diff --git a/runc/src/common.rs b/runc/src/common.rs
index fa1011f7..b3fe0bc6 100644
--- a/runc/src/common.rs
+++ b/runc/src/common.rs
@@ -42,7 +42,6 @@ use runc::{
 pub const INIT_PID_FILE: &str = "init.pid";
 
 pub struct ProcessIO {
-    pub uri: Option<String>,
     pub io: Option<Arc<dyn Io>>,
     pub copy: bool,
 }
@@ -56,7 +55,6 @@ pub fn create_io(
     if stdio.is_null() {
         let nio = NullIo::new().map_err(io_error!(e, "new Null Io"))?;
         let pio = ProcessIO {
-            uri: None,
             io: Some(Arc::new(nio)),
             copy: false,
         };
@@ -64,20 +62,15 @@ pub fn create_io(
     }
     let stdout = stdio.stdout.as_str();
     let scheme_path = stdout.trim().split("://").collect::<Vec<&str>>();
-    let scheme: &str;
-    let uri: String;
-    if scheme_path.len() <= 1 {
+    let scheme = if scheme_path.len() <= 1 {
         // no scheme specified
         // default schema to fifo
-        uri = format!("fifo://{}", stdout);
-        scheme = "fifo"
+        "fifo"
     } else {
-        uri = stdout.to_string();
-        scheme = scheme_path[0];
-    }
+        scheme_path[0]
+    };
 
     let mut pio = ProcessIO {
-        uri: Some(uri),
         io: None,
         copy: false,
     };
diff --git a/runc/src/sandbox.rs b/runc/src/sandbox.rs
index a10a7172..e1032662 100644
--- a/runc/src/sandbox.rs
+++ b/runc/src/sandbox.rs
@@ -181,7 +181,7 @@ impl Sandboxer for RuncSandboxer {
             e
         })?;
 
-        sandbox.data.task_address = self.task_address.clone();
+        sandbox.data.task_address.clone_from(&self.task_address);
         sandbox.dump().await.map_err(|e| {
             kill(Pid::from_raw(sandbox_pid), Signal::SIGKILL).unwrap_or_default();
             e
diff --git a/shim/src/io.rs b/shim/src/io.rs
index e5f7f5f3..13d7545c 100644
--- a/shim/src/io.rs
+++ b/shim/src/io.rs
@@ -129,10 +129,8 @@ impl VsockIO {
         }
         Err(other!("timeout connect to port {}", self.port))
     }
-}
 
-impl ToString for VsockIO {
-    fn to_string(&self) -> String {
+    fn convert_to_string(&self) -> String {
         if self.sock_path.is_empty() {
             String::new()
         } else {
@@ -336,15 +334,15 @@ impl ContainerIoTransport for VSockTransport {
     }
 
     fn container_in(&self) -> String {
-        self.stdin.clone().unwrap_or_default().to_string()
+        self.stdin.clone().unwrap_or_default().convert_to_string()
     }
 
     fn container_out(&self) -> String {
-        self.stdout.clone().unwrap_or_default().to_string()
+        self.stdout.clone().unwrap_or_default().convert_to_string()
     }
 
     fn container_err(&self) -> String {
-        self.stderr.clone().unwrap_or_default().to_string()
+        self.stderr.clone().unwrap_or_default().convert_to_string()
     }
 
     async fn new_task_client(address: &str) -> Result<TaskClient> {
diff --git a/shim/src/task.rs b/shim/src/task.rs
index 8f07ebaf..c481b5fb 100644
--- a/shim/src/task.rs
+++ b/shim/src/task.rs
@@ -255,7 +255,7 @@ where
         req_new.stderr = shim_io.container_err();
 
         if !prepare_res.bundle.is_empty() {
-            req_new.bundle = prepare_res.bundle.clone();
+            req_new.bundle.clone_from(&prepare_res.bundle);
         }
 
         let res = self.task.create(ctx, req_new).await?;
diff --git a/vmm/sandbox/derive/src/lib.rs b/vmm/sandbox/derive/src/lib.rs
index c11ca719..1702d2f4 100644
--- a/vmm/sandbox/derive/src/lib.rs
+++ b/vmm/sandbox/derive/src/lib.rs
@@ -14,8 +14,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-#![allow(dead_code)]
-
 #[macro_use]
 extern crate quote;
 
diff --git a/vmm/sandbox/src/cloud_hypervisor/devices/device.rs b/vmm/sandbox/src/cloud_hypervisor/devices/device.rs
index fd297604..2554c587 100644
--- a/vmm/sandbox/src/cloud_hypervisor/devices/device.rs
+++ b/vmm/sandbox/src/cloud_hypervisor/devices/device.rs
@@ -26,7 +26,6 @@ pub struct PhysicalDevice {
 
 impl_device_no_bus!(PhysicalDevice);
 
-#[allow(dead_code)]
 impl PhysicalDevice {
     pub fn new(path: &str, id: &str) -> Self {
         Self {
diff --git a/vmm/sandbox/src/cloud_hypervisor/mod.rs b/vmm/sandbox/src/cloud_hypervisor/mod.rs
index a5f9b352..53ae16d9 100644
--- a/vmm/sandbox/src/cloud_hypervisor/mod.rs
+++ b/vmm/sandbox/src/cloud_hypervisor/mod.rs
@@ -98,7 +98,7 @@ impl CloudHypervisorVM {
         }
     }
 
-    pub fn add_device(&mut self, device: impl CloudHypervisorDevice + Sync + Send + 'static) {
+    pub fn add_device(&mut self, device: impl CloudHypervisorDevice + 'static) {
         self.devices.push(Box::new(device));
     }
 
diff --git a/vmm/sandbox/src/container/handler/mod.rs b/vmm/sandbox/src/container/handler/mod.rs
index 28a41c3f..576505ae 100644
--- a/vmm/sandbox/src/container/handler/mod.rs
+++ b/vmm/sandbox/src/container/handler/mod.rs
@@ -14,8 +14,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-use std::ptr::NonNull;
-
 use async_trait::async_trait;
 use containerd_sandbox::{error::Result, ContainerOption, Sandbox};
 use log::warn;
@@ -42,40 +40,6 @@ mod process;
 mod spec;
 mod storage;
 
-pub struct HandlerNode<S> {
-    pub handler: Box<dyn Handler<S> + Sync + Send>,
-    pub next: Option<NonNull<HandlerNode<S>>>,
-    pub prev: Option<NonNull<HandlerNode<S>>>,
-}
-
-unsafe impl<S> Sync for HandlerNode<S> {}
-
-unsafe impl<S> Send for HandlerNode<S> {}
-
-impl<S> HandlerNode<S>
-where
-    S: Sync + Send,
-{
-    #[allow(dead_code)]
-    pub fn new(handler: Box<dyn Handler<S> + Sync + Send>) -> Self {
-        Self {
-            handler,
-            next: None,
-            prev: None,
-        }
-    }
-
-    #[allow(dead_code)]
-    pub async fn handle(&self, sandbox: &mut S) -> Result<()> {
-        self.handler.handle(sandbox).await
-    }
-
-    #[allow(dead_code)]
-    pub async fn rollback(&self, sandbox: &mut S) -> Result<()> {
-        self.handler.rollback(sandbox).await
-    }
-}
-
 pub struct HandlerChain<S> {
     handlers: Vec<Box<dyn Handler<S> + Sync + Send>>,
 }
@@ -123,7 +87,6 @@ where
         Ok(())
     }
 
-    #[allow(dead_code)]
     pub async fn rollback(&self, sandbox: &mut S) -> Result<()> {
         for handler in self.handlers.iter().rev() {
             handler.rollback(sandbox).await.unwrap_or_else(|e| {
diff --git a/vmm/sandbox/src/container/handler/storage.rs b/vmm/sandbox/src/container/handler/storage.rs
index 2a77d982..a3276848 100644
--- a/vmm/sandbox/src/container/handler/storage.rs
+++ b/vmm/sandbox/src/container/handler/storage.rs
@@ -60,7 +60,7 @@ where
         for mut m in mounts {
             if let Some(storage) = sandbox.storages.iter().find(|x| x.is_for_mount(&m)) {
                 debug!("found storage {:?} for mount {:?}", storage, m);
-                m.source = storage.mount_point.clone();
+                m.source.clone_from(&storage.mount_point);
                 m.options = vec!["bind".to_string()];
                 if storage.need_guest_handle {
                     storages.push(storage);
diff --git a/vmm/sandbox/src/container/mod.rs b/vmm/sandbox/src/container/mod.rs
index f7040ab3..c565b136 100644
--- a/vmm/sandbox/src/container/mod.rs
+++ b/vmm/sandbox/src/container/mod.rs
@@ -22,12 +22,8 @@ use serde::{Deserialize, Serialize};
 
 mod handler;
 
-#[allow(dead_code)]
-const NULL_DEVICE: &str = "/dev/null";
-
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct KuasarContainer {
-    #[allow(dead_code)]
     pub(crate) id: String,
     pub(crate) data: ContainerData,
     pub(crate) io_devices: Vec<String>,
diff --git a/vmm/sandbox/src/device.rs b/vmm/sandbox/src/device.rs
index 38fd8a3e..8be20562 100644
--- a/vmm/sandbox/src/device.rs
+++ b/vmm/sandbox/src/device.rs
@@ -55,12 +55,9 @@ pub trait Device {
 #[allow(clippy::upper_case_acronyms)]
 pub enum BusType {
     PCI,
-    #[allow(dead_code)]
     PCIE,
-    #[allow(dead_code)]
     CCW,
     SCSI,
-    #[allow(dead_code)]
     MMIO,
     SERIAL,
     NULL,
@@ -99,7 +96,6 @@ impl Bus {
         None
     }
 
-    #[allow(dead_code)]
     pub fn attach<T: Device>(&mut self, device: &T) -> Result<usize> {
         for (index, s) in self.slots.iter_mut().enumerate() {
             if let SlotStatus::Empty = s.status {
@@ -110,7 +106,6 @@ impl Bus {
         Err(Error::ResourceExhausted("bus is full".to_string()))
     }
 
-    #[allow(dead_code)]
     pub fn device_slot(&self, id: &str) -> Option<usize> {
         for (index, s) in self.slots.iter().enumerate() {
             if index == 0 {
@@ -150,7 +145,6 @@ pub enum SlotStatus {
 pub enum Transport {
     Pci,
     Ccw,
-    #[allow(dead_code)]
     Mmio,
 }
 
diff --git a/vmm/sandbox/src/kata_config.rs b/vmm/sandbox/src/kata_config.rs
index 892ea652..d90ef3ab 100644
--- a/vmm/sandbox/src/kata_config.rs
+++ b/vmm/sandbox/src/kata_config.rs
@@ -250,7 +250,8 @@ impl Hypervisor {
         res.virtiofs_cache = self.virtio_fs_cache.to_string();
         res.virtiofs_cache_size = self.virtio_fs_cache_size;
         res.virtiofs_daemon_path = self.virtio_fs_daemon.to_string();
-        res.virtiofs_extra_args = self.virtio_fs_extra_args.clone();
+        res.virtiofs_extra_args
+            .clone_from(&self.virtio_fs_extra_args);
         res.virtio_9p_direct_io = self.virtio_9p_direct_io;
         if !self.virtio_9p_multidevs.is_empty() {
             res.virtio_9p_multidevs = self.virtio_9p_multidevs.to_string();
diff --git a/vmm/sandbox/src/network/address.rs b/vmm/sandbox/src/network/address.rs
index 4ecd313b..a223ee14 100644
--- a/vmm/sandbox/src/network/address.rs
+++ b/vmm/sandbox/src/network/address.rs
@@ -110,7 +110,7 @@ impl IpNet {
     }
 }
 
-#[derive(Default, Clone, Deserialize, Serialize)]
+#[derive(Default, Debug, Clone, Deserialize, Serialize)]
 #[serde(from = "String")]
 #[serde(into = "String")]
 pub struct MacAddress(pub(crate) Vec<u8>);
@@ -131,19 +131,13 @@ impl From<MacAddress> for String {
     }
 }
 
-impl ToString for MacAddress {
-    fn to_string(&self) -> String {
+impl std::fmt::Display for MacAddress {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         let mut segs = vec![];
         for u in self.0.as_slice() {
             segs.push(format!("{:02x}", u));
         }
-        segs.join(":")
-    }
-}
-
-impl Debug for MacAddress {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", self.to_string())
+        write!(f, "{}", segs.join(":"))
     }
 }
 
diff --git a/vmm/sandbox/src/network/link.rs b/vmm/sandbox/src/network/link.rs
index c33cdad2..55be0a63 100644
--- a/vmm/sandbox/src/network/link.rs
+++ b/vmm/sandbox/src/network/link.rs
@@ -16,6 +16,7 @@ limitations under the License.
 
 use std::{
     ffi::CStr,
+    fmt::{Display, Formatter},
     os::unix::{
         fs::OpenOptionsExt,
         prelude::{AsRawFd, OwnedFd},
@@ -53,9 +54,7 @@ use crate::{
 
 const DEVICE_DRIVER_VFIO: &str = "vfio-pci";
 
-#[allow(dead_code)]
 const SIOCETHTOOL: u64 = 0x8946;
-#[allow(dead_code)]
 const ETHTOOL_GDRVINFO: u32 = 0x00000003;
 
 const TUNSETIFF: u64 = 0x400454ca;
@@ -64,14 +63,12 @@ const TUNSETPERSIST: u64 = 0x400454cb;
 ioctl_write_ptr_bad!(ioctl_tun_set_iff, TUNSETIFF, ifreq);
 ioctl_write_ptr_bad!(ioctl_tun_set_persist, TUNSETPERSIST, u64);
 
-#[allow(dead_code)]
 #[repr(C)]
 pub struct Ifreq {
     ifr_name: [u8; 16],
     ifr_data: *mut libc::c_void,
 }
 
-#[allow(dead_code)]
 #[repr(C)]
 pub struct EthtoolDrvInfo {
     cmd: u32,
@@ -115,9 +112,9 @@ impl Default for LinkType {
     }
 }
 
-impl ToString for LinkType {
-    fn to_string(&self) -> String {
-        match &self {
+impl Display for LinkType {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let s = match &self {
             LinkType::Unkonwn => "".to_string(),
             LinkType::Bridge => "bridge".to_string(),
             LinkType::Veth => "veth".to_string(),
@@ -133,7 +130,8 @@ impl ToString for LinkType {
             LinkType::Physical(_, _) => "physical".to_string(),
             LinkType::Tap => "tap".to_string(),
             LinkType::Loopback => "loopback".to_string(),
-        }
+        };
+        write!(f, "{}", s)
     }
 }
 
diff --git a/vmm/sandbox/src/network/mod.rs b/vmm/sandbox/src/network/mod.rs
index a34f030b..721f88ee 100644
--- a/vmm/sandbox/src/network/mod.rs
+++ b/vmm/sandbox/src/network/mod.rs
@@ -14,7 +14,11 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-use std::{fmt::Debug, os::unix::prelude::AsRawFd, path::Path};
+use std::{
+    fmt::{Debug, Display, Formatter},
+    os::unix::prelude::AsRawFd,
+    path::Path,
+};
 
 use anyhow::anyhow;
 use containerd_sandbox::error::Result;
@@ -220,25 +224,22 @@ pub async fn execute_in_netns(netns: &str, mut cmd: std::process::Command) -> Re
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum NetType {
     Tap,
-    #[allow(dead_code)]
     MacVtap,
-    #[allow(dead_code)]
     IpVtap,
-    #[allow(dead_code)]
     VethTap,
-    #[allow(dead_code)]
     VhostUser,
 }
 
-impl ToString for NetType {
-    fn to_string(&self) -> String {
-        match self {
+impl Display for NetType {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let s = match &self {
             NetType::Tap => "tap".to_string(),
             NetType::MacVtap => "tap".to_string(),
             NetType::IpVtap => "tap".to_string(),
             NetType::VethTap => "tap".to_string(),
             NetType::VhostUser => "vhost-user".to_string(),
-        }
+        };
+        write!(f, "{}", s)
     }
 }
 
diff --git a/vmm/sandbox/src/network/netlink.rs b/vmm/sandbox/src/network/netlink.rs
index 0b517114..04dce2a3 100644
--- a/vmm/sandbox/src/network/netlink.rs
+++ b/vmm/sandbox/src/network/netlink.rs
@@ -19,9 +19,7 @@ use netlink_packet_core::{NetlinkMessage, NLM_F_ACK, NLM_F_CREATE, NLM_F_EXCL, N
 use netlink_packet_route::{RtnlMessage, TcMessage};
 use rtnetlink::{try_nl, Error, Handle};
 
-#[allow(dead_code)]
 const HANDLE_INGRESS: u32 = 0xfffffff1;
-#[allow(dead_code)]
 const HANDLE_TC_FILTER: u32 = 0xffff0000;
 
 pub struct QDiscAddRequest {
@@ -65,7 +63,6 @@ impl QDiscAddRequest {
     }
 }
 
-#[allow(dead_code)]
 pub struct TrafficFilterSetRequest {
     handle: Handle,
     message: TcMessage,
diff --git a/vmm/sandbox/src/param.rs b/vmm/sandbox/src/param.rs
index efa93196..3932439f 100644
--- a/vmm/sandbox/src/param.rs
+++ b/vmm/sandbox/src/param.rs
@@ -56,7 +56,6 @@ impl Param {
         }
     }
 
-    #[allow(dead_code)]
     pub fn get(&self, key: &str) -> Option<String> {
         self.properties
             .iter()
@@ -126,7 +125,6 @@ impl ToCmdLineParams for BoolParam {
     }
 }
 
-#[allow(dead_code)]
 impl BoolParam {
     pub fn new(key: &str, value: bool) -> Self {
         Self(key.to_string(), value)
@@ -135,7 +133,6 @@ impl BoolParam {
 
 pub struct VecParam<T>(String, Vec<T>);
 
-#[allow(dead_code)]
 impl<T> VecParam<T> {
     pub fn new(key: &str, val: Vec<T>) -> Self {
         Self(key.to_string(), val)
diff --git a/vmm/sandbox/src/qemu/config.rs b/vmm/sandbox/src/qemu/config.rs
index fdcdb938..354b23b5 100644
--- a/vmm/sandbox/src/qemu/config.rs
+++ b/vmm/sandbox/src/qemu/config.rs
@@ -14,7 +14,11 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-use std::{collections::HashMap, os::unix::io::RawFd};
+use std::{
+    collections::HashMap,
+    fmt::{Display, Formatter},
+    os::unix::io::RawFd,
+};
 
 use containerd_sandbox::error::{Error, Result};
 #[cfg(target_arch = "x86_64")]
@@ -28,16 +32,8 @@ use crate::{
     vm::{BlockDriver, HypervisorCommonConfig, ShareFsType},
 };
 
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_Q35: &str = "q35";
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_PC: &str = "pc";
 pub(crate) const MACHINE_TYPE_MICROVM_PCI: &str = "microvm-pci";
 pub(crate) const MACHINE_TYPE_VIRT: &str = "virt";
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_PSERIES: &str = "pseries";
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_CCW_VIRTIO: &str = "s390-ccw-virtio";
 
 #[cfg(target_arch = "x86_64")]
 const DEFAULT_QEMU_PATH: &str = "/usr/bin/qemu-system-x86_64";
@@ -416,23 +412,21 @@ impl Default for Incoming {
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum MigrationType {
-    #[allow(dead_code)]
     FD(RawFd),
-    #[allow(dead_code)]
     Exec(String),
-    #[allow(dead_code)]
     Tcp(String),
     Defer,
 }
 
-impl ToString for MigrationType {
-    fn to_string(&self) -> String {
-        match self {
+impl Display for MigrationType {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let s = match &self {
             MigrationType::FD(fd) => format!("fd:{}", fd),
             MigrationType::Exec(cmd) => format!("exec:{}", cmd),
             MigrationType::Tcp(endpoint) => format!("tcp:{}", endpoint),
             MigrationType::Defer => "defer".to_string(),
-        }
+        };
+        write!(f, "{}", s)
     }
 }
 
diff --git a/vmm/sandbox/src/qemu/devices/block.rs b/vmm/sandbox/src/qemu/devices/block.rs
index 9e72b144..829b8116 100644
--- a/vmm/sandbox/src/qemu/devices/block.rs
+++ b/vmm/sandbox/src/qemu/devices/block.rs
@@ -19,7 +19,7 @@ use containerd_sandbox::error::Result;
 use log::{debug, error};
 use qapi::{
     qmp::{
-        blockdev_add, blockdev_del, device_add, device_del, BlockdevOptions, BlockdevOptionsBase,
+        blockdev_add, blockdev_del, device_add, BlockdevOptions, BlockdevOptionsBase,
         BlockdevOptionsFile,
     },
     Dictionary,
@@ -199,13 +199,6 @@ impl VirtioBlockDevice {
         }
     }
 
-    #[allow(dead_code)]
-    fn to_device_del(&self) -> device_del {
-        device_del {
-            id: format!("virtio-{}", self.id()),
-        }
-    }
-
     fn to_blockdev_del(&self) -> blockdev_del {
         blockdev_del {
             node_name: self.id.to_string(),
diff --git a/vmm/sandbox/src/qemu/devices/char.rs b/vmm/sandbox/src/qemu/devices/char.rs
index 57c10089..b266f193 100644
--- a/vmm/sandbox/src/qemu/devices/char.rs
+++ b/vmm/sandbox/src/qemu/devices/char.rs
@@ -19,10 +19,7 @@ use async_trait::async_trait;
 use containerd_sandbox::error::Result;
 use log::{debug, error};
 use qapi::{
-    qmp::{
-        chardev_add, chardev_remove, device_add, device_del, ChardevBackend, ChardevCommon,
-        ChardevHostdev,
-    },
+    qmp::{chardev_add, chardev_remove, device_add, ChardevBackend, ChardevCommon, ChardevHostdev},
     Dictionary,
 };
 use sandbox_derive::CmdLineParams;
@@ -209,11 +206,4 @@ impl CharDevice {
             id: self.chardev_id.to_string(),
         }
     }
-
-    #[allow(dead_code)]
-    fn to_device_del(&self) -> device_del {
-        device_del {
-            id: self.id.to_string(),
-        }
-    }
 }
diff --git a/vmm/sandbox/src/qemu/devices/serial.rs b/vmm/sandbox/src/qemu/devices/serial.rs
index 01d20892..2a47f664 100644
--- a/vmm/sandbox/src/qemu/devices/serial.rs
+++ b/vmm/sandbox/src/qemu/devices/serial.rs
@@ -31,9 +31,6 @@ pub struct SerialBridge {
     pub romfile: Option<String>,
     #[property(key = "max_ports")]
     pub max_ports: Option<i32>,
-    #[property(ignore)]
-    pub transport: Transport,
-
     #[property(ignore)]
     pub(crate) bus: Bus,
 }
@@ -46,7 +43,6 @@ impl SerialBridge {
             disable_modern: transport.disable_modern(false),
             romfile: None,
             max_ports: None,
-            transport,
             bus: Bus {
                 r#type: BusType::SERIAL,
                 id: id.to_string(),
diff --git a/vmm/sandbox/src/qemu/devices/vhost_user.rs b/vmm/sandbox/src/qemu/devices/vhost_user.rs
index 27baa03a..0e8ffedd 100644
--- a/vmm/sandbox/src/qemu/devices/vhost_user.rs
+++ b/vmm/sandbox/src/qemu/devices/vhost_user.rs
@@ -14,22 +14,21 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+use std::fmt::{Display, Formatter};
+
 use sandbox_derive::CmdLineParams;
 
 #[derive(Debug, Clone)]
 pub enum VhostUserType {
     VhostUserNet(String),
-    // TODO: support virtiofs
-    #[allow(dead_code)]
-    VhostUserFS(String),
 }
 
-impl ToString for VhostUserType {
-    fn to_string(&self) -> String {
-        match &self {
+impl Display for VhostUserType {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let s = match &self {
             VhostUserType::VhostUserNet(r#type) => r#type.to_string(),
-            VhostUserType::VhostUserFS(r#type) => r#type.to_string(),
-        }
+        };
+        write!(f, "{}", s)
     }
 }
 
@@ -76,9 +75,6 @@ impl VhostUserDevice {
             VhostUserType::VhostUserNet(_) => {
                 format!("{}-{}", "net", id)
             }
-            VhostUserType::VhostUserFS(_) => {
-                format!("{}-{}", "fs", id)
-            }
         };
         Self {
             id: id.to_string(),
diff --git a/vmm/sandbox/src/qemu/qmp_client.rs b/vmm/sandbox/src/qemu/qmp_client.rs
index d2eb3e17..ec3421bf 100644
--- a/vmm/sandbox/src/qemu/qmp_client.rs
+++ b/vmm/sandbox/src/qemu/qmp_client.rs
@@ -31,14 +31,11 @@ use tokio::{
         oneshot::{channel, Sender},
         Mutex,
     },
-    task::JoinHandle,
 };
 
 pub struct QmpClient {
     qmp: QapiService<QmpStreamTokio<WriteHalf<UnixStream>>>,
     watchers: Arc<Mutex<Vec<QmpEventWatcher>>>,
-    #[allow(dead_code)]
-    handle: JoinHandle<()>,
 }
 
 pub struct QmpEventWatcher {
@@ -54,7 +51,7 @@ impl QmpClient {
         let event_watchers = Arc::new(Mutex::new(Vec::<QmpEventWatcher>::new()));
 
         let w_clone = event_watchers.clone();
-        let handle = tokio::spawn(async move {
+        tokio::spawn(async move {
             while let Some(Ok(event)) = events.next().await {
                 let mut ws = w_clone.lock().await;
                 let mut retained = vec![];
@@ -76,7 +73,6 @@ impl QmpClient {
         let client = Self {
             qmp: service,
             watchers: event_watchers,
-            handle,
         };
         Ok(client)
     }
diff --git a/vmm/sandbox/src/sandbox.rs b/vmm/sandbox/src/sandbox.rs
index e887f9b3..41c5af30 100644
--- a/vmm/sandbox/src/sandbox.rs
+++ b/vmm/sandbox/src/sandbox.rs
@@ -686,10 +686,6 @@ pub struct StaticDeviceSpec {
     pub(crate) _host_path: Vec<String>,
     #[serde(default)]
     pub(crate) _bdf: Vec<String>,
-    #[allow(dead_code)]
-    #[deprecated]
-    #[serde(default)]
-    pub(crate) gpu_group_id: i32,
 }
 
 fn monitor<V: VM + 'static>(sandbox_mutex: Arc<Mutex<KuasarSandbox<V>>>) {
diff --git a/vmm/sandbox/src/storage/mod.rs b/vmm/sandbox/src/storage/mod.rs
index 83915b10..566b3829 100644
--- a/vmm/sandbox/src/storage/mod.rs
+++ b/vmm/sandbox/src/storage/mod.rs
@@ -317,8 +317,6 @@ where
 }
 
 pub struct MountInfo {
-    pub device: String,
-    pub mount_point: String,
     pub fs_type: String,
     pub options: Vec<String>,
 }
diff --git a/vmm/sandbox/src/storage/mount.rs b/vmm/sandbox/src/storage/mount.rs
index ee0cf5fd..cd959709 100644
--- a/vmm/sandbox/src/storage/mount.rs
+++ b/vmm/sandbox/src/storage/mount.rs
@@ -45,15 +45,9 @@ pub async fn get_mount_info(mount_point: &str) -> Result<Option<MountInfo>> {
         // format: "/dev/sdc /mnt ext4 rw,relatime,stripe=64 0 0"
         let mp = fields[1].to_string();
         if mp == mount_point {
-            let device = fields[0].to_string();
             let fs_type = fields[2].to_string();
             let options = fields[3].split(',').map(|x| x.to_string()).collect();
-            return Ok(Some(MountInfo {
-                device,
-                mount_point: mp,
-                fs_type,
-                options,
-            }));
+            return Ok(Some(MountInfo { fs_type, options }));
         }
     }
     Ok(None)
diff --git a/vmm/sandbox/src/stratovirt/config.rs b/vmm/sandbox/src/stratovirt/config.rs
index 4a438b2a..a4a25717 100644
--- a/vmm/sandbox/src/stratovirt/config.rs
+++ b/vmm/sandbox/src/stratovirt/config.rs
@@ -24,18 +24,8 @@ use crate::{
     stratovirt::virtiofs::DEFAULT_VHOST_USER_FS_BIN_PATH, vm::HypervisorCommonConfig,
 };
 
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_Q35: &str = "q35";
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_PC: &str = "pc";
-#[allow(dead_code)]
 pub(crate) const MACHINE_TYPE_VIRT: &str = "virt";
-#[allow(dead_code)]
 pub(crate) const MACHINE_TYPE_MICROVM: &str = "microvm";
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_PSERIES: &str = "pseries";
-#[allow(dead_code)]
-pub(crate) const MACHINE_TYPE_CCW_VIRTIO: &str = "s390-ccw-virtio";
 
 const DEFAULT_STRATOVIRT_PATH: &str = "/usr/bin/stratovirt";
 const DEFAULT_KERNEL_PARAMS: &str = "console=hvc0 console=hvc1 iommu=off panic=1 pcie_ports=native";
diff --git a/vmm/sandbox/src/stratovirt/devices/block.rs b/vmm/sandbox/src/stratovirt/devices/block.rs
index f1288d83..b3d9c038 100644
--- a/vmm/sandbox/src/stratovirt/devices/block.rs
+++ b/vmm/sandbox/src/stratovirt/devices/block.rs
@@ -19,7 +19,7 @@ use containerd_sandbox::error::Result;
 use log::{debug, error};
 use qapi::{
     qmp::{
-        blockdev_add, blockdev_del, device_add, device_del, BlockdevCacheOptions, BlockdevOptions,
+        blockdev_add, blockdev_del, device_add, BlockdevCacheOptions, BlockdevOptions,
         BlockdevOptionsBase, BlockdevOptionsFile, BlockdevOptionsGenericFormat, BlockdevOptionsRaw,
         BlockdevRef,
     },
@@ -33,7 +33,6 @@ use crate::{
     stratovirt::{devices::HotAttachable, qmp_client::QmpClient},
 };
 
-#[allow(dead_code)]
 pub const VIRTIO_BLK_DRIVER: &str = "virtio-blk";
 
 #[derive(CmdLineParams, Debug, Clone)]
@@ -61,7 +60,7 @@ pub struct VirtioBlockDevice {
 }
 
 impl_device_no_bus!(VirtioBlockDevice);
-impl_set_get_device_addr!(VirtioBlockDevice);
+impl_set_device_addr!(VirtioBlockDevice);
 
 impl VirtioBlockDevice {
     pub fn new(
@@ -174,13 +173,6 @@ impl VirtioBlockDevice {
         }
     }
 
-    #[allow(dead_code)]
-    fn to_device_del(&self) -> device_del {
-        device_del {
-            id: format!("virtio-{}", self.id()),
-        }
-    }
-
     fn to_blockdev_del(&self) -> blockdev_del {
         blockdev_del {
             node_name: self.id.to_string(),
@@ -222,7 +214,7 @@ mod tests {
 
         assert!(compare_json_strings(
             &blockdev_add_qmp_json_str,
-            expected_params_str
+            expected_params_str,
         ));
     }
 
@@ -246,7 +238,7 @@ mod tests {
         let expected_params_str = r#"{"driver":"virtio-blk-pci","id":"virtio-drive-0","bus":"pcie.1","addr":"0x0","drive":"drive-0"}"#;
         assert!(compare_json_strings(
             &device_add_qmp_json_str,
-            expected_params_str
+            expected_params_str,
         ));
     }
 
@@ -270,25 +262,4 @@ mod tests {
         let expected_params_str = r#"{"node-name":"drive-0"}"#;
         assert_eq!(expected_params_str, blockdev_del_qmp_json_str);
     }
-
-    #[test]
-    fn test_device_del_qmp_commands() {
-        let virtio_blk_device = VirtioBlockDevice::new(
-            VIRTIO_BLK_DRIVER,
-            "drive-0",
-            "",
-            Some("/dev/dm-8".to_string()),
-            Some(false),
-        );
-
-        let device_del_qmp_cmd = virtio_blk_device.to_device_del();
-        let device_del_qmp_json_str = serde_json::to_string(&device_del_qmp_cmd).unwrap();
-        println!(
-            "device_del qmp cmd json string: {}",
-            device_del_qmp_json_str
-        );
-
-        let expected_params_str = r#"{"id":"virtio-drive-0"}"#;
-        assert_eq!(expected_params_str, device_del_qmp_json_str);
-    }
 }
diff --git a/vmm/sandbox/src/stratovirt/devices/char.rs b/vmm/sandbox/src/stratovirt/devices/char.rs
index 075d7ba1..62704952 100644
--- a/vmm/sandbox/src/stratovirt/devices/char.rs
+++ b/vmm/sandbox/src/stratovirt/devices/char.rs
@@ -42,7 +42,7 @@ pub struct CharDevice {
 }
 
 impl_device_no_bus!(CharDevice);
-impl_set_get_device_addr!(CharDevice);
+impl_set_device_addr!(CharDevice);
 
 impl CharDevice {
     pub fn new(backend: &str, chardev_id: &str, path: &str) -> Self {
@@ -57,10 +57,9 @@ impl CharDevice {
     }
 }
 
+#[cfg(test)]
 mod tests {
-    #[allow(unused_imports)]
     use super::CharDevice;
-    #[allow(unused_imports)]
     use crate::param::ToCmdLineParams;
 
     #[test]
diff --git a/vmm/sandbox/src/stratovirt/devices/console.rs b/vmm/sandbox/src/stratovirt/devices/console.rs
index 126a2e1d..c2901680 100644
--- a/vmm/sandbox/src/stratovirt/devices/console.rs
+++ b/vmm/sandbox/src/stratovirt/devices/console.rs
@@ -30,7 +30,7 @@ pub struct VirtConsole {
 }
 
 impl_device_no_bus!(VirtConsole);
-impl_set_get_device_addr!(VirtConsole);
+impl_set_device_addr!(VirtConsole);
 
 impl VirtConsole {
     pub fn new(id: &str, chardev_id: &str) -> Self {
@@ -43,16 +43,15 @@ impl VirtConsole {
     }
 }
 
+#[cfg(test)]
 mod tests {
-    #[allow(unused_imports)]
     use super::VirtConsole;
-    #[allow(unused_imports)]
     use crate::{
         device::Transport,
         param::ToCmdLineParams,
         stratovirt::devices::{
-            char::CharDevice, device::GetAndSetDeviceAddr, serial::SerialDevice, DEFAULT_PCIE_BUS,
-            VIRTIO_SERIAL_CONSOLE_ADDR,
+            char::CharDevice, device::SetDeviceAddr, serial::SerialDevice,
+            tests::VIRTIO_SERIAL_CONSOLE_ADDR, DEFAULT_PCIE_BUS,
         },
     };
 
diff --git a/vmm/sandbox/src/stratovirt/devices/device.rs b/vmm/sandbox/src/stratovirt/devices/device.rs
index 6a22496f..bdd6b2d9 100644
--- a/vmm/sandbox/src/stratovirt/devices/device.rs
+++ b/vmm/sandbox/src/stratovirt/devices/device.rs
@@ -14,18 +14,13 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-pub trait GetAndSetDeviceAddr {
-    fn get_device_addr(&self) -> String;
+pub trait SetDeviceAddr {
     fn set_device_addr(&mut self, addr: usize);
 }
 
-macro_rules! impl_set_get_device_addr {
+macro_rules! impl_set_device_addr {
     ($ty:ty) => {
-        impl crate::stratovirt::devices::device::GetAndSetDeviceAddr for $ty {
-            fn get_device_addr(&self) -> String {
-                self.addr.clone()
-            }
-
+        impl crate::stratovirt::devices::device::SetDeviceAddr for $ty {
             fn set_device_addr(&mut self, addr: usize) {
                 self.addr = format!("{:#02x}", addr);
             }
diff --git a/vmm/sandbox/src/stratovirt/devices/mod.rs b/vmm/sandbox/src/stratovirt/devices/mod.rs
index 41f57167..168ad0f4 100644
--- a/vmm/sandbox/src/stratovirt/devices/mod.rs
+++ b/vmm/sandbox/src/stratovirt/devices/mod.rs
@@ -17,11 +17,11 @@ limitations under the License.
 use async_trait::async_trait;
 use containerd_sandbox::error::Result;
 
-use self::{device::GetAndSetDeviceAddr, pcie_rootbus::PcieRootBus};
+use self::pcie_rootbus::PcieRootBus;
 use crate::{
     device::{Bus, BusType, Device, Slot, SlotStatus},
     param::ToCmdLineParams,
-    stratovirt::qmp_client::QmpClient,
+    stratovirt::{devices::device::SetDeviceAddr, qmp_client::QmpClient},
 };
 
 #[macro_use]
@@ -47,20 +47,9 @@ pub(crate) const DEFAULT_SERIAL_DEVICE_ID: &str = "virtio-serial0";
 pub(crate) const DEFAULT_CONSOLE_DEVICE_ID: &str = "virtio-console0";
 pub(crate) const DEFAULT_CONSOLE_CHARDEV_ID: &str = "charconsole0";
 
-#[allow(dead_code)]
-pub(crate) const VIRTIO_RND_DEVICE_ADDR: usize = 1;
-#[allow(dead_code)]
-pub(crate) const VIRTIO_SERIAL_CONSOLE_ADDR: usize = 2;
-#[allow(dead_code)]
-pub(crate) const VHOST_VSOCK_ADDR: usize = 3;
-#[allow(dead_code)]
-pub(crate) const VHOST_USER_FS_ADDR: usize = 4;
-#[allow(dead_code)]
-pub(crate) const ROOTPORT_PCI_START_ADDR: usize = 5;
+pub trait StratoVirtDevice: Device + ToCmdLineParams + SetDeviceAddr {}
 
-pub trait StratoVirtDevice: Device + ToCmdLineParams + GetAndSetDeviceAddr {}
-
-impl<T> StratoVirtDevice for T where T: Device + ToCmdLineParams + GetAndSetDeviceAddr {}
+impl<T> StratoVirtDevice for T where T: Device + ToCmdLineParams + SetDeviceAddr {}
 
 #[async_trait]
 pub trait HotAttachable {
@@ -90,6 +79,12 @@ pub fn create_pcie_root_bus() -> Option<PcieRootBus> {
 
 #[cfg(test)]
 mod tests {
+    pub(crate) const VIRTIO_RND_DEVICE_ADDR: usize = 1;
+    pub(crate) const VIRTIO_SERIAL_CONSOLE_ADDR: usize = 2;
+    pub(crate) const VHOST_VSOCK_ADDR: usize = 3;
+    pub(crate) const VHOST_USER_FS_ADDR: usize = 4;
+    pub(crate) const ROOTPORT_PCI_START_ADDR: usize = 5;
+
     use super::create_pcie_root_bus;
     use crate::device::SlotStatus;
 
diff --git a/vmm/sandbox/src/stratovirt/devices/rng.rs b/vmm/sandbox/src/stratovirt/devices/rng.rs
index 3e9f9881..956cb128 100644
--- a/vmm/sandbox/src/stratovirt/devices/rng.rs
+++ b/vmm/sandbox/src/stratovirt/devices/rng.rs
@@ -45,7 +45,7 @@ pub struct VirtioRngDevice {
 }
 
 impl_device_no_bus!(VirtioRngDevice);
-impl_set_get_device_addr!(VirtioRngDevice);
+impl_set_device_addr!(VirtioRngDevice);
 
 impl VirtioRngDevice {
     pub fn new(id: &str, filename: &str, transport: Transport, bus: &str) -> Self {
@@ -70,7 +70,7 @@ mod tests {
         device::Transport,
         param::ToCmdLineParams,
         stratovirt::devices::{
-            device::GetAndSetDeviceAddr, DEFAULT_PCIE_BUS, VIRTIO_RND_DEVICE_ADDR,
+            device::SetDeviceAddr, tests::VIRTIO_RND_DEVICE_ADDR, DEFAULT_PCIE_BUS,
         },
     };
 
diff --git a/vmm/sandbox/src/stratovirt/devices/rootport.rs b/vmm/sandbox/src/stratovirt/devices/rootport.rs
index 9df8377b..19bc7581 100644
--- a/vmm/sandbox/src/stratovirt/devices/rootport.rs
+++ b/vmm/sandbox/src/stratovirt/devices/rootport.rs
@@ -54,7 +54,7 @@ impl RootPort {
 }
 
 impl_device_no_bus!(RootPort);
-impl_set_get_device_addr!(RootPort);
+impl_set_device_addr!(RootPort);
 
 #[derive(Debug, Clone, Default)]
 pub struct PCIERootPorts {
@@ -71,7 +71,7 @@ mod tests {
     use crate::{
         param::ToCmdLineParams,
         stratovirt::devices::{
-            device::GetAndSetDeviceAddr, DEFAULT_PCIE_BUS, ROOTPORT_PCI_START_ADDR,
+            device::SetDeviceAddr, tests::ROOTPORT_PCI_START_ADDR, DEFAULT_PCIE_BUS,
         },
     };
 
diff --git a/vmm/sandbox/src/stratovirt/devices/serial.rs b/vmm/sandbox/src/stratovirt/devices/serial.rs
index b117b0f6..8306fa62 100644
--- a/vmm/sandbox/src/stratovirt/devices/serial.rs
+++ b/vmm/sandbox/src/stratovirt/devices/serial.rs
@@ -30,8 +30,6 @@ pub struct SerialDevice {
     pub bus: String,
     #[property(param = "device", predicate = "self.addr.len()>0")]
     pub addr: String,
-    #[property(ignore)]
-    pub transport: Transport,
 }
 
 impl SerialDevice {
@@ -41,13 +39,12 @@ impl SerialDevice {
             id: id.to_string(),
             bus: bus.to_string(),
             addr: "".to_string(),
-            transport,
         }
     }
 }
 
 impl_device_no_bus!(SerialDevice);
-impl_set_get_device_addr!(SerialDevice);
+impl_set_device_addr!(SerialDevice);
 
 #[cfg(test)]
 mod tests {
@@ -56,7 +53,7 @@ mod tests {
         device::Transport,
         param::ToCmdLineParams,
         stratovirt::devices::{
-            device::GetAndSetDeviceAddr, DEFAULT_PCIE_BUS, VIRTIO_SERIAL_CONSOLE_ADDR,
+            device::SetDeviceAddr, tests::VIRTIO_SERIAL_CONSOLE_ADDR, DEFAULT_PCIE_BUS,
         },
     };
 
diff --git a/vmm/sandbox/src/stratovirt/devices/vhost_user_fs.rs b/vmm/sandbox/src/stratovirt/devices/vhost_user_fs.rs
index 89e012c4..fe0ddd19 100644
--- a/vmm/sandbox/src/stratovirt/devices/vhost_user_fs.rs
+++ b/vmm/sandbox/src/stratovirt/devices/vhost_user_fs.rs
@@ -37,7 +37,7 @@ pub struct VhostUserFs {
 }
 
 impl_device_no_bus!(VhostUserFs);
-impl_set_get_device_addr!(VhostUserFs);
+impl_set_device_addr!(VhostUserFs);
 
 impl VhostUserFs {
     pub fn new(id: &str, transport: Transport, chardev: &str, mount_tag: &str, bus: &str) -> Self {
@@ -59,7 +59,7 @@ mod tests {
         device::Transport,
         param::ToCmdLineParams,
         stratovirt::devices::{
-            char::CharDevice, device::GetAndSetDeviceAddr, DEFAULT_PCIE_BUS, VHOST_USER_FS_ADDR,
+            char::CharDevice, device::SetDeviceAddr, tests::VHOST_USER_FS_ADDR, DEFAULT_PCIE_BUS,
         },
     };
 
@@ -93,12 +93,12 @@ mod tests {
         let expected_params: Vec<String> = vec![
             "-chardev",
             "socket,id=virtio-fs-test,path=/path/to/virtiofs.sock,server,nowait",
-            "-device", 
+            "-device",
             "vhost-user-fs-pci,id=vhost-user-fs-test,chardev=virtio-fs-test,tag=myfs,bus=pcie.0,addr=0x4",
-            ]
-        .iter()
-        .map(|s| s.to_string())
-        .collect();
+        ]
+            .iter()
+            .map(|s| s.to_string())
+            .collect();
         assert_eq!(expected_params, result_params);
     }
 }
diff --git a/vmm/sandbox/src/stratovirt/devices/virtio_net.rs b/vmm/sandbox/src/stratovirt/devices/virtio_net.rs
index 3a8ed7d9..ffe676b9 100644
--- a/vmm/sandbox/src/stratovirt/devices/virtio_net.rs
+++ b/vmm/sandbox/src/stratovirt/devices/virtio_net.rs
@@ -93,7 +93,7 @@ impl VirtioNetDevice {
 }
 
 impl_device_no_bus!(VirtioNetDevice);
-impl_set_get_device_addr!(VirtioNetDevice);
+impl_set_device_addr!(VirtioNetDevice);
 
 impl VirtioNetDevice {
     pub fn new() -> Self {
diff --git a/vmm/sandbox/src/stratovirt/devices/vsock.rs b/vmm/sandbox/src/stratovirt/devices/vsock.rs
index f441fc9f..d0fff11f 100644
--- a/vmm/sandbox/src/stratovirt/devices/vsock.rs
+++ b/vmm/sandbox/src/stratovirt/devices/vsock.rs
@@ -47,7 +47,7 @@ pub struct VSockDevice {
 }
 
 impl_device_no_bus!(VSockDevice);
-impl_set_get_device_addr!(VSockDevice);
+impl_set_device_addr!(VSockDevice);
 
 impl VSockDevice {
     pub fn new(context_id: u64, transport: Transport, bus: &str, vhost_fd: i32) -> Self {
@@ -88,7 +88,7 @@ mod tests {
     use crate::{
         device::Transport,
         param::ToCmdLineParams,
-        stratovirt::devices::{device::GetAndSetDeviceAddr, DEFAULT_PCIE_BUS, VHOST_VSOCK_ADDR},
+        stratovirt::devices::{device::SetDeviceAddr, tests::VHOST_VSOCK_ADDR, DEFAULT_PCIE_BUS},
     };
 
     #[test]
@@ -106,9 +106,9 @@ mod tests {
             "-device",
             "vhost-vsock-pci,id=vsock-1224150961,guest-cid=1224150961,bus=pcie.0,addr=0x3,vhostfd=100",
         ]
-        .iter()
-        .map(|s| s.to_string())
-        .collect();
+            .iter()
+            .map(|s| s.to_string())
+            .collect();
         assert_eq!(expected_params, vhost_vsock_device_cmd_params);
     }
 }
diff --git a/vmm/sandbox/src/stratovirt/mod.rs b/vmm/sandbox/src/stratovirt/mod.rs
index 57404203..724a93c2 100644
--- a/vmm/sandbox/src/stratovirt/mod.rs
+++ b/vmm/sandbox/src/stratovirt/mod.rs
@@ -242,7 +242,30 @@ impl VM for StratoVirtVM {
         }
     }
 
-    async fn hot_detach(&mut self, _id: &str) -> Result<()> {
+    async fn hot_detach(&mut self, id: &str) -> Result<()> {
+        let index = self.hot_attached_devices.iter().position(|x| x.id() == id);
+        let device = match index {
+            None => {
+                return Ok(());
+            }
+            Some(index) => self.hot_attached_devices.remove(index),
+        };
+
+        let client = match self.get_client() {
+            Ok(c) => c,
+            Err(e) => {
+                // rollback, add it back to the list
+                self.hot_attached_devices.push(device);
+                return Err(e);
+            }
+        };
+
+        if let Err(e) = device.execute_hot_detach(client).await {
+            // rollback, add it back to the list
+            self.hot_attached_devices.push(device);
+            return Err(e);
+        }
+        self.detach_from_bus(id);
         Ok(())
     }
 
@@ -262,12 +285,12 @@ impl VM for StratoVirtVM {
 
     async fn vcpus(&self) -> Result<VcpuThreads> {
         let client = self.get_client()?;
-        let result = client.execute(qmp::query_cpus {}).await?;
+        let result = client.execute(qmp::QueryCpus {}).await?;
         let mut vcpu_threads_map: HashMap<i64, i64> = HashMap::new();
         for vcpu_info in result.iter() {
             match vcpu_info {
-                CpuInfo::Arm { base, .. } | CpuInfo::x86 { base, .. } => {
-                    vcpu_threads_map.insert(base.CPU, base.thread_id);
+                CpuInfo::Arm { base, .. } | CpuInfo::X86 { base, .. } => {
+                    vcpu_threads_map.insert(base.cpu, base.thread_id);
                 }
             }
         }
@@ -544,6 +567,24 @@ impl StratoVirtVM {
             .start()
             .map_err(|e| Error::Other(anyhow!("start virtiofs daemon process failed: {}", e)))
     }
+
+    fn detach_from_bus(&mut self, device_id: &str) {
+        self.devices
+            .iter_mut()
+            .filter_map(|x| x.bus())
+            .for_each(|b| {
+                if let Some(x) = b.slots.iter_mut().find(|s| {
+                    if let SlotStatus::Occupied(id) = &s.status {
+                        if id == device_id {
+                            return true;
+                        }
+                    }
+                    false
+                }) {
+                    x.status = SlotStatus::Empty;
+                }
+            });
+    }
 }
 
 impl_recoverable!(StratoVirtVM);
diff --git a/vmm/sandbox/src/stratovirt/qmp.rs b/vmm/sandbox/src/stratovirt/qmp.rs
index 135cf4e5..0c1c008e 100644
--- a/vmm/sandbox/src/stratovirt/qmp.rs
+++ b/vmm/sandbox/src/stratovirt/qmp.rs
@@ -14,16 +14,14 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-#![allow(warnings)]
-
 use qapi::qmp::QmpCommand;
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct query_cpus {}
+pub struct QueryCpus {}
 
-impl QmpCommand for query_cpus {}
-impl ::qapi_spec::Command for query_cpus {
+impl QmpCommand for QueryCpus {}
+impl ::qapi_spec::Command for QueryCpus {
     const NAME: &'static str = "query-cpus";
     const ALLOW_OOB: bool = false;
 
@@ -33,7 +31,7 @@ impl ::qapi_spec::Command for query_cpus {
 #[derive(Debug, Copy, Clone, Serialize, Deserialize, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub enum CpuInfoArch {
     #[serde(rename = "x86")]
-    x86,
+    X86,
     #[serde(rename = "Arm")]
     Arm,
 }
@@ -52,7 +50,7 @@ unsafe impl ::qapi_spec::Enum for CpuInfoArch {
     }
 
     const COUNT: usize = 2;
-    const VARIANTS: &'static [Self] = &[CpuInfoArch::x86, CpuInfoArch::Arm];
+    const VARIANTS: &'static [Self] = &[CpuInfoArch::X86, CpuInfoArch::Arm];
     const NAMES: &'static [&'static str] = &["x86", "Arm"];
 }
 
@@ -66,10 +64,10 @@ pub enum CpuInfo {
         base: CpuInfoBase,
         #[serde(flatten)]
         #[serde(rename = "Arm")]
-        Arm: CpuInfoArm,
+        arm: CpuInfoArm,
     },
     #[serde(rename = "x86")]
-    x86 {
+    X86 {
         #[serde(flatten)]
         #[serde(rename = "base")]
         base: CpuInfoBase,
@@ -82,31 +80,21 @@ pub enum CpuInfo {
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct CpuInfoBase {
     #[serde(rename = "CPU")]
-    pub CPU: i64,
+    pub cpu: i64,
     #[serde(rename = "current")]
     pub current: bool,
     #[serde(rename = "halted")]
     pub halted: bool,
     #[serde(rename = "qom_path")]
-    pub qom_path: ::std::string::String,
+    pub qom_path: String,
     #[serde(rename = "thread_id")]
     pub thread_id: i64,
 }
 
-impl CpuInfo {
-    pub fn arch(&self) -> CpuInfoArch {
-        match *self {
-            CpuInfo::Arm { .. } => CpuInfoArch::Arm,
-
-            CpuInfo::x86 { .. } => CpuInfoArch::x86,
-        }
-    }
-}
-
 impl From<(CpuInfoArm, CpuInfoBase)> for CpuInfo {
     fn from(val: (CpuInfoArm, CpuInfoBase)) -> Self {
         Self::Arm {
-            Arm: val.0,
+            arm: val.0,
             base: val.1,
         }
     }
@@ -114,7 +102,7 @@ impl From<(CpuInfoArm, CpuInfoBase)> for CpuInfo {
 
 impl From<(CpuInfoX86, CpuInfoBase)> for CpuInfo {
     fn from(val: (CpuInfoX86, CpuInfoBase)) -> Self {
-        Self::x86 {
+        Self::X86 {
             x86: val.0,
             base: val.1,
         }
diff --git a/vmm/sandbox/src/stratovirt/qmp_client.rs b/vmm/sandbox/src/stratovirt/qmp_client.rs
index d2eb3e17..ec3421bf 100644
--- a/vmm/sandbox/src/stratovirt/qmp_client.rs
+++ b/vmm/sandbox/src/stratovirt/qmp_client.rs
@@ -31,14 +31,11 @@ use tokio::{
         oneshot::{channel, Sender},
         Mutex,
     },
-    task::JoinHandle,
 };
 
 pub struct QmpClient {
     qmp: QapiService<QmpStreamTokio<WriteHalf<UnixStream>>>,
     watchers: Arc<Mutex<Vec<QmpEventWatcher>>>,
-    #[allow(dead_code)]
-    handle: JoinHandle<()>,
 }
 
 pub struct QmpEventWatcher {
@@ -54,7 +51,7 @@ impl QmpClient {
         let event_watchers = Arc::new(Mutex::new(Vec::<QmpEventWatcher>::new()));
 
         let w_clone = event_watchers.clone();
-        let handle = tokio::spawn(async move {
+        tokio::spawn(async move {
             while let Some(Ok(event)) = events.next().await {
                 let mut ws = w_clone.lock().await;
                 let mut retained = vec![];
@@ -76,7 +73,6 @@ impl QmpClient {
         let client = Self {
             qmp: service,
             watchers: event_watchers,
-            handle,
         };
         Ok(client)
     }
diff --git a/vmm/sandbox/src/utils.rs b/vmm/sandbox/src/utils.rs
index 729473bf..0cb754fd 100644
--- a/vmm/sandbox/src/utils.rs
+++ b/vmm/sandbox/src/utils.rs
@@ -67,7 +67,7 @@ pub fn get_netns(data: &SandboxData) -> String {
         if let Some(l) = &spec.linux {
             for ns in &l.namespaces {
                 if ns.r#type == NET_NAMESPACE {
-                    netns = ns.path.clone();
+                    netns.clone_from(&ns.path);
                 }
             }
         }
diff --git a/vmm/task/src/container.rs b/vmm/task/src/container.rs
index 0499affb..e9c53bb7 100644
--- a/vmm/task/src/container.rs
+++ b/vmm/task/src/container.rs
@@ -62,11 +62,6 @@ use crate::{
     util::{read_io, read_storages, wait_pid},
 };
 
-#[allow(dead_code)]
-pub const GROUP_LABELS: [&str; 2] = [
-    "io.containerd.runc.v2.group",
-    "io.kubernetes.cri.sandbox-id",
-];
 pub const INIT_PID_FILE: &str = "init.pid";
 
 const STORAGE_ANNOTATION: &str = "io.kuasar.storages";
diff --git a/vmm/task/src/device.rs b/vmm/task/src/device.rs
index bf78a060..d271fbcc 100644
--- a/vmm/task/src/device.rs
+++ b/vmm/task/src/device.rs
@@ -61,14 +61,11 @@ pub trait DeviceMatcher: Sync + Send + 'static {
 pub type DeviceConverter = fn(&Uevent) -> Option<Device>;
 
 pub struct DeviceSubscriber {
-    #[allow(dead_code)]
-    pub(crate) id: u64,
     pub(crate) tx: Sender<Device>,
     pub(crate) matcher: Box<dyn DeviceMatcher>,
 }
 
 pub struct DeviceSubscription {
-    #[allow(dead_code)]
     pub(crate) id: u64,
     pub(crate) rx: Receiver<Device>,
 }
@@ -106,7 +103,6 @@ impl DeviceMonitor {
         ss.insert(
             id,
             DeviceSubscriber {
-                id,
                 tx,
                 matcher: Box::new(matcher),
             },
@@ -115,7 +111,6 @@ impl DeviceMonitor {
         DeviceSubscription { id, rx }
     }
 
-    #[allow(dead_code)]
     pub async fn unsubscribe(&self, id: u64) {
         let mut internal = self.internal.lock().await;
         let ss = &mut internal.subscribers;
@@ -296,24 +291,17 @@ impl Uevent {
     }
 }
 
-#[allow(dead_code)]
-pub const SCSI_HOST_CHANNEL: &str = "0:0:";
 pub const SCSI_BLOCK_SUFFIX: &str = "block";
 pub const SYSFS_SCSI_HOST_PATH: &str = "/sys/class/scsi_host";
 pub const SYSFS_SCSI_DEVICE_PATH: &str = "/sys/class/scsi_device";
 pub const SYSFS_BLK_DEVICE_PATH: &str = "/sys/class/block";
 pub const SYSFS_PCI_BUS_RESCAN_FILE: &str = "/sys/bus/pci/rescan";
-#[allow(dead_code)]
-pub const SYSFS_PCI_BUS_PREFIX: &str = "/sys/bus/pci/devices";
 pub const SYSTEM_DEV_PATH: &str = "/dev";
 
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub enum DeviceType {
-    #[allow(dead_code)]
     Blk,
     Scsi,
-    #[allow(dead_code)]
-    Ephemeral,
 }
 
 #[derive(Clone, Debug)]
diff --git a/vmm/task/src/io.rs b/vmm/task/src/io.rs
index f943e8db..6401d994 100644
--- a/vmm/task/src/io.rs
+++ b/vmm/task/src/io.rs
@@ -49,7 +49,6 @@ use tokio_vsock::{VsockListener, VsockStream};
 use crate::{device::SYSTEM_DEV_PATH, vsock};
 
 pub struct ProcessIO {
-    pub uri: Option<String>,
     pub io: Option<Arc<dyn Io>>,
     pub copy: bool,
 }
@@ -65,7 +64,6 @@ pub fn create_io(
     if stdio.is_null() {
         let nio = NullIo::new().map_err(io_error!(e, "new Null Io"))?;
         let pio = ProcessIO {
-            uri: None,
             io: Some(Arc::new(nio)),
             copy: false,
         };
@@ -73,20 +71,15 @@ pub fn create_io(
     }
     let stdout = stdio.stdout.as_str();
     let scheme_path = stdout.trim().split("://").collect::<Vec<&str>>();
-    let scheme: &str;
-    let uri: String;
-    if scheme_path.len() <= 1 {
+    let scheme = if scheme_path.len() <= 1 {
         // no scheme specified
         // default schema to fifo
-        uri = format!("fifo://{}", stdout);
-        scheme = "fifo"
+        "fifo"
     } else {
-        uri = stdout.to_string();
-        scheme = scheme_path[0];
-    }
+        scheme_path[0]
+    };
 
     let mut pio = ProcessIO {
-        uri: Some(uri),
         io: None,
         copy: false,
     };
diff --git a/vmm/task/src/mount.rs b/vmm/task/src/mount.rs
index 262bed26..8d63afa7 100644
--- a/vmm/task/src/mount.rs
+++ b/vmm/task/src/mount.rs
@@ -16,11 +16,7 @@ use tokio::{
 use crate::StaticMount;
 
 pub const SYSFS_CGROUPPATH: &str = "/sys/fs/cgroup";
-#[allow(dead_code)]
-pub const SYSFS_ONLINE_FILE: &str = "online";
 
-#[allow(dead_code)]
-pub const PROC_MOUNTSTATS: &str = "/proc/self/mountstats";
 pub const PROC_CGROUPS: &str = "/proc/cgroups";
 
 lazy_static! {
diff --git a/vmm/task/src/netlink.rs b/vmm/task/src/netlink.rs
index 70ad5240..31429ea5 100644
--- a/vmm/task/src/netlink.rs
+++ b/vmm/task/src/netlink.rs
@@ -47,9 +47,6 @@ impl fmt::Display for LinkFilter<'_> {
 pub enum AddressFilter {
     /// Return addresses that belong to the given interface.
     LinkIndex(u32),
-    /// Get addresses with the given prefix.
-    #[allow(dead_code)]
-    IpAddress(IpAddr),
 }
 
 /// A high level wrapper for netlink (and `rtnetlink` crate) for use by the Agent's RPC.
@@ -204,7 +201,6 @@ impl Handle {
         if let Some(filter) = filter.into() {
             request = match filter {
                 AddressFilter::LinkIndex(index) => request.set_link_index_filter(index),
-                AddressFilter::IpAddress(addr) => request.set_address_filter(addr),
             };
         };
 
@@ -491,22 +487,6 @@ impl Link {
             .unwrap_or_default()
     }
 
-    /// Extract Mac address.
-    #[allow(dead_code)]
-    fn address(&self) -> String {
-        use packet::nlas::link::Nla;
-        self.nlas
-            .iter()
-            .find_map(|n| {
-                if let Nla::Address(data) = n {
-                    format_address(data).ok()
-                } else {
-                    None
-                }
-            })
-            .unwrap_or_default()
-    }
-
     /// Returns whether the link is UP
     fn is_up(&self) -> bool {
         self.header.flags & packet::rtnl::constants::IFF_UP > 0
@@ -515,18 +495,6 @@ impl Link {
     fn index(&self) -> u32 {
         self.header.index
     }
-
-    #[allow(dead_code)]
-    fn mtu(&self) -> Option<u64> {
-        use packet::nlas::link::Nla;
-        self.nlas.iter().find_map(|n| {
-            if let Nla::Mtu(mtu) = n {
-                Some(*mtu as u64)
-            } else {
-                None
-            }
-        })
-    }
 }
 
 impl From<packet::LinkMessage> for Link {
@@ -576,11 +544,6 @@ impl Address {
         self.0.header.family == packet::constants::AF_INET6 as u8
     }
 
-    #[allow(dead_code)]
-    fn prefix(&self) -> u8 {
-        self.0.header.prefix_len
-    }
-
     fn address(&self) -> String {
         use packet::nlas::address::Nla;
         self.0
diff --git a/vmm/task/src/sandbox.rs b/vmm/task/src/sandbox.rs
index 8321a15b..1c8e0da9 100644
--- a/vmm/task/src/sandbox.rs
+++ b/vmm/task/src/sandbox.rs
@@ -135,6 +135,7 @@ impl SandboxResources {
                 e,
                 format!("timeout waiting for device with addr {} ready", addr)
             ))?;
+        self.device_monitor.unsubscribe(s.id).await;
         res.ok_or_else(|| other!("can not get device with addr {}", addr))
     }
 }
diff --git a/wasm/src/sandbox.rs b/wasm/src/sandbox.rs
index ddc13742..84354869 100644
--- a/wasm/src/sandbox.rs
+++ b/wasm/src/sandbox.rs
@@ -134,7 +134,7 @@ impl WasmSandbox {
     async fn start(&mut self) -> Result<()> {
         let task = self.start_task_service().await?;
         let task_address = format!("unix://{}/task.sock", self.base_dir);
-        self.data.task_address = task_address.clone();
+        self.data.task_address.clone_from(&task_address);
         let task_service = create_task(Arc::new(Box::new(task)));
         let mut server = Server::new().register_service(task_service);
         server = server
@@ -155,7 +155,7 @@ impl WasmSandbox {
     ) -> Result<TaskService<WasmEdgeContainerFactory, WasmEdgeContainer>> {
         let (tx, mut rx) = channel(128);
         let mut factory = WasmEdgeContainerFactory::default();
-        factory.netns = self.data.netns.clone();
+        factory.netns.clone_from(&self.data.netns);
         let task = TaskService {
             factory,
             containers: Arc::new(Default::default()),
diff --git a/wasm/src/wasmedge.rs b/wasm/src/wasmedge.rs
index 392a388b..1249a502 100644
--- a/wasm/src/wasmedge.rs
+++ b/wasm/src/wasmedge.rs
@@ -14,8 +14,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-#![cfg(feature = "wasmedge")]
-
 use std::{
     fs::OpenOptions,
     os::unix::prelude::{IntoRawFd, RawFd},