diff --git a/kernel/comps/virtio/src/device/network/device.rs b/kernel/comps/virtio/src/device/network/device.rs
index edda9a4a4..31428b4c1 100644
--- a/kernel/comps/virtio/src/device/network/device.rs
+++ b/kernel/comps/virtio/src/device/network/device.rs
@@ -1,12 +1,10 @@
 // SPDX-License-Identifier: MPL-2.0
 
-use alloc::{boxed::Box, string::ToString, sync::Arc, vec::Vec};
+use alloc::{boxed::Box, string::ToString, sync::Arc};
 use core::{fmt::Debug, hint::spin_loop, mem::size_of};
 
 use aster_frame::{offset_of, sync::SpinLock, trap::TrapFrame};
-use aster_network::{
-    AnyNetworkDevice, EthernetAddr, NetDeviceIrqHandler, RxBuffer, TxBuffer, VirtioNetError,
-};
+use aster_network::{AnyNetworkDevice, EthernetAddr, RxBuffer, TxBuffer, VirtioNetError};
 use aster_util::{field_ptr, slot_vec::SlotVec};
 use log::debug;
 use smoltcp::phy::{DeviceCapabilities, Medium};
@@ -24,7 +22,6 @@ pub struct NetworkDevice {
     send_queue: VirtQueue,
     recv_queue: VirtQueue,
     rx_buffers: SlotVec<RxBuffer>,
-    callbacks: Vec<Box<dyn NetDeviceIrqHandler>>,
     transport: Box<dyn VirtioTransport>,
 }
 
@@ -76,7 +73,6 @@ impl NetworkDevice {
             recv_queue,
             rx_buffers,
             transport,
-            callbacks: Vec::new(),
         };
 
         /// Interrupt handler if network device config space changes
@@ -220,4 +216,3 @@ const QUEUE_RECV: u16 = 0;
 const QUEUE_SEND: u16 = 1;
 
 const QUEUE_SIZE: u16 = 64;
-const RX_BUFFER_LEN: usize = 4096;
diff --git a/kernel/comps/virtio/src/queue.rs b/kernel/comps/virtio/src/queue.rs
index 23695c725..c7e05dfd3 100644
--- a/kernel/comps/virtio/src/queue.rs
+++ b/kernel/comps/virtio/src/queue.rs
@@ -226,77 +226,6 @@ impl VirtQueue {
         Ok(head)
     }
 
-    /// Add buffers to the virtqueue, return a token. **This function will be removed in the future.**
-    ///
-    /// Ref: linux virtio_ring.c virtqueue_add
-    pub fn add_buf(&mut self, inputs: &[&[u8]], outputs: &[&mut [u8]]) -> Result<u16, QueueError> {
-        // FIXME: use `DmaSteam` for inputs and outputs. Now because the upper device driver lacks the
-        // ability to safely construct DmaStream from slice, slice is still used here.
-        // pub fn add(
-        //     &mut self,
-        //     inputs: &[&DmaStream],
-        //     outputs: &[&mut DmaStream],
-        // ) -> Result<u16, QueueError> {
-
-        if inputs.is_empty() && outputs.is_empty() {
-            return Err(QueueError::InvalidArgs);
-        }
-        if inputs.len() + outputs.len() + self.num_used as usize > self.queue_size as usize {
-            return Err(QueueError::BufferTooSmall);
-        }
-
-        // allocate descriptors from free list
-        let head = self.free_head;
-        let mut last = self.free_head;
-        for input in inputs.iter() {
-            let desc = &self.descs[self.free_head as usize];
-            set_buf_slice(&desc.borrow_vm().restrict::<TRights![Write, Dup]>(), input);
-            field_ptr!(desc, Descriptor, flags)
-                .write(&DescFlags::NEXT)
-                .unwrap();
-            last = self.free_head;
-            self.free_head = field_ptr!(desc, Descriptor, next).read().unwrap();
-        }
-        for output in outputs.iter() {
-            let desc = &mut self.descs[self.free_head as usize];
-            set_buf_slice(&desc.borrow_vm().restrict::<TRights![Write, Dup]>(), output);
-            field_ptr!(desc, Descriptor, flags)
-                .write(&(DescFlags::NEXT | DescFlags::WRITE))
-                .unwrap();
-            last = self.free_head;
-            self.free_head = field_ptr!(desc, Descriptor, next).read().unwrap();
-        }
-        // set last_elem.next = NULL
-        {
-            let desc = &mut self.descs[last as usize];
-            let mut flags: DescFlags = field_ptr!(desc, Descriptor, flags).read().unwrap();
-            flags.remove(DescFlags::NEXT);
-            field_ptr!(desc, Descriptor, flags).write(&flags).unwrap();
-        }
-        self.num_used += (inputs.len() + outputs.len()) as u16;
-
-        let avail_slot = self.avail_idx & (self.queue_size - 1);
-
-        {
-            let ring_ptr: SafePtr<[u16; 64], &DmaCoherent> =
-                field_ptr!(&self.avail, AvailRing, ring);
-            let mut ring_slot_ptr = ring_ptr.cast::<u16>();
-            ring_slot_ptr.add(avail_slot as usize);
-            ring_slot_ptr.write(&head).unwrap();
-        }
-        // write barrier
-        fence(Ordering::SeqCst);
-
-        // increase head of avail ring
-        self.avail_idx = self.avail_idx.wrapping_add(1);
-        field_ptr!(&self.avail, AvailRing, idx)
-            .write(&self.avail_idx)
-            .unwrap();
-
-        fence(Ordering::SeqCst);
-        Ok(head)
-    }
-
     /// Whether there is a used element that can pop.
     pub fn can_pop(&self) -> bool {
         // read barrier
@@ -421,6 +350,8 @@ type DescriptorPtr<'a> = SafePtr<Descriptor, &'a DmaCoherent, TRightSet<TRights!
 
 #[inline]
 fn set_dma_buf<T: DmaBuf>(desc_ptr: &DescriptorPtr, buf: &T) {
+    // TODO: skip the empty dma buffer or just return error?
+    debug_assert_ne!(buf.len(), 0);
     let daddr = buf.daddr();
     field_ptr!(desc_ptr, Descriptor, addr)
         .write(&(daddr as u64))
@@ -430,21 +361,6 @@ fn set_dma_buf<T: DmaBuf>(desc_ptr: &DescriptorPtr, buf: &T) {
         .unwrap();
 }
 
-#[inline]
-#[allow(clippy::type_complexity)]
-fn set_buf_slice(desc_ptr: &DescriptorPtr, buf: &[u8]) {
-    // FIXME: use `DmaSteam` for buf. Now because the upper device driver lacks the
-    // ability to safely construct DmaStream from slice, slice is still used here.
-    let va = buf.as_ptr() as usize;
-    let pa = aster_frame::vm::vaddr_to_paddr(va).unwrap();
-    field_ptr!(desc_ptr, Descriptor, addr)
-        .write(&(pa as u64))
-        .unwrap();
-    field_ptr!(desc_ptr, Descriptor, len)
-        .write(&(buf.len() as u32))
-        .unwrap();
-}
-
 bitflags! {
     /// Descriptor flags
     #[derive(Pod, Default)]