);
+
+/**
+ * Get the memory table of a vfio-user device.
+ *
+ * @param dev_id
+ *  Vfio-user device ID
+ * @return
+ *  Pointer to memory table on success, NULL on failure
+ */
+struct vfio_user_mem *rte_vfio_user_get_mem_table(int dev_id);
+
+/**
+ * Get the irq set of a vfio-user device.
+ *
+ * @param dev_id
+ *  Vfio-user device ID
+ * @return
+ *  Pointer to irq set on success, NULL on failure
+ */
+struct vfio_user_irq_set *rte_vfio_user_get_irq(int dev_id);
+
+/**
+ * Set the device info for a vfio-user device.
+ *
+ * @param sock_addr
+ *  Unix domain socket address
+ * @param dev_info
+ *  Device info for the vfio-user device
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_set_dev_info(const char *sock_addr,
+	struct vfio_user_dev_info *dev_info);
+
+/**
+ * Set the region info for a vfio-user device.
+ *
+ * @param sock_addr
+ *  Unix domain socket address
+ * @param reg
+ *  Region info for the vfio-user device
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_set_reg_info(const char *sock_addr,
+	struct vfio_user_regions *reg);
+
+/**
+ * Set the irq info for a vfio-user device.
+ *
+ * @param sock_addr
+ *  Unix domain socket address
+ * @param irq
+ *  IRQ info for the vfio-user device
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_set_irq_info(const char *sock_addr,
+	struct vfio_user_irq_info *irq);
+
+/**
+ * Set the device resource for a vfio-user device.
+ *
+ * @param sock_addr
+ *  Unix domain socket address
+ * @param res
+ *  Resource info for the vfio-user device
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vfio_user_set_resource(const char *sock_addr,
+	struct vfio_user_resource *res);
+
+#endif