diff --git a/lib/librte_vfio_user/rte_vfio_user.h b/lib/librte_vfio_user/rte_vfio_user.h
index 0d4f6c1be2..8a999c7aa0 100644
--- a/lib/librte_vfio_user/rte_vfio_user.h
+++ b/lib/librte_vfio_user/rte_vfio_user.h
@@ -5,13 +5,35 @@
 #ifndef _RTE_VFIO_USER_H
 #define _RTE_VFIO_USER_H
 
+#include <linux/vfio.h>
+
 #include <rte_compat.h>
 
+struct rte_vfio_user_reg_info;
+
+typedef ssize_t (*rte_vfio_user_reg_acc_t)(struct rte_vfio_user_reg_info *reg,
+		char *buf, size_t count, loff_t pos, bool iswrite);
+
+struct rte_vfio_user_reg_info {
+	rte_vfio_user_reg_acc_t rw;
+	void *base;
+	int fd;
+	struct vfio_region_info *info;
+	void *priv;
+};
+
+struct rte_vfio_user_regions {
+	uint32_t reg_num;
+	struct rte_vfio_user_reg_info reg_info[];
+};
+
 /**
  *  Below APIs are for vfio-user server (device provider) to use:
  *	*rte_vfio_user_register
  *	*rte_vfio_user_unregister
  *	*rte_vfio_user_start
+ *	*rte_vfio_user_set_dev_info
+ *	*rte_vfio_user_set_reg_info
  */
 
 /**
@@ -48,4 +70,42 @@ int rte_vfio_user_unregister(const char *sock_addr);
 __rte_experimental
 int rte_vfio_user_start(const char *sock_addr);
 
+/**
+ * Set the device information for a vfio-user device.
+ *
+ * This information must be set before calling rte_vfio_user_start, and should
+ * not be updated after start. Update after start can be done by unregistration
+ * and re-registration, and then the device-level change can be detected by
+ * vfio-user client.
+ *
+ * @param sock_addr
+ *   Unix domain socket address
+ * @param dev_info
+ *   Device information for the vfio-user device
+ * @return
+ *   0 on success, -1 on failure
+ */
+__rte_experimental
+int rte_vfio_user_set_dev_info(const char *sock_addr,
+	struct vfio_device_info *dev_info);
+
+/**
+ * Set the region information for a vfio-user device.
+ *
+ * This information must be set before calling rte_vfio_user_start, and should
+ * not be updated after start. Update after start can be done by unregistration
+ * and re-registration, and then the device-level change can be detected by
+ * vfio-user client.
+ *
+ * @param sock_addr
+ *   Unix domain socket address
+ * @param reg
+ *   Region information for the vfio-user device
+ * @return
+ *   0 on success, -1 on failure
+ */
+__rte_experimental
+int rte_vfio_user_set_reg_info(const char *sock_addr,
+	struct rte_vfio_user_regions *reg);
+
 #endif
diff --git a/lib/librte_vfio_user/version.map b/lib/librte_vfio_user/version.map
index e53095eda8..0f4f5acba5 100644
--- a/lib/librte_vfio_user/version.map
+++ b/lib/librte_vfio_user/version.map
@@ -4,6 +4,8 @@ EXPERIMENTAL {
 	rte_vfio_user_register;
 	rte_vfio_user_unregister;
 	rte_vfio_user_start;
+	rte_vfio_user_set_dev_info;
+	rte_vfio_user_set_reg_info;
 
 	local: *;
 };
diff --git a/lib/librte_vfio_user/vfio_user_base.c b/lib/librte_vfio_user/vfio_user_base.c
index bbad553e0a..4960589519 100644
--- a/lib/librte_vfio_user/vfio_user_base.c
+++ b/lib/librte_vfio_user/vfio_user_base.c
@@ -13,6 +13,18 @@ int vfio_user_log_level;
 const char *vfio_user_msg_str[VFIO_USER_MAX] = {
 	[VFIO_USER_NONE] = "VFIO_USER_NONE",
 	[VFIO_USER_VERSION] = "VFIO_USER_VERSION",
+	[VFIO_USER_DMA_MAP] = "VFIO_USER_DMA_MAP",
+	[VFIO_USER_DMA_UNMAP] = "VFIO_USER_DMA_UNMAP",
+	[VFIO_USER_DEVICE_GET_INFO] = "VFIO_USER_DEVICE_GET_INFO",
+	[VFIO_USER_DEVICE_GET_REGION_INFO] = "VFIO_USER_GET_REGION_INFO",
+	[VFIO_USER_DEVICE_GET_IRQ_INFO] = "VFIO_USER_DEVICE_GET_IRQ_INFO",
+	[VFIO_USER_DEVICE_SET_IRQS] = "VFIO_USER_DEVICE_SET_IRQS",
+	[VFIO_USER_REGION_READ] = "VFIO_USER_REGION_READ",
+	[VFIO_USER_REGION_WRITE] = "VFIO_USER_REGION_WRITE",
+	[VFIO_USER_DMA_READ] = "VFIO_USER_DMA_READ",
+	[VFIO_USER_DMA_WRITE] = "VFIO_USER_DMA_WRITE",
+	[VFIO_USER_VM_INTERRUPT] = "VFIO_USER_VM_INTERRUPT",
+	[VFIO_USER_DEVICE_RESET] = "VFIO_USER_DEVICE_RESET",
 };
 
 inline void vfio_user_close_msg_fds(VFIO_USER_MSG *msg)
diff --git a/lib/librte_vfio_user/vfio_user_base.h b/lib/librte_vfio_user/vfio_user_base.h
index 926cecfa7a..0d8abde816 100644
--- a/lib/librte_vfio_user/vfio_user_base.h
+++ b/lib/librte_vfio_user/vfio_user_base.h
@@ -11,6 +11,8 @@
 
 #define VFIO_USER_VERSION_MAJOR 1
 #define VFIO_USER_VERSION_MINOR 0
+#define VFIO_USER_MAX_RSVD 512
+#define VFIO_USER_MAX_RW_DATA 512
 #define VFIO_USER_MAX_FD 1024
 #define VFIO_USER_MAX_VERSION_DATA 512
 
@@ -30,7 +32,19 @@ struct vfio_user_socket {
 typedef enum VFIO_USER_CMD_TYPE {
 	VFIO_USER_NONE = 0,
 	VFIO_USER_VERSION = 1,
-	VFIO_USER_MAX = 2,
+	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_version {
@@ -40,6 +54,19 @@ struct vfio_user_version {
 	uint8_t ver_data[VFIO_USER_MAX_VERSION_DATA];
 };
 
+struct vfio_user_reg {
+	struct vfio_region_info reg_info;
+	/* Reserved for region capability list */
+	uint8_t rsvd[VFIO_USER_MAX_RSVD];
+};
+
+struct vfio_user_reg_rw {
+	uint64_t reg_offset;
+	uint32_t reg_idx;
+	uint32_t size;
+	char data[VFIO_USER_MAX_RW_DATA];
+};
+
 typedef struct vfio_user_msg {
 	uint16_t msg_id;
 	uint16_t cmd;
@@ -52,6 +79,9 @@ typedef struct vfio_user_msg {
 	uint32_t err;				/* Valid in reply, optional */
 	union {
 		struct vfio_user_version ver;
+		struct vfio_device_info dev_info;
+		struct vfio_user_reg reg_info;
+		struct vfio_user_reg_rw reg_rw;
 	} payload;
 	int fds[VFIO_USER_MAX_FD];
 	int fd_num;
diff --git a/lib/librte_vfio_user/vfio_user_server.c b/lib/librte_vfio_user/vfio_user_server.c
index 545c779fb0..d882f2ccbe 100644
--- a/lib/librte_vfio_user/vfio_user_server.c
+++ b/lib/librte_vfio_user/vfio_user_server.c
@@ -5,6 +5,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <pthread.h>
+#include <inttypes.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 
@@ -38,9 +39,155 @@ static int vfio_user_negotiate_version(struct vfio_user_server *dev,
 		return -ENOTSUP;
 }
 
+static int vfio_user_device_get_info(struct vfio_user_server *dev,
+	VFIO_USER_MSG *msg)
+{
+	struct vfio_device_info *dev_info = &msg->payload.dev_info;
+
+	if (vfio_user_check_msg_fdnum(msg, 0) != 0)
+		return -EINVAL;
+
+	if (msg->size != sizeof(*dev_info) + VFIO_USER_MSG_HDR_SIZE) {
+		VFIO_USER_LOG(ERR, "Invalid message for get dev info\n");
+		return -EINVAL;
+	}
+
+	memcpy(dev_info, dev->dev_info, sizeof(*dev_info));
+
+	VFIO_USER_LOG(DEBUG, "Device info: argsz(0x%x), flags(0x%x), "
+		"regions(%u), irqs(%u)\n", dev_info->argsz, dev_info->flags,
+		dev_info->num_regions, dev_info->num_irqs);
+
+	return 0;
+}
+
+static int vfio_user_device_get_reg_info(struct vfio_user_server *dev,
+	VFIO_USER_MSG *msg)
+{
+	struct vfio_user_reg *reg = &msg->payload.reg_info;
+	struct rte_vfio_user_reg_info *reg_info;
+	struct vfio_region_info *vinfo;
+
+	if (vfio_user_check_msg_fdnum(msg, 0) != 0)
+		return -EINVAL;
+
+	if (msg->size > sizeof(*reg) + VFIO_USER_MSG_HDR_SIZE ||
+		dev->reg->reg_num <= reg->reg_info.index) {
+		VFIO_USER_LOG(ERR, "Invalid message for get dev info\n");
+		return -EINVAL;
+	}
+
+	reg_info = &dev->reg->reg_info[reg->reg_info.index];
+	vinfo = reg_info->info;
+	memcpy(reg, vinfo, vinfo->argsz);
+
+	if (reg_info->fd != -1) {
+		msg->fd_num = 1;
+		msg->fds[0] = reg_info->fd;
+	}
+
+	VFIO_USER_LOG(DEBUG, "Region(%u) info: addr(0x%" PRIx64 "), fd(%d), "
+		"sz(0x%llx), argsz(0x%x), c_off(0x%x), flags(0x%x) "
+		"off(0x%llx)\n", vinfo->index, (uint64_t)reg_info->base,
+		reg_info->fd, vinfo->size, vinfo->argsz, vinfo->cap_offset,
+		vinfo->flags, vinfo->offset);
+
+	return 0;
+}
+
+static int vfio_user_region_read(struct vfio_user_server *dev,
+	VFIO_USER_MSG *msg)
+{
+	struct vfio_user_reg_rw *rw = &msg->payload.reg_rw;
+	struct rte_vfio_user_regions *reg = dev->reg;
+	struct rte_vfio_user_reg_info *reg_info;
+	size_t count;
+
+	if (vfio_user_check_msg_fdnum(msg, 0) != 0)
+		return -EINVAL;
+
+	reg_info = &reg->reg_info[rw->reg_idx];
+
+	if (rw->reg_idx >= reg->reg_num ||
+		rw->size > VFIO_USER_MAX_RW_DATA ||
+		rw->reg_offset >= reg_info->info->size ||
+		rw->reg_offset + rw->size > reg_info->info->size) {
+		VFIO_USER_LOG(ERR, "Invalid read region request\n");
+		rw->size = 0;
+		return 0;
+	}
+
+	VFIO_USER_LOG(DEBUG, "Read Region(%u): offset(0x%" PRIx64 "),"
+		"size(0x%x)\n", rw->reg_idx, rw->reg_offset, rw->size);
+
+	if (reg_info->rw) {
+		count = reg_info->rw(reg_info, msg->payload.reg_rw.data,
+				rw->size, rw->reg_offset, 0);
+		rw->size = count;
+		msg->size += count;
+		return 0;
+	}
+
+	memcpy(&msg->payload.reg_rw.data,
+		(uint8_t *)reg_info->base + rw->reg_offset, rw->size);
+	msg->size += rw->size;
+	return 0;
+}
+
+static int vfio_user_region_write(struct vfio_user_server *dev,
+	VFIO_USER_MSG *msg)
+{
+	struct vfio_user_reg_rw *rw = &msg->payload.reg_rw;
+	struct rte_vfio_user_regions *reg = dev->reg;
+	struct rte_vfio_user_reg_info *reg_info;
+	size_t count;
+
+	if (vfio_user_check_msg_fdnum(msg, 0) != 0)
+		return -EINVAL;
+
+	if (rw->reg_idx >= reg->reg_num) {
+		VFIO_USER_LOG(ERR, "Write a non-existed region\n");
+		return -EINVAL;
+	}
+
+	reg_info = &reg->reg_info[rw->reg_idx];
+
+	VFIO_USER_LOG(DEBUG, "Write Region(%u): offset(0x%" PRIx64 "),"
+		"size(0x%x)\n", rw->reg_idx, rw->reg_offset, rw->size);
+
+	if (reg_info->rw) {
+		count = reg_info->rw(reg_info, msg->payload.reg_rw.data,
+				rw->size, rw->reg_offset, 1);
+		if (count < rw->size) {
+			VFIO_USER_LOG(ERR, "Write region %d failed\n",
+				rw->reg_idx);
+			return -EIO;
+		}
+		rw->size = 0;
+		return 0;
+	}
+
+	memcpy((uint8_t *)reg_info->base + rw->reg_offset,
+		&msg->payload.reg_rw.data, rw->size);
+	rw->size = 0;
+	return 0;
+}
+
 static vfio_user_msg_handler_t vfio_user_msg_handlers[VFIO_USER_MAX] = {
 	[VFIO_USER_NONE] = NULL,
 	[VFIO_USER_VERSION] = vfio_user_negotiate_version,
+	[VFIO_USER_DMA_MAP] = NULL,
+	[VFIO_USER_DMA_UNMAP] = NULL,
+	[VFIO_USER_DEVICE_GET_INFO] = vfio_user_device_get_info,
+	[VFIO_USER_DEVICE_GET_REGION_INFO] = vfio_user_device_get_reg_info,
+	[VFIO_USER_DEVICE_GET_IRQ_INFO] = NULL,
+	[VFIO_USER_DEVICE_SET_IRQS] = NULL,
+	[VFIO_USER_REGION_READ] = vfio_user_region_read,
+	[VFIO_USER_REGION_WRITE] = vfio_user_region_write,
+	[VFIO_USER_DMA_READ] = NULL,
+	[VFIO_USER_DMA_WRITE] = NULL,
+	[VFIO_USER_VM_INTERRUPT] = NULL,
+	[VFIO_USER_DEVICE_RESET] = NULL,
 };
 
 static struct vfio_user_server_socket *
@@ -549,6 +696,13 @@ vfio_user_start_server(struct vfio_user_server_socket *sk)
 		return 0;
 	}
 
+	/* All the info must be set before start */
+	if (!dev->dev_info || !dev->reg) {
+		VFIO_USER_LOG(ERR, "Failed to start, "
+			"dev/reg info must be set before start\n");
+		return -1;
+	}
+
 	unlink(path);
 	ret = bind(fd, (struct sockaddr *)&sk->un, sizeof(sk->un));
 	if (ret < 0) {
@@ -688,3 +842,81 @@ int rte_vfio_user_start(const char *sock_addr)
 	pthread_mutex_unlock(&vfio_ep_sock.mutex);
 	return -1;
 }
+
+int rte_vfio_user_set_dev_info(const char *sock_addr,
+	struct vfio_device_info *dev_info)
+{
+	struct vfio_user_server *dev;
+	struct vfio_user_server_socket *sk;
+	int dev_id;
+
+	if (!dev_info)
+		return -1;
+
+	pthread_mutex_lock(&vfio_ep_sock.mutex);
+	sk = find_vfio_user_socket(sock_addr);
+	pthread_mutex_unlock(&vfio_ep_sock.mutex);
+
+	if (!sk) {
+		VFIO_USER_LOG(ERR, "Failed to set device info with sock_addr "
+			"%s: addr not registered.\n", sock_addr);
+		return -1;
+	}
+
+	dev_id = sk->sock.dev_id;
+	dev = vfio_user_get_device(dev_id);
+	if (!dev) {
+		VFIO_USER_LOG(ERR, "Failed to set device info:"
+			"device %d not found.\n", dev_id);
+		return -1;
+	}
+
+	if (dev->started) {
+		VFIO_USER_LOG(ERR, "Failed to set device info for device %d\n"
+			 ", device already started\n", dev_id);
+		return -1;
+	}
+
+	dev->dev_info = dev_info;
+
+	return 0;
+}
+
+int rte_vfio_user_set_reg_info(const char *sock_addr,
+	struct rte_vfio_user_regions *reg)
+{
+	struct vfio_user_server *dev;
+	struct vfio_user_server_socket *sk;
+	int dev_id;
+
+	if (!reg)
+		return -1;
+
+	pthread_mutex_lock(&vfio_ep_sock.mutex);
+	sk = find_vfio_user_socket(sock_addr);
+	pthread_mutex_unlock(&vfio_ep_sock.mutex);
+
+	if (!sk) {
+		VFIO_USER_LOG(ERR, "Failed to set region info with sock_addr:"
+			"%s: addr not registered.\n", sock_addr);
+		return -1;
+	}
+
+	dev_id = sk->sock.dev_id;
+	dev = vfio_user_get_device(dev_id);
+	if (!dev) {
+		VFIO_USER_LOG(ERR, "Failed to set region info:"
+			"device %d not found.\n", dev_id);
+		return -1;
+	}
+
+	if (dev->started) {
+		VFIO_USER_LOG(ERR, "Failed to set region info for device %d\n"
+			 ", device already started\n", dev_id);
+		return -1;
+	}
+
+	dev->reg = reg;
+
+	return 0;
+}
diff --git a/lib/librte_vfio_user/vfio_user_server.h b/lib/librte_vfio_user/vfio_user_server.h
index 00e3f6353d..e8fb61cb3e 100644
--- a/lib/librte_vfio_user/vfio_user_server.h
+++ b/lib/librte_vfio_user/vfio_user_server.h
@@ -16,6 +16,8 @@ struct vfio_user_server {
 	uint32_t msg_id;
 	char sock_addr[PATH_MAX];
 	struct vfio_user_version ver;
+	struct vfio_device_info *dev_info;
+	struct rte_vfio_user_regions *reg;
 };
 
 typedef int (*event_handler)(int fd, void *data);
