diff --git a/src/runtime-rs/config/configuration-cloud-hypervisor.toml.in b/src/runtime-rs/config/configuration-cloud-hypervisor.toml.in
index 726a2b33ad..c10d72e465 100644
--- a/src/runtime-rs/config/configuration-cloud-hypervisor.toml.in
+++ b/src/runtime-rs/config/configuration-cloud-hypervisor.toml.in
@@ -172,6 +172,11 @@ default_bridges = @DEFBRIDGES@
 # rootfs is backed by a block device.
 block_device_driver = "virtio-blk-pci"
 
+# Specifies cache-related options for block devices.
+# Denotes whether use of O_DIRECT (bypass the host page cache) is enabled.
+# Default false
+#block_device_cache_direct = true
+
 # Enable huge pages for VM RAM, default false
 # Enabling this will result in the VM memory
 # being allocated using huge pages.
diff --git a/src/runtime-rs/config/configuration-dragonball.toml.in b/src/runtime-rs/config/configuration-dragonball.toml.in
index e2dc7ae856..5d1b8e408f 100644
--- a/src/runtime-rs/config/configuration-dragonball.toml.in
+++ b/src/runtime-rs/config/configuration-dragonball.toml.in
@@ -204,6 +204,11 @@ virtio_fs_extra_args = @DEFVIRTIOFSEXTRAARGS@
 #    Metadata, data, and pathname lookup are cached in guest and never expire.
 virtio_fs_cache = "@DEFVIRTIOFSCACHE@"
 
+# Specifies cache-related options for block devices.
+# Denotes whether use of O_DIRECT (bypass the host page cache) is enabled.
+# Default false
+#block_device_cache_direct = true
+
 # Enable huge pages for VM RAM, default false
 # Enabling this will result in the VM memory
 # being allocated using huge pages.