diff --git a/lib/librte_vhost/trans_af_unix.c b/lib/librte_vhost/trans_af_unix.c
index 5f9ef5a..522823f 100644
--- a/lib/librte_vhost/trans_af_unix.c
+++ b/lib/librte_vhost/trans_af_unix.c
@@ -5,7 +5,14 @@
  */
 
 #include <sys/socket.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
 #include <sys/un.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#ifdef RTE_LIBRTE_VHOST_POSTCOPY
+#include <linux/userfaultfd.h>
+#endif
 #include <fcntl.h>
 
 #include <rte_log.h>
@@ -43,7 +50,7 @@ struct af_unix_socket {
 	struct sockaddr_un un;
 };
 
-int read_vhost_message(int sockfd, struct VhostUserMsg *msg);
+static int read_vhost_message(int sockfd, struct VhostUserMsg *msg);
 static int create_unix_socket(struct vhost_user_socket *vsocket);
 static int vhost_user_start_server(struct vhost_user_socket *vsocket);
 static int vhost_user_start_client(struct vhost_user_socket *vsocket);
@@ -317,7 +324,7 @@ vhost_user_server_new_connection(int fd, void *dat, int *remove __rte_unused)
 }
 
 /* return bytes# of read on success or negative val on failure. */
-int
+static int
 read_vhost_message(int sockfd, struct VhostUserMsg *msg)
 {
 	int ret;
@@ -771,6 +778,178 @@ af_unix_vring_call(struct virtio_net *dev __rte_unused,
 	return 0;
 }
 
+static uint64_t
+get_blk_size(int fd)
+{
+	struct stat stat;
+	int ret;
+
+	ret = fstat(fd, &stat);
+	return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
+}
+
+static int
+af_unix_map_mem_regions(struct virtio_net *dev, struct VhostUserMsg *msg)
+{
+	uint32_t i;
+	struct VhostUserMemory *memory = &msg->payload.memory;
+	struct vhost_user_connection *conn =
+		container_of(dev, struct vhost_user_connection, device);
+
+	for (i = 0; i < dev->mem->nregions; i++) {
+		struct rte_vhost_mem_region *reg = &dev->mem->regions[i];
+		uint64_t mmap_size = reg->mmap_size;
+		uint64_t mmap_offset = mmap_size - reg->size;
+		uint64_t alignment;
+		void *mmap_addr;
+		int populate;
+
+		/* mmap() without flag of MAP_ANONYMOUS, should be called
+		 * with length argument aligned with hugepagesz at older
+		 * longterm version Linux, like 2.6.32 and 3.2.72, or
+		 * mmap() will fail with EINVAL.
+		 *
+		 * to avoid failure, make sure in caller to keep length
+		 * aligned.
+		 */
+		alignment = get_blk_size(reg->fd);
+		if (alignment == (uint64_t)-1) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"couldn't get hugepage size through fstat\n");
+			return -1;
+		}
+		mmap_size = RTE_ALIGN_CEIL(mmap_size, alignment);
+
+		populate = (dev->dequeue_zero_copy) ? MAP_POPULATE : 0;
+		mmap_addr = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
+				 MAP_SHARED | populate, reg->fd, 0);
+
+		if (mmap_addr == MAP_FAILED) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"mmap region %u failed.\n", i);
+			return -1;
+		}
+
+		reg->mmap_addr = mmap_addr;
+		reg->mmap_size = mmap_size;
+		reg->host_user_addr = (uint64_t)(uintptr_t)reg->mmap_addr +
+				      mmap_offset;
+
+		if (dev->dequeue_zero_copy)
+			if (add_guest_pages(dev, reg, alignment) < 0) {
+				RTE_LOG(ERR, VHOST_CONFIG,
+					"adding guest pages to region %u failed.\n",
+					i);
+				return -1;
+			}
+
+		RTE_LOG(INFO, VHOST_CONFIG,
+			"guest memory region %u, size: 0x%" PRIx64 "\n"
+			"\t guest physical addr: 0x%" PRIx64 "\n"
+			"\t guest virtual  addr: 0x%" PRIx64 "\n"
+			"\t host  virtual  addr: 0x%" PRIx64 "\n"
+			"\t mmap addr : 0x%" PRIx64 "\n"
+			"\t mmap size : 0x%" PRIx64 "\n"
+			"\t mmap align: 0x%" PRIx64 "\n"
+			"\t mmap off  : 0x%" PRIx64 "\n",
+			i, reg->size,
+			reg->guest_phys_addr,
+			reg->guest_user_addr,
+			reg->host_user_addr,
+			(uint64_t)(uintptr_t)reg->mmap_addr,
+			reg->mmap_size,
+			alignment,
+			mmap_offset);
+
+		if (dev->postcopy_listening) {
+			/*
+			 * We haven't a better way right now than sharing
+			 * DPDK's virtual address with Qemu, so that Qemu can
+			 * retrieve the region offset when handling userfaults.
+			 */
+			memory->regions[i].userspace_addr =
+				reg->host_user_addr;
+		}
+	}
+
+	if (dev->postcopy_listening) {
+		/* Send the addresses back to qemu */
+		msg->fd_num = 0;
+		/* Send reply */
+		msg->flags &= ~VHOST_USER_VERSION_MASK;
+		msg->flags &= ~VHOST_USER_NEED_REPLY;
+		msg->flags |= VHOST_USER_VERSION;
+		msg->flags |= VHOST_USER_REPLY_MASK;
+		af_unix_send_reply(dev, msg);
+
+		/* Wait for qemu to acknolwedge it's got the addresses
+		 * we've got to wait before we're allowed to generate faults.
+		 */
+		VhostUserMsg ack_msg;
+		if (read_vhost_message(conn->connfd, &ack_msg) <= 0) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"Failed to read qemu ack on postcopy set-mem-table\n");
+			return -1;
+		}
+		if (ack_msg.request.master != VHOST_USER_SET_MEM_TABLE) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"Bad qemu ack on postcopy set-mem-table (%d)\n",
+				ack_msg.request.master);
+			return -1;
+		}
+
+		/* Now userfault register and we can use the memory */
+		for (i = 0; i < memory->nregions; i++) {
+#ifdef RTE_LIBRTE_VHOST_POSTCOPY
+			struct rte_vhost_mem_region *reg = &dev->mem->regions[i];
+			struct uffdio_register reg_struct;
+
+			/*
+			 * Let's register all the mmap'ed area to ensure
+			 * alignment on page boundary.
+			 */
+			reg_struct.range.start =
+				(uint64_t)(uintptr_t)reg->mmap_addr;
+			reg_struct.range.len = reg->mmap_size;
+			reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
+
+			if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER,
+						&reg_struct)) {
+				RTE_LOG(ERR, VHOST_CONFIG,
+					"Failed to register ufd for region %d: (ufd = %d) %s\n",
+					i, dev->postcopy_ufd,
+					strerror(errno));
+				return -1;
+			}
+			RTE_LOG(INFO, VHOST_CONFIG,
+				"\t userfaultfd registered for range : %llx - %llx\n",
+				reg_struct.range.start,
+				reg_struct.range.start +
+				reg_struct.range.len - 1);
+#else
+			return -1;
+#endif
+		}
+	}
+
+	return 0;
+}
+
+static void
+af_unix_unmap_mem_regions(struct virtio_net *dev)
+{
+	uint32_t i;
+	struct rte_vhost_mem_region *reg;
+
+	for (i = 0; i < dev->mem->nregions; i++) {
+		reg = &dev->mem->regions[i];
+		if (reg->host_user_addr) {
+			munmap(reg->mmap_addr, reg->mmap_size);
+			close(reg->fd);
+		}
+	}
+}
+
 const struct vhost_transport_ops af_unix_trans_ops = {
 	.socket_size = sizeof(struct af_unix_socket),
 	.device_size = sizeof(struct vhost_user_connection),
@@ -783,4 +962,6 @@ const struct vhost_transport_ops af_unix_trans_ops = {
 	.send_slave_req = af_unix_send_slave_req,
 	.process_slave_message_reply = af_unix_process_slave_message_reply,
 	.set_slave_req_fd = af_unix_set_slave_req_fd,
+	.map_mem_regions = af_unix_map_mem_regions,
+	.unmap_mem_regions = af_unix_unmap_mem_regions,
 };
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 2213fbe..28038c6 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -415,6 +415,28 @@ struct vhost_transport_ops {
 	 */
 	int (*set_slave_req_fd)(struct virtio_net *dev,
 				struct VhostUserMsg *msg);
+
+	/**
+	 * Map memory table regions in dev->mem->regions[].
+	 *
+	 * @param dev
+	 *  vhost device
+	 * @param msg
+	 *  message
+	 * @return
+	 *  0 on success, -1 on failure
+	 */
+	int (*map_mem_regions)(struct virtio_net *dev,
+				struct VhostUserMsg *msg);
+
+	/**
+	 * Unmap memory table regions in dev->mem->regions[] and free any
+	 * resources, such as file descriptors.
+	 *
+	 * @param dev
+	 *  vhost device
+	 */
+	void (*unmap_mem_regions)(struct virtio_net *dev);
 };
 
 /** The traditional AF_UNIX vhost-user protocol transport. */
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index a4dcba1..ed8dbd8 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -81,17 +81,6 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
 };
 
 static int send_vhost_reply(struct virtio_net *dev, struct VhostUserMsg *msg);
-int read_vhost_message(int sockfd, struct VhostUserMsg *msg);
-
-static uint64_t
-get_blk_size(int fd)
-{
-	struct stat stat;
-	int ret;
-
-	ret = fstat(fd, &stat);
-	return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
-}
 
 /*
  * Reclaim all the outstanding zmbufs for a virtqueue.
@@ -120,7 +109,6 @@ static void
 free_mem_region(struct virtio_net *dev)
 {
 	uint32_t i;
-	struct rte_vhost_mem_region *reg;
 	struct vhost_virtqueue *vq;
 
 	if (!dev || !dev->mem)
@@ -134,13 +122,7 @@ free_mem_region(struct virtio_net *dev)
 		}
 	}
 
-	for (i = 0; i < dev->mem->nregions; i++) {
-		reg = &dev->mem->regions[i];
-		if (reg->host_user_addr) {
-			munmap(reg->mmap_addr, reg->mmap_size);
-			close(reg->fd);
-		}
-	}
+	dev->trans_ops->unmap_mem_regions(dev);
 }
 
 void
@@ -792,7 +774,7 @@ add_one_guest_page(struct virtio_net *dev, uint64_t guest_phys_addr,
 	return 0;
 }
 
-static int
+int
 add_guest_pages(struct virtio_net *dev, struct rte_vhost_mem_region *reg,
 		uint64_t page_size)
 {
@@ -881,18 +863,13 @@ vhost_memory_changed(struct VhostUserMemory *new,
 
 static int
 vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
-			int main_fd)
+			int main_fd __rte_unused)
 {
 	struct virtio_net *dev = *pdev;
 	struct VhostUserMemory *memory = &msg->payload.memory;
 	struct rte_vhost_mem_region *reg;
-	void *mmap_addr;
-	uint64_t mmap_size;
 	uint64_t mmap_offset;
-	uint64_t alignment;
 	uint32_t i;
-	int populate;
-	int fd;
 
 	if (memory->nregions > VHOST_MEMORY_MAX_NREGIONS) {
 		RTE_LOG(ERR, VHOST_CONFIG,
@@ -904,8 +881,11 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 		RTE_LOG(INFO, VHOST_CONFIG,
 			"(%d) memory regions not changed\n", dev->vid);
 
-		for (i = 0; i < memory->nregions; i++)
-			close(msg->fds[i]);
+		for (i = 0; i < memory->nregions; i++) {
+			if (msg->fds[i] >= 0) {
+				close(msg->fds[i]);
+			}
+		}
 
 		return RTE_VHOST_MSG_RESULT_OK;
 	}
@@ -946,13 +926,15 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 	dev->mem->nregions = memory->nregions;
 
 	for (i = 0; i < memory->nregions; i++) {
-		fd  = msg->fds[i];
 		reg = &dev->mem->regions[i];
 
 		reg->guest_phys_addr = memory->regions[i].guest_phys_addr;
 		reg->guest_user_addr = memory->regions[i].userspace_addr;
 		reg->size            = memory->regions[i].memory_size;
-		reg->fd              = fd;
+		reg->mmap_size       = reg->size + memory->regions[i].mmap_offset;
+		reg->mmap_addr       = NULL;
+		reg->host_user_addr  = 0;
+		reg->fd              = msg->fds[i];
 
 		mmap_offset = memory->regions[i].mmap_offset;
 
@@ -962,132 +944,13 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 				"mmap_offset (%#"PRIx64") and memory_size "
 				"(%#"PRIx64") overflow\n",
 				mmap_offset, reg->size);
-			goto err_mmap;
-		}
-
-		mmap_size = reg->size + mmap_offset;
-
-		/* mmap() without flag of MAP_ANONYMOUS, should be called
-		 * with length argument aligned with hugepagesz at older
-		 * longterm version Linux, like 2.6.32 and 3.2.72, or
-		 * mmap() will fail with EINVAL.
-		 *
-		 * to avoid failure, make sure in caller to keep length
-		 * aligned.
-		 */
-		alignment = get_blk_size(fd);
-		if (alignment == (uint64_t)-1) {
-			RTE_LOG(ERR, VHOST_CONFIG,
-				"couldn't get hugepage size through fstat\n");
-			goto err_mmap;
-		}
-		mmap_size = RTE_ALIGN_CEIL(mmap_size, alignment);
-
-		populate = (dev->dequeue_zero_copy) ? MAP_POPULATE : 0;
-		mmap_addr = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
-				 MAP_SHARED | populate, fd, 0);
-
-		if (mmap_addr == MAP_FAILED) {
-			RTE_LOG(ERR, VHOST_CONFIG,
-				"mmap region %u failed.\n", i);
-			goto err_mmap;
+			goto err;
 		}
 
-		reg->mmap_addr = mmap_addr;
-		reg->mmap_size = mmap_size;
-		reg->host_user_addr = (uint64_t)(uintptr_t)mmap_addr +
-				      mmap_offset;
-
-		if (dev->dequeue_zero_copy)
-			if (add_guest_pages(dev, reg, alignment) < 0) {
-				RTE_LOG(ERR, VHOST_CONFIG,
-					"adding guest pages to region %u failed.\n",
-					i);
-				goto err_mmap;
-			}
-
-		RTE_LOG(INFO, VHOST_CONFIG,
-			"guest memory region %u, size: 0x%" PRIx64 "\n"
-			"\t guest physical addr: 0x%" PRIx64 "\n"
-			"\t guest virtual  addr: 0x%" PRIx64 "\n"
-			"\t host  virtual  addr: 0x%" PRIx64 "\n"
-			"\t mmap addr : 0x%" PRIx64 "\n"
-			"\t mmap size : 0x%" PRIx64 "\n"
-			"\t mmap align: 0x%" PRIx64 "\n"
-			"\t mmap off  : 0x%" PRIx64 "\n",
-			i, reg->size,
-			reg->guest_phys_addr,
-			reg->guest_user_addr,
-			reg->host_user_addr,
-			(uint64_t)(uintptr_t)mmap_addr,
-			mmap_size,
-			alignment,
-			mmap_offset);
-
-		if (dev->postcopy_listening) {
-			/*
-			 * We haven't a better way right now than sharing
-			 * DPDK's virtual address with Qemu, so that Qemu can
-			 * retrieve the region offset when handling userfaults.
-			 */
-			memory->regions[i].userspace_addr =
-				reg->host_user_addr;
-		}
 	}
-	if (dev->postcopy_listening) {
-		/* Send the addresses back to qemu */
-		msg->fd_num = 0;
-		send_vhost_reply(dev, msg);
-
-		/* Wait for qemu to acknolwedge it's got the addresses
-		 * we've got to wait before we're allowed to generate faults.
-		 */
-		VhostUserMsg ack_msg;
-		if (read_vhost_message(main_fd, &ack_msg) <= 0) {
-			RTE_LOG(ERR, VHOST_CONFIG,
-				"Failed to read qemu ack on postcopy set-mem-table\n");
-			goto err_mmap;
-		}
-		if (ack_msg.request.master != VHOST_USER_SET_MEM_TABLE) {
-			RTE_LOG(ERR, VHOST_CONFIG,
-				"Bad qemu ack on postcopy set-mem-table (%d)\n",
-				ack_msg.request.master);
-			goto err_mmap;
-		}
-
-		/* Now userfault register and we can use the memory */
-		for (i = 0; i < memory->nregions; i++) {
-#ifdef RTE_LIBRTE_VHOST_POSTCOPY
-			reg = &dev->mem->regions[i];
-			struct uffdio_register reg_struct;
 
-			/*
-			 * Let's register all the mmap'ed area to ensure
-			 * alignment on page boundary.
-			 */
-			reg_struct.range.start =
-				(uint64_t)(uintptr_t)reg->mmap_addr;
-			reg_struct.range.len = reg->mmap_size;
-			reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
-
-			if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER,
-						&reg_struct)) {
-				RTE_LOG(ERR, VHOST_CONFIG,
-					"Failed to register ufd for region %d: (ufd = %d) %s\n",
-					i, dev->postcopy_ufd,
-					strerror(errno));
-				goto err_mmap;
-			}
-			RTE_LOG(INFO, VHOST_CONFIG,
-				"\t userfaultfd registered for range : %llx - %llx\n",
-				reg_struct.range.start,
-				reg_struct.range.start +
-				reg_struct.range.len - 1);
-#else
-			goto err_mmap;
-#endif
-		}
-	}
+	if (dev->trans_ops->map_mem_regions(dev, msg) < 0)
+		goto err;
 
 	for (i = 0; i < dev->nr_vring; i++) {
 		struct vhost_virtqueue *vq = dev->virtqueue[i];
@@ -1103,7 +966,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 			dev = translate_ring_addresses(dev, i);
 			if (!dev) {
 				dev = *pdev;
-				goto err_mmap;
+				goto err;
 			}
 
 			*pdev = dev;
@@ -1114,7 +977,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 
 	return RTE_VHOST_MSG_RESULT_OK;
 
-err_mmap:
+err:
 	free_mem_region(dev);
 	rte_free(dev->mem);
 	dev->mem = NULL;
diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
index 0169bd2..200e47b 100644
--- a/lib/librte_vhost/vhost_user.h
+++ b/lib/librte_vhost/vhost_user.h
@@ -147,6 +147,9 @@ typedef struct VhostUserMsg {
 
 /* vhost_user.c */
 int vhost_user_msg_handler(int vid, int fd, const struct VhostUserMsg *msg);
+int add_guest_pages(struct virtio_net *dev,
+		   struct rte_vhost_mem_region *reg,
+		   uint64_t page_size);
 int vhost_user_iotlb_miss(struct virtio_net *dev, uint64_t iova, uint8_t perm);
 
 #endif
