diff --git a/include/spdk/vhost.h b/include/spdk/vhost.h
index aa4944bf8..990b2f0e6 100644
--- a/include/spdk/vhost.h
+++ b/include/spdk/vhost.h
@@ -312,14 +312,16 @@ int spdk_vhost_scsi_dev_remove_tgt(struct spdk_vhost_dev *vdev, unsigned scsi_tg
  * is allowed but not required. The mask itself can be constructed as:
  * ((1 << cpu0) | (1 << cpu1) | ... | (1 << cpuN)).
  * \param dev_name bdev name to associate with this vhost device
- * \param readonly if set, all writes to the device will fail with
+ * \param params JSON value object containing variables:
+ * readonly if set, all writes to the device will fail with
  * \c VIRTIO_BLK_S_IOERR error code.
- * \param packed_ring this controller supports packed ring if set.
+ * packed_ring this controller supports packed ring if set.
+ * packed_ring_recovery
  *
  * \return 0 on success, negative errno on error.
  */
 int spdk_vhost_blk_construct(const char *name, const char *cpumask, const char *dev_name,
-			     bool readonly, bool packed_ring);
+			     const struct spdk_json_val *params);
 
 /**
  * Remove a vhost device. The device must not have any open connections on it's socket.
diff --git a/lib/vhost/vhost_blk.c b/lib/vhost/vhost_blk.c
index 362604286..76bea817c 100644
--- a/lib/vhost/vhost_blk.c
+++ b/lib/vhost/vhost_blk.c
@@ -107,6 +107,18 @@ struct spdk_vhost_blk_session {
 	struct spdk_poller *stop_poller;
 };
 
+struct rpc_vhost_blk {
+	bool readonly;
+	bool packed_ring;
+	bool packed_ring_recovery;
+};
+
+static const struct spdk_json_object_decoder rpc_construct_vhost_blk[] = {
+	{"readonly", offsetof(struct rpc_vhost_blk, readonly), spdk_json_decode_bool, true},
+	{"packed_ring", offsetof(struct rpc_vhost_blk, packed_ring), spdk_json_decode_bool, true},
+	{"packed_ring_recovery", offsetof(struct rpc_vhost_blk, packed_ring_recovery), spdk_json_decode_bool, true},
+};
+
 /* forward declaration */
 static const struct spdk_vhost_dev_backend vhost_blk_device_backend;
 
@@ -1534,8 +1546,9 @@ static const struct spdk_vhost_dev_backend vhost_blk_device_backend = {
 
 int
 spdk_vhost_blk_construct(const char *name, const char *cpumask, const char *dev_name,
-			 bool readonly, bool packed_ring)
+			 const struct spdk_json_val *params)
 {
+	struct rpc_vhost_blk req = {0};
 	struct spdk_vhost_blk_dev *bvdev = NULL;
 	struct spdk_vhost_dev *vdev;
 	struct spdk_bdev *bdev;
@@ -1543,6 +1556,15 @@ spdk_vhost_blk_construct(const char *name, const char *cpumask, const char *dev_
 
 	spdk_vhost_lock();
 
+	if (spdk_json_decode_object_relaxed(params, rpc_construct_vhost_blk,
+					    SPDK_COUNTOF(rpc_construct_vhost_blk),
+					    &req)) {
+		SPDK_DEBUGLOG(vhost_blk, "spdk_json_decode_object failed\n");
+		ret = -EINVAL;
+		goto out;
+	}
+	g_packed_ring_recovery = req.packed_ring_recovery;
+
 	bvdev = calloc(1, sizeof(*bvdev));
 	if (bvdev == NULL) {
 		ret = -ENOMEM;
@@ -1562,7 +1584,7 @@ spdk_vhost_blk_construct(const char *name, const char *cpumask, const char *dev_
 	vdev->disabled_features = SPDK_VHOST_BLK_DISABLED_FEATURES;
 	vdev->protocol_features = SPDK_VHOST_BLK_PROTOCOL_FEATURES;
 
-	vdev->virtio_features |= (uint64_t)packed_ring << VIRTIO_F_RING_PACKED;
+	vdev->virtio_features |= (uint64_t)req.packed_ring << VIRTIO_F_RING_PACKED;
 
 	if (spdk_bdev_io_type_supported(bdev, SPDK_BDEV_IO_TYPE_UNMAP)) {
 		vdev->virtio_features |= (1ULL << VIRTIO_BLK_F_DISCARD);
@@ -1570,7 +1592,7 @@ spdk_vhost_blk_construct(const char *name, const char *cpumask, const char *dev_
 	if (spdk_bdev_io_type_supported(bdev, SPDK_BDEV_IO_TYPE_WRITE_ZEROES)) {
 		vdev->virtio_features |= (1ULL << VIRTIO_BLK_F_WRITE_ZEROES);
 	}
-	if (readonly) {
+	if (req.readonly) {
 		vdev->virtio_features |= (1ULL << VIRTIO_BLK_F_RO);
 	}
 	if (spdk_bdev_io_type_supported(bdev, SPDK_BDEV_IO_TYPE_FLUSH)) {
@@ -1591,7 +1613,7 @@ spdk_vhost_blk_construct(const char *name, const char *cpumask, const char *dev_
 	bvdev->dummy_io_channel = spdk_bdev_get_io_channel(bvdev->bdev_desc);
 
 	bvdev->bdev = bdev;
-	bvdev->readonly = readonly;
+	bvdev->readonly = req.readonly;
 	ret = vhost_dev_register(vdev, name, cpumask, &vhost_blk_device_backend);
 	if (ret != 0) {
 		spdk_put_io_channel(bvdev->dummy_io_channel);
diff --git a/lib/vhost/vhost_rpc.c b/lib/vhost/vhost_rpc.c
index b1555f2fb..f5e3fc13a 100644
--- a/lib/vhost/vhost_rpc.c
+++ b/lib/vhost/vhost_rpc.c
@@ -235,18 +235,12 @@ struct rpc_vhost_blk_ctrlr {
 	char *ctrlr;
 	char *dev_name;
 	char *cpumask;
-	bool readonly;
-	bool packed_ring;
-	bool packed_ring_recovery;
 };
 
 static const struct spdk_json_object_decoder rpc_construct_vhost_blk_ctrlr[] = {
 	{"ctrlr", offsetof(struct rpc_vhost_blk_ctrlr, ctrlr), spdk_json_decode_string },
 	{"dev_name", offsetof(struct rpc_vhost_blk_ctrlr, dev_name), spdk_json_decode_string },
 	{"cpumask", offsetof(struct rpc_vhost_blk_ctrlr, cpumask), spdk_json_decode_string, true},
-	{"readonly", offsetof(struct rpc_vhost_blk_ctrlr, readonly), spdk_json_decode_bool, true},
-	{"packed_ring", offsetof(struct rpc_vhost_blk_ctrlr, packed_ring), spdk_json_decode_bool, true},
-	{"packed_ring_recovery", offsetof(struct rpc_vhost_blk_ctrlr, packed_ring_recovery), spdk_json_decode_bool, true},
 };
 
 static void
@@ -264,18 +258,15 @@ rpc_vhost_create_blk_controller(struct spdk_jsonrpc_request *request,
 	struct rpc_vhost_blk_ctrlr req = {0};
 	int rc;
 
-	if (spdk_json_decode_object(params, rpc_construct_vhost_blk_ctrlr,
-				    SPDK_COUNTOF(rpc_construct_vhost_blk_ctrlr),
-				    &req)) {
+	if (spdk_json_decode_object_relaxed(params, rpc_construct_vhost_blk_ctrlr,
+					    SPDK_COUNTOF(rpc_construct_vhost_blk_ctrlr),
+					    &req)) {
 		SPDK_DEBUGLOG(vhost_rpc, "spdk_json_decode_object failed\n");
 		rc = -EINVAL;
 		goto invalid;
 	}
 
-	g_packed_ring_recovery = req.packed_ring_recovery;
-
-	rc = spdk_vhost_blk_construct(req.ctrlr, req.cpumask, req.dev_name,
-				      req.readonly, req.packed_ring);
+	rc = spdk_vhost_blk_construct(req.ctrlr, req.cpumask, req.dev_name, params);
 	if (rc < 0) {
 		goto invalid;
 	}