diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 382b9732b8..bfb444f211 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1097,6 +1097,96 @@ vhost_user_postcopy_register(struct virtio_net *dev, int main_fd,
 	return 0;
 }
 
+static int
+vhost_user_mmap_region(struct virtio_net *dev,
+		struct rte_vhost_mem_region *region,
+		uint64_t mmap_offset)
+{
+	void *mmap_addr;
+	uint64_t mmap_size;
+	uint64_t alignment;
+	int populate;
+
+	/* Check for memory_size + mmap_offset overflow */
+	if (mmap_offset >= -region->size) {
+		VHOST_LOG_CONFIG(ERR,
+				"mmap_offset (%#"PRIx64") and memory_size "
+				"(%#"PRIx64") overflow\n",
+				mmap_offset, region->size);
+		return -1;
+	}
+
+	mmap_size = region->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(region->fd);
+	if (alignment == (uint64_t)-1) {
+		VHOST_LOG_CONFIG(ERR,
+				"couldn't get hugepage size through fstat\n");
+		return -1;
+	}
+	mmap_size = RTE_ALIGN_CEIL(mmap_size, alignment);
+	if (mmap_size == 0) {
+		/*
+		 * It could happen if initial mmap_size + alignment overflows
+		 * the sizeof uint64, which could happen if either mmap_size or
+		 * alignment value is wrong.
+		 *
+		 * mmap() kernel implementation would return an error, but
+		 * better catch it before and provide useful info in the logs.
+		 */
+		VHOST_LOG_CONFIG(ERR, "mmap size (0x%" PRIx64 ") "
+				"or alignment (0x%" PRIx64 ") is invalid\n",
+				region->size + mmap_offset, alignment);
+		return -1;
+	}
+
+	populate = dev->async_copy ? MAP_POPULATE : 0;
+	mmap_addr = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
+			MAP_SHARED | populate, region->fd, 0);
+
+	if (mmap_addr == MAP_FAILED) {
+		VHOST_LOG_CONFIG(ERR, "mmap failed (%s).\n", strerror(errno));
+		return -1;
+	}
+
+	region->mmap_addr = mmap_addr;
+	region->mmap_size = mmap_size;
+	region->host_user_addr = (uint64_t)(uintptr_t)mmap_addr + mmap_offset;
+
+	if (dev->async_copy)
+		if (add_guest_pages(dev, region, alignment) < 0) {
+			VHOST_LOG_CONFIG(ERR,
+					"adding guest pages to region failed.\n");
+			return -1;
+		}
+
+	VHOST_LOG_CONFIG(INFO,
+			"guest memory region 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",
+			region->size,
+			region->guest_phys_addr,
+			region->guest_user_addr,
+			region->host_user_addr,
+			(uint64_t)(uintptr_t)mmap_addr,
+			mmap_size,
+			alignment,
+			mmap_offset);
+
+	return 0;
+}
+
 static int
 vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 			int main_fd)
@@ -1104,12 +1194,9 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 	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;
 
 	if (validate_msg_fds(msg, memory->nregions) != 0)
 		return RTE_VHOST_MSG_RESULT_ERR;
@@ -1171,7 +1258,6 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 			dev->vid);
 		goto free_guest_pages;
 	}
-	dev->mem->nregions = memory->nregions;
 
 	for (i = 0; i < memory->nregions; i++) {
 		reg = &dev->mem->regions[i];
@@ -1189,88 +1275,12 @@ vhost_user_set_mem_table(struct virtio_net **pdev, struct VhostUserMsg *msg,
 
 		mmap_offset = memory->regions[i].mmap_offset;
 
-		/* Check for memory_size + mmap_offset overflow */
-		if (mmap_offset >= -reg->size) {
-			VHOST_LOG_CONFIG(ERR,
-				"mmap_offset (%#"PRIx64") and memory_size "
-				"(%#"PRIx64") overflow\n",
-				mmap_offset, reg->size);
-			goto free_mem_table;
-		}
-
-		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(reg->fd);
-		if (alignment == (uint64_t)-1) {
-			VHOST_LOG_CONFIG(ERR,
-				"couldn't get hugepage size through fstat\n");
-			goto free_mem_table;
-		}
-		mmap_size = RTE_ALIGN_CEIL(mmap_size, alignment);
-		if (mmap_size == 0) {
-			/*
-			 * It could happen if initial mmap_size + alignment
-			 * overflows the sizeof uint64, which could happen if
-			 * either mmap_size or alignment value is wrong.
-			 *
-			 * mmap() kernel implementation would return an error,
-			 * but better catch it before and provide useful info
-			 * in the logs.
-			 */
-			VHOST_LOG_CONFIG(ERR, "mmap size (0x%" PRIx64 ") "
-					"or alignment (0x%" PRIx64 ") is invalid\n",
-					reg->size + mmap_offset, alignment);
-			goto free_mem_table;
-		}
-
-		populate = dev->async_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) {
-			VHOST_LOG_CONFIG(ERR,
-				"mmap region %u failed.\n", i);
+		if (vhost_user_mmap_region(dev, reg, mmap_offset) < 0) {
+			VHOST_LOG_CONFIG(ERR, "Failed to mmap region %u\n", i);
 			goto free_mem_table;
 		}
 
-		reg->mmap_addr = mmap_addr;
-		reg->mmap_size = mmap_size;
-		reg->host_user_addr = (uint64_t)(uintptr_t)mmap_addr +
-				      mmap_offset;
-
-		if (dev->async_copy)
-			if (add_guest_pages(dev, reg, alignment) < 0) {
-				VHOST_LOG_CONFIG(ERR,
-					"adding guest pages to region %u failed.\n",
-					i);
-				goto free_mem_table;
-			}
-
-		VHOST_LOG_CONFIG(INFO,
-			"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);
+		dev->mem->nregions++;
 	}
 
 	if (vhost_user_postcopy_register(dev, main_fd, msg) < 0)
