diff --git a/alioth/src/arch/x86_64/intr.rs b/alioth/src/arch/x86_64/intr.rs
index f0eb68d1..874ff324 100644
--- a/alioth/src/arch/x86_64/intr.rs
+++ b/alioth/src/arch/x86_64/intr.rs
@@ -29,16 +29,16 @@ consts! {
 }
 
 consts! {
-    pub struct TriggerMode(bool) {
-        EDGE = false;
-        LEVEL = true;
+    pub struct TriggerMode(u8) {
+        EDGE = 0;
+        LEVEL = 1;
     }
 }
 
 consts! {
-    pub struct DestinationMode(bool) {
-        PHYSICAL = false;
-        LOGICAL = true;
+    pub struct DestinationMode(u8) {
+        PHYSICAL = 0;
+        LOGICAL = 1;
     }
 }
 
@@ -46,7 +46,7 @@ bitfield! {
     #[derive(Copy, Clone, Default, PartialEq, Eq, Hash)]
     pub struct MsiAddrLo(u32);
     impl Debug;
-    pub mode, set_mode : 2;
+    pub u8, from into DestinationMode, mode, set_mode : 2, 2;
     pub redirection, set_redirection : 3;
     pub remappable, set_remappable : 4;
     pub u8, virt_dest_id_hi, set_virt_dest_id_hi : 11, 5;
@@ -67,7 +67,7 @@ bitfield! {
     impl Debug;
     impl new;
     pub u8, vector, set_vector : 7, 0;
-    pub u8, from into DeliveryMode, delivery_mode, set_delivery_mode : 11, 8;
+    pub u8, from into DeliveryMode, delivery_mode, set_delivery_mode : 10, 8;
     pub u8, level, set_level : 14;
-    pub trigger_mode, set_trigger_mode : 15;
+    pub u8, from into TriggerMode, trigger_mode, set_trigger_mode : 15, 15;
 }
diff --git a/alioth/src/arch/x86_64/ioapic.rs b/alioth/src/arch/x86_64/ioapic.rs
index 32999f3a..05a97f50 100644
--- a/alioth/src/arch/x86_64/ioapic.rs
+++ b/alioth/src/arch/x86_64/ioapic.rs
@@ -14,7 +14,7 @@
 
 use bitfield::bitfield;
 
-use crate::arch::x86_64::intr::DeliveryMode;
+use crate::arch::x86_64::intr::{DeliveryMode, DestinationMode, TriggerMode};
 
 pub const IOREGSEL: u64 = 0x00;
 pub const IOWIN: u64 = 0x10;
@@ -52,11 +52,11 @@ bitfield! {
     impl Debug;
     pub u8,	vector, set_vector : 7, 0;
     pub u8, from into DeliveryMode, delivery_mode, set_delivery_mode : 10, 8;
-    pub dest_mode, set_dest_mode : 11;
+    pub u8, from into DestinationMode, dest_mode, set_dest_mode : 11, 11;
     pub delivery_status, set_delivery_status : 12;
     pub riority, set_priority : 13;
     pub irr, set_irr : 14;
-    pub trigger_mode, set_trigger_mode : 15;
+    pub u8, from into TriggerMode, trigger_mode, set_trigger_mode : 15, 15;
     pub masked, set_masked : 16;
     pub u8, virt_dest_id_hi, set_virt_dest_id_hi : 55, 49;
     pub u8, dest_id, set_dest_id : 63, 56;
diff --git a/alioth/src/arch/x86_64/msr.rs b/alioth/src/arch/x86_64/msr.rs
index c21a6e38..1802bfd0 100644
--- a/alioth/src/arch/x86_64/msr.rs
+++ b/alioth/src/arch/x86_64/msr.rs
@@ -34,7 +34,6 @@ consts! {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct Efer(u64) {
         /// SYSCALL enable
         SCE = 1 << 0;
diff --git a/alioth/src/arch/x86_64/reg.rs b/alioth/src/arch/x86_64/reg.rs
index b72b1ff3..ffe3bbf3 100644
--- a/alioth/src/arch/x86_64/reg.rs
+++ b/alioth/src/arch/x86_64/reg.rs
@@ -58,7 +58,6 @@ bitflags! {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct Cr0(u64) {
         /// CarryProtected Mode Enable
         PE = 1 << 0;
@@ -86,7 +85,6 @@ bitflags! {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct Cr3(u64) {
         /// CarryPage-level write-through
         PWT = 1 << 3;
@@ -96,7 +94,6 @@ bitflags! {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct Cr4(u64) {
         /// CarryVirtual 8086 Mode Extensions
         VME = 1 << 0;
diff --git a/alioth/src/arch/x86_64/sev.rs b/alioth/src/arch/x86_64/sev.rs
index dc4c66a8..7d3cf4e9 100644
--- a/alioth/src/arch/x86_64/sev.rs
+++ b/alioth/src/arch/x86_64/sev.rs
@@ -89,7 +89,6 @@ consts! {
     /// AMD SEV-SNP launch update page type.
     ///
     /// From SEV SNP Firmware ABI Specification, Revision 1.55, Table 67.
-    #[derive(Default)]
     pub struct SnpPageType(u8) {
         /// A normal data page.
         NORMAL = 1;
diff --git a/alioth/src/arch/x86_64/tdx.rs b/alioth/src/arch/x86_64/tdx.rs
index d21fdf63..318f5743 100644
--- a/alioth/src/arch/x86_64/tdx.rs
+++ b/alioth/src/arch/x86_64/tdx.rs
@@ -12,12 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::bitflags;
-use serde::{Deserialize, Serialize};
 use serde_aco::Help;
 
+use crate::bitflags;
+
 bitflags! {
-    #[derive(Default, Serialize, Deserialize, Help)]
+    #[derive(Help)]
     pub struct TdAttr(u64) {
         DEBUG = 1 << 0;
         SEPT_VE_DISABLE = 1 << 28;
diff --git a/alioth/src/blk/qcow2.rs b/alioth/src/blk/qcow2.rs
index b4090eeb..10a17037 100644
--- a/alioth/src/blk/qcow2.rs
+++ b/alioth/src/blk/qcow2.rs
@@ -67,7 +67,6 @@ bitflags! {
 }
 
 consts! {
-    #[derive(Default, Immutable, KnownLayout, FromBytes, IntoBytes)]
     pub struct Qcow2Compression(u8) {
         DEFLATE = 0;
         ZSTD = 1;
diff --git a/alioth/src/device/ioapic.rs b/alioth/src/device/ioapic.rs
index c017596f..4925d2c1 100644
--- a/alioth/src/device/ioapic.rs
+++ b/alioth/src/device/ioapic.rs
@@ -60,11 +60,11 @@ impl<M: MsiSender> IoApic<M> {
             return Ok(());
         }
 
-        if entry.dest_mode() == DestinationMode::LOGICAL.raw() {
+        if entry.dest_mode() == DestinationMode::LOGICAL {
             log::warn!("IOAPIC: logical destination is not supported");
             return Ok(());
         }
-        if entry.trigger_mode() == TriggerMode::LEVEL.raw() {
+        if entry.trigger_mode() == TriggerMode::LEVEL {
             log::warn!("IOAPIC: level-triggered interrupts are not supported");
             return Ok(());
         }
diff --git a/alioth/src/device/pl011.rs b/alioth/src/device/pl011.rs
index a4a04e5b..e87a8edb 100644
--- a/alioth/src/device/pl011.rs
+++ b/alioth/src/device/pl011.rs
@@ -78,7 +78,6 @@ const PERIPH_ID: [u32; 4] = [0x11, 0x10, 0x14, 0x00];
 const PCELL_ID: [u32; 4] = [0x0d, 0xf0, 0x05, 0xb1];
 
 bitflags! {
-    #[derive(Default)]
     pub struct Flag(u16) {
         RI = 1 << 8;
         /// Transmit FIFO empty
@@ -97,7 +96,6 @@ bitflags! {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct Interrupt(u16) {
         /// Overrun error interrupt status.
         OERIS = 1 << 10;
diff --git a/alioth/src/device/pl031.rs b/alioth/src/device/pl031.rs
index 3ca2b416..dc5b5b5c 100644
--- a/alioth/src/device/pl031.rs
+++ b/alioth/src/device/pl031.rs
@@ -44,7 +44,6 @@ const PERIPH_ID: [u8; 4] = [0x31, 0x10, 0x04, 0x00];
 const PCELL_ID: [u8; 4] = [0x0d, 0xf0, 0x05, 0xb1];
 
 bitflags! {
-    #[derive(Default)]
     struct Interrupt(u32) {
         RTCINTR = 1 << 0;
     }
diff --git a/alioth/src/device/serial.rs b/alioth/src/device/serial.rs
index 7db516d5..78e18ca7 100644
--- a/alioth/src/device/serial.rs
+++ b/alioth/src/device/serial.rs
@@ -41,7 +41,6 @@ const SCRATCH_REGISTER: u64 = 0x7;
 
 // offset 0x1, Interrupt Enable Register (IER)
 bitflags! {
-    #[derive(Default)]
     pub struct InterruptEnable(u8) {
         MODEM_STATUS = 1 << 3;
         RECEIVER_LINE_STATUS = 1 << 2;
@@ -160,12 +159,6 @@ bitflags! {
     }
 }
 
-impl Default for LineStatus {
-    fn default() -> Self {
-        LineStatus::TX_EMPTY | LineStatus::TX_HOLDING_REGISTER_EMPTY
-    }
-}
-
 #[derive(Default, Debug)]
 struct SerialReg {
     interrupt_enable: InterruptEnable, // 0x1, Interrupt Enable Register (IER)
@@ -181,6 +174,15 @@ struct SerialReg {
     data: VecDeque<u8>,
 }
 
+impl SerialReg {
+    pub fn new() -> Self {
+        SerialReg {
+            line_status: LineStatus::TX_EMPTY | LineStatus::TX_HOLDING_REGISTER_EMPTY,
+            ..Default::default()
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct Serial<M: MsiSender, C> {
     name: Arc<str>,
@@ -338,7 +340,7 @@ where
     for<'a> &'a C: Read + Write,
 {
     pub fn new(base_port: u16, io_apci: Arc<IoApic<M>>, pin: u8, console: C) -> Result<Self> {
-        let reg = Arc::new(Mutex::new(SerialReg::default()));
+        let reg = Arc::new(Mutex::new(SerialReg::new()));
         let console = Arc::new(console);
         let name: Arc<str> = Arc::from(format!("serial_{base_port:#x}"));
         let uart_recv = SerialRecv {
diff --git a/alioth/src/firmware/acpi/bindings.rs b/alioth/src/firmware/acpi/bindings.rs
index 3ffbb741..f7e4fc6a 100644
--- a/alioth/src/firmware/acpi/bindings.rs
+++ b/alioth/src/firmware/acpi/bindings.rs
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 use bitfield::bitfield;
-use zerocopy::{FromBytes, Immutable, IntoBytes, KnownLayout};
+use zerocopy::{FromBytes, Immutable, IntoBytes};
 
 use crate::bitflags;
 
@@ -85,7 +85,6 @@ pub const FADT_MAJOR_VERSION: u8 = 6;
 pub const FADT_MINOR_VERSION: u8 = 4;
 
 bitflags! {
-    #[derive(Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
     pub struct AcpiFadtFlag(u32) {
         TMR_VAL_EXT = 1 << 8;
         RESET_REG_SUP = 1 << 10;
diff --git a/alioth/src/firmware/ovmf/ovmf_x86_64/sev.rs b/alioth/src/firmware/ovmf/ovmf_x86_64/sev.rs
index fa5ed602..bf3457c0 100644
--- a/alioth/src/firmware/ovmf/ovmf_x86_64/sev.rs
+++ b/alioth/src/firmware/ovmf/ovmf_x86_64/sev.rs
@@ -37,7 +37,6 @@ pub struct SevMetaData {
 }
 
 consts! {
-    #[derive(KnownLayout, Immutable, FromBytes, IntoBytes)]
     pub struct SevDescType(u32) {
         SNP_DESC_MEM = 1;
         SNP_SECRETS = 2;
diff --git a/alioth/src/firmware/ovmf/ovmf_x86_64/tdx.rs b/alioth/src/firmware/ovmf/ovmf_x86_64/tdx.rs
index 12520525..31cb145f 100644
--- a/alioth/src/firmware/ovmf/ovmf_x86_64/tdx.rs
+++ b/alioth/src/firmware/ovmf/ovmf_x86_64/tdx.rs
@@ -43,7 +43,6 @@ pub struct TdvfMetadata {
 }
 
 consts! {
-    #[derive(Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
     pub struct TdvfSectionType(u32) {
         BFV = 0;
         CFV = 1;
@@ -53,7 +52,6 @@ consts! {
 }
 
 bitflags! {
-    #[derive(Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
     pub struct TdvfSectionAttr(u32) {
         MR_EXTEND = 1 << 0;
         PAGE_AUG = 1 << 1;
diff --git a/alioth/src/firmware/uefi/uefi.rs b/alioth/src/firmware/uefi/uefi.rs
index 90afd189..320ead07 100644
--- a/alioth/src/firmware/uefi/uefi.rs
+++ b/alioth/src/firmware/uefi/uefi.rs
@@ -17,7 +17,6 @@ use zerocopy::{FromBytes, Immutable, IntoBytes, KnownLayout};
 use crate::{bitflags, consts};
 
 consts! {
-    #[derive(Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
     pub struct HobType(u16) {
         HANDOFF = 0x0001;
         RESOURCE_DESCRIPTOR = 0x0003;
@@ -49,7 +48,6 @@ pub struct HobHandoffInfoTable {
 }
 
 consts! {
-    #[derive(Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
     pub struct HobResourceType(u32) {
         SYSTEM_MEMORY = 0x00000000;
         MEMORY_UNACCEPTED = 0x00000007;
@@ -57,7 +55,6 @@ consts! {
 }
 
 bitflags! {
-    #[derive(Default, KnownLayout, Immutable, FromBytes, IntoBytes)]
     pub struct ResourceAttr(u32) {
         PRESENT =  1 << 0;
         INIT =  1 << 1;
diff --git a/alioth/src/fuse/bindings.rs b/alioth/src/fuse/bindings.rs
index 0317437e..7a878966 100644
--- a/alioth/src/fuse/bindings.rs
+++ b/alioth/src/fuse/bindings.rs
@@ -262,7 +262,6 @@ pub struct FuseFileLock {
 }
 
 consts! {
-    #[derive(FromBytes, Immutable, IntoBytes)]
     pub struct FuseOpcode(u32) {
         LOOKUP = 1;
         FORGET = 2;
@@ -724,7 +723,6 @@ pub struct FuseOutHeader {
 }
 
 consts! {
-    #[derive(FromBytes, KnownLayout, Immutable, IntoBytes)]
     pub struct FuseDirentType(u32) {
         UNKNOWN = 0x0;
         FIFO = 0x1;
@@ -901,7 +899,6 @@ pub struct FuseSecctxHeader {
 }
 
 consts! {
-    #[derive(Default, FromBytes, KnownLayout, Immutable, IntoBytes)]
     pub struct FuseExtType(u32) {
         MAX_NR_SECCTX = 31;
         EXT_GROUPS = 32;
diff --git a/alioth/src/pci/cap.rs b/alioth/src/pci/cap.rs
index 7bb272af..eb38ad3f 100644
--- a/alioth/src/pci/cap.rs
+++ b/alioth/src/pci/cap.rs
@@ -31,7 +31,6 @@ use crate::utils::truncate_u64;
 use crate::{align_up, consts, impl_mmio_for_zerocopy, mask_bits, mem};
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, IntoBytes, KnownLayout)]
     pub struct PciCapId(u8) {
         MSI = 0x05;
         VENDOR = 0x09;
diff --git a/alioth/src/pci/config.rs b/alioth/src/pci/config.rs
index d3e6b517..9f90d2b5 100644
--- a/alioth/src/pci/config.rs
+++ b/alioth/src/pci/config.rs
@@ -53,7 +53,6 @@ impl SlotBackend for Box<dyn PciConfigArea> {
 }
 
 bitflags! {
-    #[derive(Default, FromBytes, Immutable, KnownLayout, IntoBytes)]
     pub struct Command(u16) {
         INTX_DISABLE = 1 << 10;
         SERR = 1 << 8;
@@ -71,7 +70,6 @@ bitflags! {
 }
 
 bitflags! {
-    #[derive(Default, FromBytes, Immutable, KnownLayout, IntoBytes)]
     pub struct Status(u16) {
         PARITY_ERR = 1 << 15;
         SYSTEM_ERR = 1 << 14;
@@ -92,7 +90,6 @@ bitflags! {
 }
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, KnownLayout, IntoBytes)]
     pub struct HeaderType(u8) {
         DEVICE = 0;
         BRIDGE = 1;
diff --git a/alioth/src/sys/linux/kvm.rs b/alioth/src/sys/linux/kvm.rs
index 680efb1e..b8e0e42f 100644
--- a/alioth/src/sys/linux/kvm.rs
+++ b/alioth/src/sys/linux/kvm.rs
@@ -44,7 +44,6 @@ pub struct KvmVmType(#[allow(dead_code)] pub u64);
 pub const KVM_MAX_CPUID_ENTRIES: usize = 256;
 
 bitflags! {
-    #[derive(Default)]
     pub struct KvmCpuid2Flag(u32) {
         SIGNIFCANT_INDEX = 1 << 0;
     }
@@ -115,7 +114,6 @@ pub struct KvmMsrs<const N: usize> {
 pub const MAX_IO_MSRS: usize = 256;
 
 bitflags! {
-    #[derive(Default)]
     pub struct KvmMemFlag(u32) {
         LOG_DIRTY_PAGES = 1 << 0;
         READONLY = 1 << 1;
@@ -148,7 +146,6 @@ pub struct KvmUserspaceMemoryRegion2 {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct KvmMemoryAttribute(u64) {
         PRIVATE = 1 << 3;
     }
@@ -383,7 +380,6 @@ pub union KvmSyncRegsBlock {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct KvmIrqfdFlag(u32) {
         DEASSIGN = 1 << 0;
         RESAMPLE = 1 << 1;
@@ -484,7 +480,6 @@ impl<const N: usize> Debug for KvmIrqRouting<N> {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct KvmMsiFlag(u32) {
         VALID_DEVID = 1 << 0;
     }
@@ -532,7 +527,6 @@ bitflags! {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct KvmIoEventFdFlag(u32) {
         DATA_MATCH = 1 << 0;
         PIO = 1 << 1;
diff --git a/alioth/src/sys/linux/tdx.rs b/alioth/src/sys/linux/tdx.rs
index 476ceaa9..49b07190 100644
--- a/alioth/src/sys/linux/tdx.rs
+++ b/alioth/src/sys/linux/tdx.rs
@@ -17,7 +17,6 @@ use crate::sys::kvm::{KVM_MAX_CPUID_ENTRIES, KvmCpuid2};
 use crate::{bitflags, consts};
 
 consts! {
-    #[derive(Default)]
     pub struct KvmTdxCmdId(u32) {
         CAPABILITIES = 0;
         INIT_VM = 1;
diff --git a/alioth/src/sys/linux/vfio.rs b/alioth/src/sys/linux/vfio.rs
index 3926dc84..ea3e7c1d 100644
--- a/alioth/src/sys/linux/vfio.rs
+++ b/alioth/src/sys/linux/vfio.rs
@@ -30,7 +30,6 @@ pub struct VfioInfoCapHeader {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct VfioDeviceInfoFlag(u32) {
         RESET = 1 << 0;
         PCI = 1 << 1;
@@ -56,7 +55,6 @@ pub struct VfioDeviceInfo {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct VfioRegionInfoFlag(u32) {
         READ = 1 << 0;
         WRITE = 1 << 1;
@@ -91,14 +89,12 @@ pub struct VfioRegionInfo {
 }
 
 consts! {
-    #[derive(Default)]
     pub struct VfioRegionInfoCap(u16) {
         MSIX_MAPPABLE = 3;
     }
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct VfioIrqInfoFlag(u32) {
         EVENTFD = 1 << 0;
         MASKABLE = 1 << 1;
@@ -108,7 +104,6 @@ bitflags! {
 }
 
 consts! {
-    #[derive(Default)]
     pub struct VfioPciIrq(u32) {
         INTX = 0;
         MSI = 1;
@@ -196,7 +191,6 @@ pub struct IommuIoasAlloc {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct IommuIoasMapFlag(u32) {
         FIXED_IOVA = 1 << 0;
         WRITEABLE = 1 << 1;
@@ -226,7 +220,6 @@ pub struct IommuIoasUnmap {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct VfioDmaMapFlag(u32) {
         READ = 1 << 0;
         WRITE = 1 << 1;
@@ -245,7 +238,6 @@ pub struct VfioIommuType1DmaMap {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct VfioDmaUnmapFlag(u32) {
         GET_DIRTY_BITMAP = 1 << 0;
         ALL = 1 << 1;
diff --git a/alioth/src/sys/macos/block.rs b/alioth/src/sys/macos/block.rs
index e75f0690..45807c56 100644
--- a/alioth/src/sys/macos/block.rs
+++ b/alioth/src/sys/macos/block.rs
@@ -25,7 +25,6 @@ pub struct BlockDescriptor {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct BlockFlag(c_int) {
         HAS_STRET = 1 << 29;
     }
diff --git a/alioth/src/sys/macos/hvf.rs b/alioth/src/sys/macos/hvf.rs
index dc63d9c6..c1b3232f 100644
--- a/alioth/src/sys/macos/hvf.rs
+++ b/alioth/src/sys/macos/hvf.rs
@@ -58,7 +58,6 @@ consts! {
 }
 
 consts! {
-    #[derive(Default)]
     pub struct HvExitReason(u32) {
         CANCEL = 0;
         EXCEPTION = 1;
diff --git a/alioth/src/utils/utils.rs b/alioth/src/utils/utils.rs
index f72adcdd..e13245e4 100644
--- a/alioth/src/utils/utils.rs
+++ b/alioth/src/utils/utils.rs
@@ -127,7 +127,20 @@ macro_rules! consts {
         }
     ) => {
         #[repr(transparent)]
-        #[derive(PartialEq, Eq, Copy, Clone)]
+        #[derive(
+            Copy,
+            Clone,
+            Default,
+            PartialEq,
+            Eq,
+            Hash,
+            ::zerocopy::KnownLayout,
+            ::zerocopy::Immutable,
+            ::zerocopy::FromBytes,
+            ::zerocopy::IntoBytes,
+            ::serde::Serialize,
+            ::serde::Deserialize,
+        )]
         $(#[$attr])*
         $vs struct $EnumName($TyName);
 
@@ -194,7 +207,20 @@ macro_rules! bitflags {
         }
     ) => {
         #[repr(transparent)]
-        #[derive(PartialEq, Eq, Copy, Clone, Hash)]
+        #[derive(
+            Copy,
+            Clone,
+            Default,
+            PartialEq,
+            Eq,
+            Hash,
+            ::zerocopy::KnownLayout,
+            ::zerocopy::Immutable,
+            ::zerocopy::FromBytes,
+            ::zerocopy::IntoBytes,
+            ::serde::Serialize,
+            ::serde::Deserialize,
+        )]
         $(#[$attr])*
         $vs struct $FlagTy($TyName);
 
diff --git a/alioth/src/virtio/dev/blk.rs b/alioth/src/virtio/dev/blk.rs
index 79022458..460c0c2c 100644
--- a/alioth/src/virtio/dev/blk.rs
+++ b/alioth/src/virtio/dev/blk.rs
@@ -48,7 +48,6 @@ use crate::virtio::{DeviceId, FEATURE_BUILT_IN, IrqSender, Result, error};
 use crate::{bitflags, consts, impl_mmio_for_zerocopy};
 
 consts! {
-    #[derive(FromBytes)]
     pub struct RequestType(u32) {
         IN = 0;
         OUT = 1;
@@ -62,7 +61,6 @@ consts! {
 }
 
 consts! {
-    #[derive(FromBytes)]
     pub struct Status(u8) {
         OK = 0;
         IOERR = 1;
diff --git a/alioth/src/virtio/dev/fs/fs.rs b/alioth/src/virtio/dev/fs/fs.rs
index 4005fa07..649310af 100644
--- a/alioth/src/virtio/dev/fs/fs.rs
+++ b/alioth/src/virtio/dev/fs/fs.rs
@@ -44,6 +44,8 @@ use crate::virtio::worker::mio::{ActiveMio, Mio, VirtioMio};
 use crate::virtio::{DeviceId, FEATURE_BUILT_IN, IrqSender};
 use crate::{bitflags, ffi, impl_mmio_for_zerocopy};
 
+pub const DAX_SHMEM_ID: u8 = 0;
+
 impl DaxRegion for ArcMemPages {
     fn map(
         &self,
diff --git a/alioth/src/virtio/dev/fs/vu.rs b/alioth/src/virtio/dev/fs/vu.rs
index a9945fef..e4f51b6f 100644
--- a/alioth/src/virtio/dev/fs/vu.rs
+++ b/alioth/src/virtio/dev/fs/vu.rs
@@ -14,7 +14,6 @@
 
 use std::fs::File;
 use std::io::ErrorKind;
-use std::iter::zip;
 use std::mem::size_of_val;
 use std::os::fd::{AsFd, AsRawFd};
 use std::path::Path;
@@ -37,10 +36,12 @@ use crate::hv::IoeventFd;
 use crate::mem::mapped::{ArcMemPages, RamBus};
 use crate::mem::{LayoutChanged, MemRegion, MemRegionType};
 use crate::sync::notifier::Notifier;
-use crate::virtio::dev::fs::{FsConfig, FsFeature};
+use crate::virtio::dev::fs::{DAX_SHMEM_ID, FsConfig, FsFeature};
 use crate::virtio::dev::{DevParam, Virtio, WakeEvent};
 use crate::virtio::queue::{QueueReg, VirtQueue};
-use crate::virtio::vu::bindings::{DeviceConfig, FsMap, VuBackMsg, VuFeature};
+use crate::virtio::vu::bindings::{
+    DeviceConfig, VhostUserMmap, VhostUserMmapFlag, VuBackMsg, VuFeature,
+};
 use crate::virtio::vu::conn::VuChannel;
 use crate::virtio::vu::frontend::VuFrontend;
 use crate::virtio::vu::{Error, error as vu_error};
@@ -59,7 +60,7 @@ impl VuFs {
     pub fn new(param: VuFsParam, name: impl Into<Arc<str>>) -> Result<Self> {
         let mut extra_features = VuFeature::empty();
         if param.dax_window > 0 {
-            extra_features |= VuFeature::BACKEND_REQ | VuFeature::BACKEND_SEND_FD
+            extra_features |= VuFeature::BACKEND_REQ | VuFeature::BACKEND_SEND_FD | VuFeature::SHMEM
         };
         if param.tag.is_none() {
             extra_features |= VuFeature::CONFIG;
@@ -234,66 +235,67 @@ impl VirtioMio for VuFs {
             .fail()?;
         };
         loop {
-            let mut fds = [const { None }; 8];
+            let mut fds = [None];
             let msg = channel.recv_msg(&mut fds);
             let (request, size) = match msg {
                 Ok(m) => (m.request, m.size),
                 Err(Error::System { error, .. }) if error.kind() == ErrorKind::WouldBlock => break,
                 Err(e) => return Err(e)?,
             };
-            let fs_map: FsMap = channel.recv_payload()?;
+            let payload: VhostUserMmap = channel.recv_payload()?;
 
-            if size as usize != size_of_val(&fs_map) {
+            if size as usize != size_of_val(&payload) {
                 return vu_error::PayloadSize {
-                    want: size_of_val(&fs_map),
+                    want: size_of_val(&payload),
                     got: size,
                 }
                 .fail()?;
             }
             match VuBackMsg::from(request) {
-                VuBackMsg::SHARED_OBJECT_ADD => {
-                    for (index, fd) in fds.iter().enumerate() {
-                        let Some(fd) = fd else {
-                            break;
-                        };
-                        let raw_fd = fd.as_raw_fd();
-                        let map_addr = dax_region.addr() + fs_map.cache_offset[index] as usize;
-                        log::trace!(
-                            "{}: mapping fd {raw_fd} to offset {:#x}",
-                            self.name(),
-                            fs_map.cache_offset[index]
-                        );
-                        ffi!(
-                            unsafe {
-                                mmap(
-                                    map_addr as _,
-                                    fs_map.len[index] as _,
-                                    fs_map.flags[index] as _,
-                                    MAP_SHARED | MAP_FIXED,
-                                    raw_fd,
-                                    fs_map.fd_offset[index] as _,
-                                )
-                            },
-                            MAP_FAILED
-                        )?;
-                    }
+                VuBackMsg::SHMEM_MAP => {
+                    let [Some(fd)] = fds else {
+                        return vu_error::MissingFd { req: request }.fail()?;
+                    };
+                    let shm_offset = payload.shm_offset;
+                    let map_addr = dax_region.addr() + shm_offset as usize;
+                    let prot = if payload.flags.contains(VhostUserMmapFlag::RW) {
+                        libc::PROT_READ | libc::PROT_WRITE
+                    } else {
+                        libc::PROT_READ
+                    };
+                    log::trace!(
+                        "{}: mapping fd {} to offset {shm_offset:#x}, size {:#x}",
+                        self.name(),
+                        fd.as_raw_fd(),
+                        payload.len,
+                    );
+                    ffi!(
+                        unsafe {
+                            mmap(
+                                map_addr as _,
+                                payload.len as _,
+                                prot,
+                                MAP_SHARED | MAP_FIXED,
+                                fd.as_raw_fd(),
+                                payload.fd_offset as _,
+                            )
+                        },
+                        MAP_FAILED
+                    )?;
                 }
-                VuBackMsg::SHARED_OBJECT_REMOVE => {
-                    for (len, offset) in zip(fs_map.len, fs_map.cache_offset) {
-                        if len == 0 {
-                            continue;
-                        }
-                        log::trace!(
-                            "{}: unmapping offset {offset:#x}, size {len:#x}",
-                            self.name()
-                        );
-                        let map_addr = dax_region.addr() + offset as usize;
-                        let flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED;
-                        ffi!(
-                            unsafe { mmap(map_addr as _, len as _, PROT_NONE, flags, -1, 0) },
-                            MAP_FAILED
-                        )?;
-                    }
+                VuBackMsg::SHMEM_UNMAP => {
+                    let shm_offset = payload.shm_offset;
+                    let len = payload.len;
+                    log::trace!(
+                        "{}: unmapping offset {shm_offset:#x}, size {len:#x}",
+                        self.name(),
+                    );
+                    let map_addr = dax_region.addr() + shm_offset as usize;
+                    let flags = MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED;
+                    ffi!(
+                        unsafe { mmap(map_addr as _, len as _, PROT_NONE, flags, -1, 0) },
+                        MAP_FAILED
+                    )?;
                 }
                 _ => unimplemented!("{}: unknown request {request:#x}", self.name()),
             }
@@ -334,32 +336,34 @@ impl DaxRegion for VuDaxRegion {
         len: u64,
         flag: FuseSetupmappingFlag,
     ) -> fuse::Result<()> {
-        let mut fs_map = FsMap::new_zeroed();
-        fs_map.fd_offset[0] = f_offset;
-        fs_map.cache_offset[0] = m_offset;
-
-        let mut prot = 0;
-        if flag.contains(FuseSetupmappingFlag::READ) {
-            prot |= libc::PROT_READ;
+        let flags = if flag.contains(FuseSetupmappingFlag::WRITE) {
+            VhostUserMmapFlag::RW
+        } else {
+            VhostUserMmapFlag::empty()
         };
-        if flag.contains(FuseSetupmappingFlag::WRITE) {
-            prot |= libc::PROT_WRITE;
-        }
-        fs_map.flags[0] = prot as _;
 
-        fs_map.len[0] = len;
-        let fds = [fd.as_fd()];
+        let payload = VhostUserMmap {
+            shmid: DAX_SHMEM_ID,
+            fd_offset: f_offset,
+            shm_offset: m_offset,
+            len,
+            flags,
+            ..Default::default()
+        };
         self.channel
-            .fs_map(&fs_map, &fds)
+            .shmem_map(&payload, fd.as_fd())
             .box_trace(fuse::error::DaxMapping)
     }
 
     fn unmap(&self, m_offset: u64, len: u64) -> fuse::Result<()> {
-        let mut fs_map = FsMap::new_zeroed();
-        fs_map.cache_offset[0] = m_offset;
-        fs_map.len[0] = len;
+        let payload = VhostUserMmap {
+            shmid: DAX_SHMEM_ID,
+            shm_offset: m_offset,
+            len,
+            ..Default::default()
+        };
         self.channel
-            .fs_unmap(&fs_map)
+            .shmem_unmap(&payload)
             .box_trace(fuse::error::DaxMapping)
     }
 }
diff --git a/alioth/src/virtio/dev/net/net.rs b/alioth/src/virtio/dev/net/net.rs
index 9aeacd4d..1b626f0a 100644
--- a/alioth/src/virtio/dev/net/net.rs
+++ b/alioth/src/virtio/dev/net/net.rs
@@ -41,7 +41,6 @@ pub struct NetConfig {
 impl_mmio_for_zerocopy!(NetConfig);
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, IntoBytes)]
     pub struct CtrlAck(u8) {
         OK = 0;
         ERR = 1;
@@ -49,14 +48,12 @@ consts! {
 }
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, IntoBytes)]
     pub struct CtrlClass(u8) {
         MQ = 4;
     }
 }
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, IntoBytes)]
     pub struct CtrlMq(u8) {
         VQ_PARIS_SET = 0;
     }
diff --git a/alioth/src/virtio/dev/vsock/vsock.rs b/alioth/src/virtio/dev/vsock/vsock.rs
index 783609b6..dedf3aaf 100644
--- a/alioth/src/virtio/dev/vsock/vsock.rs
+++ b/alioth/src/virtio/dev/vsock/vsock.rs
@@ -27,7 +27,6 @@ pub use self::uds_vsock::{UdsVsock, UdsVsockParam};
 pub use self::vhost_vsock::{VhostVsock, VhostVsockParam};
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, IntoBytes)]
     pub struct VsockVirtq(u16) {
         RX = 0;
         TX = 1;
@@ -54,7 +53,6 @@ bitflags! {
 }
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, IntoBytes)]
     pub struct VsockOp(u16) {
         INVALID = 0;
         REQUEST = 1;
@@ -68,7 +66,6 @@ consts! {
 }
 
 consts! {
-    #[derive(Default, FromBytes, Immutable, IntoBytes)]
     pub struct VsockType(u16) {
         STREAM = 1;
         SEQPACKET = 2;
diff --git a/alioth/src/virtio/pci.rs b/alioth/src/virtio/pci.rs
index 4a9c8375..13619d5b 100644
--- a/alioth/src/virtio/pci.rs
+++ b/alioth/src/virtio/pci.rs
@@ -585,7 +585,6 @@ fn get_class(id: DeviceId) -> (u8, u8) {
 }
 
 consts! {
-    #[derive(Default, FromZeros, Immutable, IntoBytes)]
     pub struct VirtioPciCfg(u8) {
         COMMON = 1;
         NOTIFY = 2;
diff --git a/alioth/src/virtio/virtio.rs b/alioth/src/virtio/virtio.rs
index 08f5a0be..bbbbf08b 100644
--- a/alioth/src/virtio/virtio.rs
+++ b/alioth/src/virtio/virtio.rs
@@ -114,7 +114,6 @@ consts! {
 }
 
 bitflags! {
-    #[derive(Default)]
     pub struct DevStatus(u8) {
         ACK = 1 << 0;
         DRIVER = 1 << 1;
diff --git a/alioth/src/virtio/vu/backend.rs b/alioth/src/virtio/vu/backend.rs
index 0a5c744f..ea753672 100644
--- a/alioth/src/virtio/vu/backend.rs
+++ b/alioth/src/virtio/vu/backend.rs
@@ -271,7 +271,8 @@ impl VuBackend {
                     | VuFeature::BACKEND_REQ
                     | VuFeature::BACKEND_SEND_FD
                     | VuFeature::CONFIG
-                    | VuFeature::STATUS;
+                    | VuFeature::STATUS
+                    | VuFeature::SHMEM;
                 self.session.reply(req, &feature.bits(), &[])?;
                 msg.flag.set_need_reply(false);
                 log::debug!("{name}: get protocol feature: {feature:x?}");
diff --git a/alioth/src/virtio/vu/bindings.rs b/alioth/src/virtio/vu/bindings.rs
index 65a57c05..4bf744cc 100644
--- a/alioth/src/virtio/vu/bindings.rs
+++ b/alioth/src/virtio/vu/bindings.rs
@@ -39,6 +39,7 @@ bitflags! {
         XEN_MMAP = 1 << 17;
         SHARED_OBJECT = 1 << 18;
         DEVICE_STATE = 1 << 19;
+        SHMEM = 1 << 21;
     }
 }
 
@@ -89,12 +90,6 @@ consts! {
     }
 }
 
-consts! {
-    pub struct VuFrontMsgSize((u32, usize)) {
-        GET_FEATURES = (0, size_of::<u64>());
-    }
-}
-
 consts! {
     pub struct VuBackMsg(u32) {
         IOTLB_MSG = 1;
@@ -105,6 +100,8 @@ consts! {
         SHARED_OBJECT_ADD = 6;
         SHARED_OBJECT_REMOVE = 7;
         SHARED_OBJECT_LOOKUP = 8;
+        SHMEM_MAP = 9;
+        SHMEM_UNMAP = 10;
     }
 }
 
@@ -184,15 +181,6 @@ pub struct DeviceConfig {
     pub flags: u32,
 }
 
-#[derive(Debug, Clone, FromBytes, Immutable, IntoBytes, KnownLayout)]
-#[repr(C)]
-pub struct FsMap {
-    pub fd_offset: [u64; 8],
-    pub cache_offset: [u64; 8],
-    pub len: [u64; 8],
-    pub flags: [u64; 8],
-}
-
 #[derive(Debug, IntoBytes, FromBytes, Immutable, KnownLayout)]
 #[repr(C)]
 pub struct Message {
@@ -200,3 +188,20 @@ pub struct Message {
     pub flag: MessageFlag,
     pub size: u32,
 }
+
+bitflags! {
+    pub struct VhostUserMmapFlag(u64) {
+        RW = 1 << 0;
+    }
+}
+
+#[derive(Debug, Clone, Default, FromBytes, Immutable, IntoBytes, KnownLayout)]
+#[repr(C)]
+pub struct VhostUserMmap {
+    pub shmid: u8,
+    pub padding: [u8; 7],
+    pub fd_offset: u64,
+    pub shm_offset: u64,
+    pub len: u64,
+    pub flags: VhostUserMmapFlag,
+}
diff --git a/alioth/src/virtio/vu/conn.rs b/alioth/src/virtio/vu/conn.rs
index 7eb76095..7a3b342d 100644
--- a/alioth/src/virtio/vu/conn.rs
+++ b/alioth/src/virtio/vu/conn.rs
@@ -23,8 +23,8 @@ use zerocopy::{FromBytes, FromZeros, Immutable, IntoBytes};
 use crate::ffi;
 use crate::utils::uds::{recv_msg_with_fds, send_msg_with_fds};
 use crate::virtio::vu::bindings::{
-    DeviceConfig, FsMap, MAX_CONFIG_SIZE, MemorySingleRegion, Message, MessageFlag, VirtqAddr,
-    VirtqState, VuBackMsg, VuFrontMsg,
+    DeviceConfig, MAX_CONFIG_SIZE, MemorySingleRegion, Message, MessageFlag, VhostUserMmap,
+    VirtqAddr, VirtqState, VuBackMsg, VuFrontMsg,
 };
 use crate::virtio::vu::{Result, error};
 
@@ -363,11 +363,11 @@ impl VuChannel {
         send(&self.conn, req.raw(), payload, &[], &mut [], fds)
     }
 
-    pub fn fs_map(&self, payload: &FsMap, fds: &[BorrowedFd]) -> Result<()> {
-        self.send(VuBackMsg::SHARED_OBJECT_ADD, payload, fds)
+    pub fn shmem_map(&self, payload: &VhostUserMmap, fd: BorrowedFd) -> Result<()> {
+        self.send(VuBackMsg::SHMEM_MAP, payload, &[fd])
     }
 
-    pub fn fs_unmap(&self, payload: &FsMap) -> Result<()> {
-        self.send(VuBackMsg::SHARED_OBJECT_REMOVE, payload, &[])
+    pub fn shmem_unmap(&self, payload: &VhostUserMmap) -> Result<()> {
+        self.send(VuBackMsg::SHMEM_UNMAP, payload, &[])
     }
 }