diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index b5cac8875..03a0095f2 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -516,8 +516,8 @@ spdk_vhost_session_find_by_vid(int vid)
 	struct spdk_vhost_dev *vdev;
 
 	TAILQ_FOREACH(vdev, &g_spdk_vhost_devices, tailq) {
-		if (vdev->session.vid == vid) {
-			return &vdev->session;
+		if (vdev->session && vdev->session->vid == vid) {
+			return vdev->session;
 		}
 	}
 
@@ -750,7 +750,6 @@ spdk_vhost_dev_register(struct spdk_vhost_dev *vdev, const char *name, const cha
 	vdev->name = strdup(name);
 	vdev->path = strdup(path);
 	vdev->id = ctrlr_num++;
-	vdev->session.vid = -1;
 	vdev->lcore = -1;
 	vdev->cpumask = cpumask;
 	vdev->registered = true;
@@ -775,7 +774,7 @@ out:
 int
 spdk_vhost_dev_unregister(struct spdk_vhost_dev *vdev)
 {
-	if (vdev->session.vid != -1) {
+	if (vdev->session) {
 		SPDK_ERRLOG("Controller %s has still valid connection.\n", vdev->name);
 		return -EBUSY;
 	}
@@ -1267,16 +1266,23 @@ new_connection(int vid)
 		return -1;
 	}
 
-	/* since pollers are not running it safe not to use spdk_event here */
-	vsession = &vdev->session;
-	if (vsession->vid != -1) {
-		SPDK_ERRLOG("Session with vid %d already exists.\n", vid);
+	if (vdev->session != NULL) {
+		SPDK_ERRLOG("Device %s is already connected.\n", vdev->name);
+		pthread_mutex_unlock(&g_spdk_vhost_mutex);
+		return -1;
+	}
+
+	vsession = spdk_dma_zmalloc(sizeof(struct spdk_vhost_session),
+				    SPDK_CACHE_LINE_SIZE, NULL);
+	if (vsession == NULL) {
+		SPDK_ERRLOG("spdk_dma_zmalloc failed\n");
 		pthread_mutex_unlock(&g_spdk_vhost_mutex);
 		return -1;
 	}
 
 	vsession->vdev = vdev;
 	vsession->vid = vid;
+	vdev->session = vsession;
 	pthread_mutex_unlock(&g_spdk_vhost_mutex);
 	return 0;
 }
@@ -1294,8 +1300,8 @@ destroy_connection(int vid)
 		return;
 	}
 
-	/* since pollers are not running it safe not to use spdk_event here */
-	vsession->vid = -1;
+	vsession->vdev->session = NULL;
+	spdk_dma_free(vsession);
 	pthread_mutex_unlock(&g_spdk_vhost_mutex);
 }
 
diff --git a/lib/vhost/vhost_blk.c b/lib/vhost/vhost_blk.c
index 74aa5be95..90ee633e0 100644
--- a/lib/vhost/vhost_blk.c
+++ b/lib/vhost/vhost_blk.c
@@ -85,8 +85,8 @@ process_blk_request(struct spdk_vhost_blk_task *task, struct spdk_vhost_blk_dev
 static void
 blk_task_finish(struct spdk_vhost_blk_task *task)
 {
-	assert(task->bvdev->vdev.session.task_cnt > 0);
-	task->bvdev->vdev.session.task_cnt--;
+	assert(task->bvdev->vdev.session->task_cnt > 0);
+	task->bvdev->vdev.session->task_cnt--;
 	task->used = false;
 }
 
@@ -97,7 +97,7 @@ invalid_blk_request(struct spdk_vhost_blk_task *task, uint8_t status)
 		*task->status = status;
 	}
 
-	spdk_vhost_vq_used_ring_enqueue(&task->bvdev->vdev.session, task->vq, task->req_idx,
+	spdk_vhost_vq_used_ring_enqueue(task->bvdev->vdev.session, task->vq, task->req_idx,
 					task->used_len);
 	blk_task_finish(task);
 	SPDK_DEBUGLOG(SPDK_LOG_VHOST_BLK_DATA, "Invalid request (status=%" PRIu8")\n", status);
@@ -119,7 +119,7 @@ blk_iovs_setup(struct spdk_vhost_dev *vdev, struct spdk_vhost_virtqueue *vq, uin
 	uint32_t desc_table_size, len = 0;
 	int rc;
 
-	rc = spdk_vhost_vq_get_desc(&vdev->session, vq, req_idx, &desc, &desc_table, &desc_table_size);
+	rc = spdk_vhost_vq_get_desc(vdev->session, vq, req_idx, &desc, &desc_table, &desc_table_size);
 	if (rc != 0) {
 		SPDK_ERRLOG("%s: Invalid descriptor at index %"PRIu16".\n", vdev->name, req_idx);
 		return -1;
@@ -136,7 +136,7 @@ blk_iovs_setup(struct spdk_vhost_dev *vdev, struct spdk_vhost_virtqueue *vq, uin
 			return -1;
 		}
 
-		if (spdk_unlikely(spdk_vhost_vring_desc_to_iov(&vdev->session, iovs, &cnt, desc))) {
+		if (spdk_unlikely(spdk_vhost_vring_desc_to_iov(vdev->session, iovs, &cnt, desc))) {
 			SPDK_DEBUGLOG(SPDK_LOG_VHOST_BLK, "Invalid descriptor %" PRIu16" (req_idx = %"PRIu16").\n",
 				      req_idx, cnt);
 			return -1;
@@ -174,7 +174,7 @@ static void
 blk_request_finish(bool success, struct spdk_vhost_blk_task *task)
 {
 	*task->status = success ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR;
-	spdk_vhost_vq_used_ring_enqueue(&task->bvdev->vdev.session, task->vq, task->req_idx,
+	spdk_vhost_vq_used_ring_enqueue(task->bvdev->vdev.session, task->vq, task->req_idx,
 					task->used_len);
 	SPDK_DEBUGLOG(SPDK_LOG_VHOST_BLK, "Finished task (%p) req_idx=%d\n status: %s\n", task,
 		      task->req_idx, success ? "OK" : "FAIL");
@@ -377,7 +377,7 @@ static void
 process_vq(struct spdk_vhost_blk_dev *bvdev, struct spdk_vhost_virtqueue *vq)
 {
 	struct spdk_vhost_blk_task *task;
-	struct spdk_vhost_session *vsession = &bvdev->vdev.session;
+	struct spdk_vhost_session *vsession = bvdev->vdev.session;
 	int rc;
 	uint16_t reqs[32];
 	uint16_t reqs_cnt, i;
@@ -427,7 +427,7 @@ static int
 vdev_worker(void *arg)
 {
 	struct spdk_vhost_blk_dev *bvdev = arg;
-	struct spdk_vhost_session *vsession = &bvdev->vdev.session;
+	struct spdk_vhost_session *vsession = bvdev->vdev.session;
 	uint16_t q_idx;
 
 	for (q_idx = 0; q_idx < vsession->max_queues; q_idx++) {
@@ -442,7 +442,7 @@ vdev_worker(void *arg)
 static void
 no_bdev_process_vq(struct spdk_vhost_blk_dev *bvdev, struct spdk_vhost_virtqueue *vq)
 {
-	struct spdk_vhost_session *vsession = &bvdev->vdev.session;
+	struct spdk_vhost_session *vsession = bvdev->vdev.session;
 	struct iovec iovs[SPDK_VHOST_IOVS_MAX];
 	uint32_t length;
 	uint16_t iovcnt, req_idx;
@@ -464,7 +464,7 @@ static int
 no_bdev_vdev_worker(void *arg)
 {
 	struct spdk_vhost_blk_dev *bvdev = arg;
-	struct spdk_vhost_session *vsession = &bvdev->vdev.session;
+	struct spdk_vhost_session *vsession = bvdev->vdev.session;
 	uint16_t q_idx;
 
 	for (q_idx = 0; q_idx < vsession->max_queues; q_idx++) {
@@ -534,7 +534,7 @@ bdev_remove_cb(void *remove_ctx)
 static void
 free_task_pool(struct spdk_vhost_blk_dev *bvdev)
 {
-	struct spdk_vhost_session *vsession = &bvdev->vdev.session;
+	struct spdk_vhost_session *vsession = bvdev->vdev.session;
 	struct spdk_vhost_virtqueue *vq;
 	uint16_t i;
 
@@ -552,7 +552,7 @@ free_task_pool(struct spdk_vhost_blk_dev *bvdev)
 static int
 alloc_task_pool(struct spdk_vhost_blk_dev *bvdev)
 {
-	struct spdk_vhost_session *vsession = &bvdev->vdev.session;
+	struct spdk_vhost_session *vsession = bvdev->vdev.session;
 	struct spdk_vhost_virtqueue *vq;
 	struct spdk_vhost_blk_task *task;
 	uint32_t task_cnt;
@@ -602,7 +602,7 @@ static int
 spdk_vhost_blk_start(struct spdk_vhost_dev *vdev, void *event_ctx)
 {
 	struct spdk_vhost_blk_dev *bvdev;
-	struct spdk_vhost_session *vsession = &vdev->session;
+	struct spdk_vhost_session *vsession = vdev->session;
 	int i, rc = 0;
 
 	bvdev = to_blk_dev(vdev);
@@ -650,7 +650,7 @@ static int
 destroy_device_poller_cb(void *arg)
 {
 	struct spdk_vhost_blk_dev *bvdev = arg;
-	struct spdk_vhost_session *vsession = &bvdev->vdev.session;
+	struct spdk_vhost_session *vsession = bvdev->vdev.session;
 	int i;
 
 	if (vsession->task_cnt > 0) {
diff --git a/lib/vhost/vhost_internal.h b/lib/vhost/vhost_internal.h
index f78e67e89..9ebedf00d 100644
--- a/lib/vhost/vhost_internal.h
+++ b/lib/vhost/vhost_internal.h
@@ -133,6 +133,23 @@ struct spdk_vhost_dev_backend {
 	int (*remove_device)(struct spdk_vhost_dev *vdev);
 };
 
+struct spdk_vhost_session {
+	struct spdk_vhost_dev *vdev;
+
+	/* rte_vhost connection ID. */
+	int vid;
+
+	struct rte_vhost_memory *mem;
+
+	int task_cnt;
+
+	uint16_t max_queues;
+
+	uint64_t negotiated_features;
+
+	struct spdk_vhost_virtqueue virtqueue[SPDK_VHOST_MAX_VQUEUES];
+};
+
 struct spdk_vhost_dev {
 	char *name;
 	char *path;
@@ -164,22 +181,7 @@ struct spdk_vhost_dev {
 	uint64_t stats_check_interval;
 
 	/* Active connection to the device */
-	struct spdk_vhost_session {
-		struct spdk_vhost_dev *vdev;
-
-		/* rte_vhost connection ID. */
-		int vid;
-
-		struct rte_vhost_memory *mem;
-
-		int task_cnt;
-
-		uint16_t max_queues;
-
-		uint64_t negotiated_features;
-
-		struct spdk_vhost_virtqueue virtqueue[SPDK_VHOST_MAX_VQUEUES];
-	} session;
+	struct spdk_vhost_session *session;
 
 	TAILQ_ENTRY(spdk_vhost_dev) tailq;
 };
diff --git a/lib/vhost/vhost_nvme.c b/lib/vhost/vhost_nvme.c
index 98ab48240..c26640c46 100644
--- a/lib/vhost/vhost_nvme.c
+++ b/lib/vhost/vhost_nvme.c
@@ -248,7 +248,7 @@ static int
 spdk_nvme_map_prps(struct spdk_vhost_nvme_dev *nvme, struct spdk_nvme_cmd *cmd,
 		   struct spdk_vhost_nvme_task *task, uint32_t len)
 {
-	struct spdk_vhost_session *vsession = &nvme->vdev.session;
+	struct spdk_vhost_session *vsession = nvme->vdev.session;
 	uint64_t prp1, prp2;
 	void *vva;
 	uint32_t i;
@@ -699,7 +699,7 @@ static int
 vhost_nvme_doorbell_buffer_config(struct spdk_vhost_nvme_dev *nvme,
 				  struct spdk_nvme_cmd *cmd, struct spdk_nvme_cpl *cpl)
 {
-	struct spdk_vhost_session *vsession = &nvme->vdev.session;
+	struct spdk_vhost_session *vsession = nvme->vdev.session;
 	uint64_t dbs_dma_addr, eis_dma_addr;
 
 	dbs_dma_addr = cmd->dptr.prp.prp1;
@@ -765,7 +765,7 @@ vhost_nvme_create_io_sq(struct spdk_vhost_nvme_dev *nvme,
 	sq->size = qsize + 1;
 	sq->sq_head = sq->sq_tail = 0;
 	requested_len = sizeof(struct spdk_nvme_cmd) * sq->size;
-	sq->sq_cmd = spdk_vhost_gpa_to_vva(&nvme->vdev.session, dma_addr, requested_len);
+	sq->sq_cmd = spdk_vhost_gpa_to_vva(nvme->vdev.session, dma_addr, requested_len);
 	if (!sq->sq_cmd) {
 		return -1;
 	}
@@ -848,7 +848,7 @@ vhost_nvme_create_io_cq(struct spdk_vhost_nvme_dev *nvme,
 	cq->guest_signaled_cq_head = 0;
 	cq->need_signaled_cnt = 0;
 	requested_len = sizeof(struct spdk_nvme_cpl) * cq->size;
-	cq->cq_cqe = spdk_vhost_gpa_to_vva(&nvme->vdev.session, dma_addr, requested_len);
+	cq->cq_cqe = spdk_vhost_gpa_to_vva(nvme->vdev.session, dma_addr, requested_len);
 	if (!cq->cq_cqe) {
 		return -1;
 	}
@@ -893,7 +893,7 @@ spdk_vhost_nvme_get_by_name(int vid)
 	struct spdk_vhost_nvme_dev *nvme;
 
 	TAILQ_FOREACH(nvme, &g_nvme_ctrlrs, tailq) {
-		if (nvme->vdev.session.vid == vid) {
+		if (nvme->vdev.session != NULL && nvme->vdev.session->vid == vid) {
 			return nvme;
 		}
 	}
@@ -1084,7 +1084,7 @@ spdk_vhost_nvme_start_device(struct spdk_vhost_dev *vdev, void *event_ctx)
 		return -1;
 	}
 
-	SPDK_NOTICELOG("Start Device %u, Path %s, lcore %d\n", vdev->session.vid,
+	SPDK_NOTICELOG("Start Device %u, Path %s, lcore %d\n", vdev->session->vid,
 		       vdev->path, vdev->lcore);
 
 	for (i = 0; i < nvme->num_ns; i++) {
@@ -1171,7 +1171,7 @@ spdk_vhost_nvme_stop_device(struct spdk_vhost_dev *vdev, void *event_ctx)
 	}
 
 	free_task_pool(nvme);
-	SPDK_NOTICELOG("Stopping Device %u, Path %s\n", vdev->session.vid, vdev->path);
+	SPDK_NOTICELOG("Stopping Device %u, Path %s\n", vdev->session->vid, vdev->path);
 
 	nvme->destroy_ctx.event_ctx = event_ctx;
 	spdk_poller_unregister(&nvme->requestq_poller);
diff --git a/lib/vhost/vhost_scsi.c b/lib/vhost/vhost_scsi.c
index 2cd9f42dc..e421605ca 100644
--- a/lib/vhost/vhost_scsi.c
+++ b/lib/vhost/vhost_scsi.c
@@ -134,7 +134,7 @@ static void
 spdk_vhost_scsi_task_free_cb(struct spdk_scsi_task *scsi_task)
 {
 	struct spdk_vhost_scsi_task *task = SPDK_CONTAINEROF(scsi_task, struct spdk_vhost_scsi_task, scsi);
-	struct spdk_vhost_session *vsession = &task->svdev->vdev.session;
+	struct spdk_vhost_session *vsession = task->svdev->vdev.session;
 
 	assert(vsession->task_cnt > 0);
 	vsession->task_cnt--;
@@ -170,7 +170,7 @@ static void
 eventq_enqueue(struct spdk_vhost_scsi_dev *svdev, unsigned scsi_dev_num, uint32_t event,
 	       uint32_t reason)
 {
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 	struct spdk_vhost_virtqueue *vq;
 	struct vring_desc *desc, *desc_table;
 	struct virtio_scsi_event *desc_ev;
@@ -223,7 +223,7 @@ out:
 static void
 submit_completion(struct spdk_vhost_scsi_task *task)
 {
-	struct spdk_vhost_session *vsession = &task->svdev->vdev.session;
+	struct spdk_vhost_session *vsession = task->svdev->vdev.session;
 
 	spdk_vhost_vq_used_ring_enqueue(vsession, task->vq, task->req_idx,
 					task->used_len);
@@ -280,7 +280,7 @@ mgmt_task_submit(struct spdk_vhost_scsi_task *task, enum spdk_scsi_task_func fun
 static void
 invalid_request(struct spdk_vhost_scsi_task *task)
 {
-	struct spdk_vhost_session *vsession = &task->svdev->vdev.session;
+	struct spdk_vhost_session *vsession = task->svdev->vdev.session;
 
 	spdk_vhost_vq_used_ring_enqueue(vsession, task->vq, task->req_idx,
 					task->used_len);
@@ -321,7 +321,7 @@ static void
 process_ctrl_request(struct spdk_vhost_scsi_task *task)
 {
 	struct spdk_vhost_dev *vdev = &task->svdev->vdev;
-	struct spdk_vhost_session *vsession = &vdev->session;
+	struct spdk_vhost_session *vsession = vdev->session;
 	struct vring_desc *desc, *desc_table;
 	struct virtio_scsi_ctrl_tmf_req *ctrl_req;
 	struct virtio_scsi_ctrl_an_resp *an_resp;
@@ -423,7 +423,7 @@ task_data_setup(struct spdk_vhost_scsi_task *task,
 		struct virtio_scsi_cmd_req **req)
 {
 	struct spdk_vhost_dev *vdev = &task->svdev->vdev;
-	struct spdk_vhost_session *vsession = &vdev->session;
+	struct spdk_vhost_session *vsession = vdev->session;
 	struct vring_desc *desc, *desc_table;
 	struct iovec *iovs = task->iovs;
 	uint16_t iovcnt = 0;
@@ -586,7 +586,7 @@ process_request(struct spdk_vhost_scsi_task *task)
 static void
 process_controlq(struct spdk_vhost_scsi_dev *svdev, struct spdk_vhost_virtqueue *vq)
 {
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 	struct spdk_vhost_scsi_task *task;
 	uint16_t reqs[32];
 	uint16_t reqs_cnt, i;
@@ -619,7 +619,7 @@ process_controlq(struct spdk_vhost_scsi_dev *svdev, struct spdk_vhost_virtqueue
 static void
 process_requestq(struct spdk_vhost_scsi_dev *svdev, struct spdk_vhost_virtqueue *vq)
 {
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 	struct spdk_vhost_scsi_task *task;
 	uint16_t reqs[32];
 	uint16_t reqs_cnt, i;
@@ -673,7 +673,7 @@ static int
 vdev_mgmt_worker(void *arg)
 {
 	struct spdk_vhost_scsi_dev *svdev = arg;
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 
 	process_removed_devs(svdev);
 	spdk_vhost_vq_used_signal(vsession, &vsession->virtqueue[VIRTIO_SCSI_EVENTQ]);
@@ -688,7 +688,7 @@ static int
 vdev_worker(void *arg)
 {
 	struct spdk_vhost_scsi_dev *svdev = arg;
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 	uint32_t q_idx;
 
 	for (q_idx = VIRTIO_SCSI_REQUESTQ; q_idx < vsession->max_queues; q_idx++) {
@@ -793,7 +793,7 @@ spdk_vhost_scsi_lun_hotremove(const struct spdk_scsi_lun *lun, void *arg)
 	assert(lun != NULL);
 	assert(svdev != NULL);
 	if (svdev->vdev.lcore != -1 &&
-	    !spdk_vhost_dev_has_feature(&svdev->vdev.session, VIRTIO_SCSI_F_HOTPLUG)) {
+	    !spdk_vhost_dev_has_feature(svdev->vdev.session, VIRTIO_SCSI_F_HOTPLUG)) {
 		SPDK_WARNLOG("%s: hotremove is not enabled for this controller.\n", svdev->vdev.name);
 		return;
 	}
@@ -873,7 +873,7 @@ spdk_vhost_scsi_dev_add_tgt(struct spdk_vhost_dev *vdev, unsigned scsi_tgt_num,
 
 	spdk_scsi_dev_allocate_io_channels(svdev->scsi_dev[scsi_tgt_num]);
 
-	if (spdk_vhost_dev_has_feature(&vdev->session, VIRTIO_SCSI_F_HOTPLUG)) {
+	if (spdk_vhost_dev_has_feature(vdev->session, VIRTIO_SCSI_F_HOTPLUG)) {
 		eventq_enqueue(svdev, scsi_tgt_num, VIRTIO_SCSI_T_TRANSPORT_RESET,
 			       VIRTIO_SCSI_EVT_RESET_RESCAN);
 	} else {
@@ -922,7 +922,7 @@ spdk_vhost_scsi_dev_remove_tgt(struct spdk_vhost_dev *vdev, unsigned scsi_tgt_nu
 		return rc;
 	}
 
-	if (!spdk_vhost_dev_has_feature(&vdev->session, VIRTIO_SCSI_F_HOTPLUG)) {
+	if (!spdk_vhost_dev_has_feature(vdev->session, VIRTIO_SCSI_F_HOTPLUG)) {
 		SPDK_WARNLOG("%s: 'Target %u' is in use and hot-detach is not enabled for this controller.\n",
 			     svdev->vdev.name, scsi_tgt_num);
 		return -ENOTSUP;
@@ -1015,7 +1015,7 @@ spdk_vhost_scsi_controller_construct(void)
 static void
 free_task_pool(struct spdk_vhost_scsi_dev *svdev)
 {
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 	struct spdk_vhost_virtqueue *vq;
 	uint16_t i;
 
@@ -1033,7 +1033,7 @@ free_task_pool(struct spdk_vhost_scsi_dev *svdev)
 static int
 alloc_task_pool(struct spdk_vhost_scsi_dev *svdev)
 {
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 	struct spdk_vhost_virtqueue *vq;
 	struct spdk_vhost_scsi_task *task;
 	uint32_t task_cnt;
@@ -1082,7 +1082,7 @@ static int
 spdk_vhost_scsi_start(struct spdk_vhost_dev *vdev, void *event_ctx)
 {
 	struct spdk_vhost_scsi_dev *svdev;
-	struct spdk_vhost_session *vsession = &vdev->session;
+	struct spdk_vhost_session *vsession = vdev->session;
 	uint32_t i;
 	int rc;
 
@@ -1132,7 +1132,7 @@ static int
 destroy_device_poller_cb(void *arg)
 {
 	struct spdk_vhost_scsi_dev *svdev = arg;
-	struct spdk_vhost_session *vsession = &svdev->vdev.session;
+	struct spdk_vhost_session *vsession = svdev->vdev.session;
 	uint32_t i;
 
 	if (vsession->task_cnt > 0) {
diff --git a/test/unit/lib/vhost/vhost.c/vhost_ut.c b/test/unit/lib/vhost/vhost.c/vhost_ut.c
index f7888865d..12f622e9f 100644
--- a/test/unit/lib/vhost/vhost.c/vhost_ut.c
+++ b/test/unit/lib/vhost/vhost.c/vhost_ut.c
@@ -152,6 +152,7 @@ static void
 start_vdev(struct spdk_vhost_dev *vdev)
 {
 	struct rte_vhost_memory *mem;
+	int rc;
 
 	mem = calloc(1, sizeof(*mem) + 2 * sizeof(struct rte_vhost_mem_region));
 	SPDK_CU_ASSERT_FATAL(mem != NULL);
@@ -164,22 +165,29 @@ start_vdev(struct spdk_vhost_dev *vdev)
 	mem->regions[1].host_user_addr = 0x2000000;
 
 	vdev->lcore = 0;
-	vdev->session.vid = 0;
-	vdev->session.mem = mem;
+	assert(vdev->session == NULL);
+	/* spdk_vhost_dev must be allocated on a cache line boundary. */
+	rc = posix_memalign((void **)&vdev->session, 64, sizeof(*vdev->session));
+	CU_ASSERT(rc == 0);
+	SPDK_CU_ASSERT_FATAL(vdev->session != NULL);
+	vdev->session->vid = 0;
+	vdev->session->mem = mem;
 }
 
 static void
 stop_vdev(struct spdk_vhost_dev *vdev)
 {
-	free(vdev->session.mem);
-	vdev->session.mem = NULL;
-	vdev->session.vid = -1;
+	free(vdev->session->mem);
+	free(vdev->session);
+	vdev->session = NULL;
 }
 
 static void
 cleanup_vdev(struct spdk_vhost_dev *vdev)
 {
-	stop_vdev(vdev);
+	if (vdev->session) {
+		stop_vdev(vdev);
+	}
 	spdk_vhost_dev_unregister(vdev);
 	free(vdev);
 }
@@ -198,7 +206,7 @@ desc_to_iov_test(void)
 	SPDK_CU_ASSERT_FATAL(rc == 0 && vdev);
 	start_vdev(vdev);
 
-	vsession = &vdev->session;
+	vsession = vdev->session;
 
 	/* Test simple case where iov falls fully within a 2MB page. */
 	desc.addr = 0x110000;
@@ -310,12 +318,13 @@ session_find_by_vid_test(void)
 
 	rc = alloc_vdev(&vdev, "vdev_name_0", "0x1");
 	SPDK_CU_ASSERT_FATAL(rc == 0 && vdev);
+	start_vdev(vdev);
 
-	tmp = spdk_vhost_session_find_by_vid(vdev->session.vid);
-	CU_ASSERT(tmp == &vdev->session);
+	tmp = spdk_vhost_session_find_by_vid(vdev->session->vid);
+	CU_ASSERT(tmp == vdev->session);
 
 	/* Search for a device with incorrect vid */
-	tmp = spdk_vhost_session_find_by_vid(vdev->session.vid + 0xFF);
+	tmp = spdk_vhost_session_find_by_vid(vdev->session->vid + 0xFF);
 	CU_ASSERT(tmp == NULL);
 
 	cleanup_vdev(vdev);