diff --git a/kernel/Cargo.lock b/kernel/Cargo.lock
index 7b07896..37da659 100644
--- a/kernel/Cargo.lock
+++ b/kernel/Cargo.lock
@@ -75,7 +75,6 @@ dependencies = [
  "spin 0.9.8",
  "static_assertions",
  "uart_16550",
- "vspace",
 ]
 
 [[package]]
@@ -236,13 +235,6 @@ version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
 
-[[package]]
-name = "vspace"
-version = "0.1.0"
-dependencies = [
- "bitflags 2.5.0",
-]
-
 [[package]]
 name = "x86"
 version = "0.52.0"
diff --git a/kernel/Cargo.toml b/kernel/Cargo.toml
index 88f02af..1c90e1c 100644
--- a/kernel/Cargo.toml
+++ b/kernel/Cargo.toml
@@ -6,14 +6,20 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
-default = ["arch_riscv64", "board_virt", "log_color"]
+default = ["riscv.board.virt", "log_color"]
 
-arch_riscv64 = ["vspace/riscv_sv39"]
-# TODO: riscv32 not supported yet
-arch_riscv32 = []
+riscv = []
 
-board_default = []
-board_virt = []
+"riscv.pagetable.sv32" = []
+"riscv.pagetable.sv39" = []
+"riscv.pagetable.sv48" = []
+"riscv.pagetable.sv57" = []
+
+"riscv.riscv64" = ["riscv", "riscv.pagetable.sv39"]
+"riscv.riscv32" = ["riscv", "riscv.pagetable.sv32"]
+
+"riscv.board.default" = ["riscv.riscv64"]
+"riscv.board.virt" = ["riscv.riscv64"]
 
 log_color = []
 
@@ -26,7 +32,6 @@ lto = "thin"
 
 [dependencies]
 api = { path = "../api" }
-vspace = { path = "../lib/vspace", default-features = false }
 
 bitflags = "2.4"
 cfg-if = "1.0"
@@ -35,8 +40,10 @@ lazy_static = { version = "1.4", features = ["spin_no_std"] }
 log = "0.4"
 num-derive = "0.4"
 num-traits = { version = "0.2", default-features = false }
-riscv = { version = "0.11", features = ["s-mode"] }
-sbi-rt = { version = "0.0" }
 spin = "0.9"
 static_assertions = "1.1"
 uart_16550 = "0.3"
+
+[target.'cfg(any(target_arch = "riscv32", target_arch = "riscv64"))'.dependencies]
+riscv = { version = "0.11", features = ["s-mode"] }
+sbi-rt = { version = "0.0" }
diff --git a/kernel/src/arch/mod.rs b/kernel/src/arch/mod.rs
index eb24e11..1bfeaa9 100644
--- a/kernel/src/arch/mod.rs
+++ b/kernel/src/arch/mod.rs
@@ -1,7 +1,7 @@
 pub use arch::*;
 
 // Arch Level
-#[cfg(any(feature = "arch_riscv64", feature = "arch_riscv32"))]
+#[cfg(feature = "riscv")]
 #[path = "riscv/mod.rs"]
 #[allow(clippy::module_inception)]
 mod arch;
diff --git a/kernel/src/arch/riscv/lowlevel.rs b/kernel/src/arch/riscv/lowlevel.rs
index 487a674..f1d224e 100644
--- a/kernel/src/arch/riscv/lowlevel.rs
+++ b/kernel/src/arch/riscv/lowlevel.rs
@@ -1,4 +1,4 @@
-use log::{error, warn};
+use log::error;
 
 use crate::plat::lowlevel::{Hardware, LowLevel};
 
diff --git a/kernel/src/arch/riscv/mod.rs b/kernel/src/arch/riscv/mod.rs
index 2ab5f2c..f3e5130 100644
--- a/kernel/src/arch/riscv/mod.rs
+++ b/kernel/src/arch/riscv/mod.rs
@@ -1,10 +1,11 @@
 use cfg_if::cfg_if;
 
 cfg_if! {
-    if #[cfg(feature = "board_virt")] {
+    if #[cfg(feature = "riscv.board.virt")] {
         #[path = "board/virt/mod.rs"]
         mod board;
     } else {
+        // fall back to default
         #[path = "board/default/mod.rs"]
         mod board;
     }
@@ -19,3 +20,4 @@ mod lowlevel;
 mod timer;
 mod tls;
 pub mod trap;
+pub mod vspace;
diff --git a/kernel/src/arch/riscv/trap.rs b/kernel/src/arch/riscv/trap.rs
index 478c3c7..5f96b21 100644
--- a/kernel/src/arch/riscv/trap.rs
+++ b/kernel/src/arch/riscv/trap.rs
@@ -9,9 +9,9 @@ use crate::plat::timer::{Timer, TimerOps};
 use crate::plat::trap::{Trap, TrapContextOps, TrapOps};
 
 cfg_if! {
-    if #[cfg(feature = "arch_riscv64")] {
+    if #[cfg(feature = "riscv.riscv64")] {
         core::arch::global_asm!(include_str!("./asm/trap64.S"));
-    } else if #[cfg(feature = "arch_riscv32")] {
+    } else if #[cfg(feature = "riscv.riscv32")] {
         core::arch::global_asm!(include_str!("./asm/trap32.S"));
     }
 }
diff --git a/lib/vspace/src/paging/arch/riscv/entry.rs b/kernel/src/arch/riscv/vspace/entry.rs
similarity index 96%
rename from lib/vspace/src/paging/arch/riscv/entry.rs
rename to kernel/src/arch/riscv/vspace/entry.rs
index 4cc16e5..1a4ba5b 100644
--- a/lib/vspace/src/paging/arch/riscv/entry.rs
+++ b/kernel/src/arch/riscv/vspace/entry.rs
@@ -1,5 +1,5 @@
-use crate::addr::{AddressOps, PhysAddr};
-use crate::paging::{MapAttr, PageTableEntryOps};
+use crate::vspace::addr::{AddressOps, PhysAddr};
+use crate::vspace::paging::{MapAttr, PageTableEntryOps};
 use bitflags::bitflags;
 
 bitflags! {
@@ -73,7 +73,7 @@ impl From<MapAttr> for PTEFlags {
     }
 }
 
-#[cfg(feature = "riscv_sv39")]
+#[cfg(feature = "riscv.pagetable.sv39")]
 impl PhysAddr {
     const PA_PPN_MASK: u64 = ((1 << Self::PPN_BITS) - 1) << Self::PG_OFFSET;
     const PG_OFFSET: u64 = 12;
diff --git a/lib/vspace/src/paging/arch/riscv/mod.rs b/kernel/src/arch/riscv/vspace/mod.rs
similarity index 87%
rename from lib/vspace/src/paging/arch/riscv/mod.rs
rename to kernel/src/arch/riscv/vspace/mod.rs
index c2d5f78..e26f088 100644
--- a/lib/vspace/src/paging/arch/riscv/mod.rs
+++ b/kernel/src/arch/riscv/vspace/mod.rs
@@ -1,5 +1,6 @@
 mod entry;
 mod table;
+mod utils;
 
 pub use entry::PageTableEntry;
 pub use table::PageTable;
diff --git a/lib/vspace/src/paging/arch/riscv/table.rs b/kernel/src/arch/riscv/vspace/table.rs
similarity index 94%
rename from lib/vspace/src/paging/arch/riscv/table.rs
rename to kernel/src/arch/riscv/vspace/table.rs
index d32f977..8bda170 100644
--- a/lib/vspace/src/paging/arch/riscv/table.rs
+++ b/kernel/src/arch/riscv/vspace/table.rs
@@ -1,11 +1,12 @@
-use crate::addr::{AddressOps, PhysAddr, VirtAddr};
-use crate::paging::{
-    MapAttr, PageError, PageResult, PageSize, PageTableEntry, PageTableEntryOps, PageTableOps,
+use super::entry::PageTableEntry;
+use crate::vspace::addr::{AddressOps, PhysAddr, VirtAddr};
+use crate::vspace::paging::{
+    MapAttr, PageError, PageResult, PageSize, PageTableEntryOps, PageTableOps,
 };
 
 const PAGE_SIZE: usize = 4096;
 
-#[cfg(feature = "riscv_sv39")]
+#[cfg(feature = "riscv.pagetable.sv39")]
 impl VirtAddr {
     const PG_OFFSET: usize = 12;
     const VPN_BITS: usize = 9;
@@ -62,7 +63,7 @@ impl PageTable {
 impl PageTableOps for PageTable {
     type Entry = PageTableEntry;
 
-    #[cfg(feature = "riscv_sv39")]
+    #[cfg(feature = "riscv.pagetable.sv39")]
     const MAX_PAGE_SIZE: PageSize = PageSize::Giga;
 
     unsafe fn from_va(from: VirtAddr) -> &'static mut Self {
diff --git a/kernel/src/main.rs b/kernel/src/main.rs
index 188d3f7..a76d4ea 100644
--- a/kernel/src/main.rs
+++ b/kernel/src/main.rs
@@ -24,6 +24,7 @@ mod logging;
 mod objects;
 mod plat;
 mod utils;
+mod vspace;
 
 // test infrastructure
 #[cfg(test)]
diff --git a/kernel/src/utils/extern_addr.rs b/kernel/src/utils/extern_addr.rs
index 91f237b..dbcdc13 100644
--- a/kernel/src/utils/extern_addr.rs
+++ b/kernel/src/utils/extern_addr.rs
@@ -1,4 +1,4 @@
-use vspace::addr::PhysAddr;
+use crate::vspace::addr::PhysAddr;
 
 extern "C" {
     pub type ExternSymbol;
diff --git a/lib/vspace/src/addr.rs b/kernel/src/vspace/addr.rs
similarity index 100%
rename from lib/vspace/src/addr.rs
rename to kernel/src/vspace/addr.rs
diff --git a/lib/vspace/src/lib.rs b/kernel/src/vspace/mod.rs
similarity index 71%
rename from lib/vspace/src/lib.rs
rename to kernel/src/vspace/mod.rs
index 713778a..1ffdf9a 100644
--- a/lib/vspace/src/lib.rs
+++ b/kernel/src/vspace/mod.rs
@@ -1,4 +1,2 @@
-#![no_std]
-
 pub mod addr;
 pub mod paging;
diff --git a/lib/vspace/src/paging/entry.rs b/kernel/src/vspace/paging/entry.rs
similarity index 95%
rename from lib/vspace/src/paging/entry.rs
rename to kernel/src/vspace/paging/entry.rs
index 3f6e2e8..bb90eee 100644
--- a/lib/vspace/src/paging/entry.rs
+++ b/kernel/src/vspace/paging/entry.rs
@@ -1,4 +1,4 @@
-use crate::addr::PhysAddr;
+use crate::vspace::addr::PhysAddr;
 use bitflags::bitflags;
 use core::fmt::Debug;
 
diff --git a/lib/vspace/src/paging/mod.rs b/kernel/src/vspace/paging/mod.rs
similarity index 64%
rename from lib/vspace/src/paging/mod.rs
rename to kernel/src/vspace/paging/mod.rs
index 8775615..528a978 100644
--- a/lib/vspace/src/paging/mod.rs
+++ b/kernel/src/vspace/paging/mod.rs
@@ -1,7 +1,6 @@
-mod arch;
 mod entry;
 mod table;
 
-pub use arch::*;
+pub use crate::arch::vspace::*;
 pub use entry::*;
 pub use table::*;
diff --git a/lib/vspace/src/paging/table.rs b/kernel/src/vspace/paging/table.rs
similarity index 97%
rename from lib/vspace/src/paging/table.rs
rename to kernel/src/vspace/paging/table.rs
index 018ff33..594f57a 100644
--- a/lib/vspace/src/paging/table.rs
+++ b/kernel/src/vspace/paging/table.rs
@@ -1,5 +1,5 @@
 use super::{MapAttr, PageTableEntryOps};
-use crate::addr::{PhysAddr, VirtAddr};
+use crate::vspace::addr::{PhysAddr, VirtAddr};
 use core::fmt::Debug;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
diff --git a/lib/vspace/Cargo.lock b/lib/vspace/Cargo.lock
deleted file mode 100644
index be451d6..0000000
--- a/lib/vspace/Cargo.lock
+++ /dev/null
@@ -1,16 +0,0 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
-version = 3
-
-[[package]]
-name = "bitflags"
-version = "2.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf4b9d6a944f767f8e5e0db018570623c85f3d925ac718db4e06d0187adb21c1"
-
-[[package]]
-name = "vspace"
-version = "0.1.0"
-dependencies = [
- "bitflags",
-]
diff --git a/lib/vspace/Cargo.toml b/lib/vspace/Cargo.toml
deleted file mode 100644
index 4719ae4..0000000
--- a/lib/vspace/Cargo.toml
+++ /dev/null
@@ -1,13 +0,0 @@
-[package]
-name = "vspace"
-version = "0.1.0"
-edition = "2021"
-
-[features]
-default = ["arch_riscv", "riscv_sv39"]
-
-arch_riscv = []
-riscv_sv39 = ["arch_riscv"]
-
-[dependencies]
-bitflags = "2.4"
diff --git a/lib/vspace/src/paging/arch/mod.rs b/lib/vspace/src/paging/arch/mod.rs
deleted file mode 100644
index 8f12c88..0000000
--- a/lib/vspace/src/paging/arch/mod.rs
+++ /dev/null
@@ -1,7 +0,0 @@
-pub use arch::*;
-
-// Arch Level
-#[cfg(feature = "arch_riscv")]
-#[path = "riscv/mod.rs"]
-#[allow(clippy::module_inception)]
-mod arch;