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Directly implement AsBytes trait for Generic structs [experiemntal].
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Attempts to completely remove the AsSliceU8 trait by directly
implementing AsBytes for generic structs because of lack of support for
generics using derive.

Fixes #692.

Signed-off-by: Joanne Chen <[email protected]>
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Joanne Chen committed Apr 21, 2023
1 parent 5934f22 commit eb56619
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Showing 7 changed files with 75 additions and 97 deletions.
8 changes: 4 additions & 4 deletions Cargo.lock
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2 changes: 1 addition & 1 deletion Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,7 @@ lock_api = "0.4"
num = { version = "0.4", default-features = false }
num-traits = { version = "0.2", default-features = false }
num-derive = "0.3"
zerocopy = "0.6"
zerocopy = "0.7.0-alpha.3"

[dependencies.smoltcp]
version = "0.9"
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5 changes: 3 additions & 2 deletions src/drivers/fs/virtio_fs.rs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
use alloc::rc::Rc;
use alloc::string::{String, ToString};
use alloc::vec::Vec;
use zerocopy::AsBytes;

use self::constants::{FeatureSet, Features};
use crate::config::VIRTIO_MAX_QUEUE_SIZE;
Expand All @@ -12,7 +13,7 @@ use crate::drivers::virtio::transport::mmio::{ComCfg, IsrStatus, NotifCfg};
#[cfg(feature = "pci")]
use crate::drivers::virtio::transport::pci::{ComCfg, IsrStatus, NotifCfg};
use crate::drivers::virtio::virtqueue::{
AsSliceU8, BuffSpec, BufferToken, Bytes, Virtq, VqIndex, VqSize, VqType,
BuffSpec, BufferToken, Bytes, Virtq, VqIndex, VqSize, VqType,
};
use crate::fs::fuse::{self, FuseInterface};

Expand Down Expand Up @@ -168,7 +169,7 @@ impl FuseInterface for VirtioFsDriver {
self.ready_queue.push(tkn);

if let Some(response) = response {
rsp.as_slice_u8_mut()[..response.len()].copy_from_slice(response.as_ref());
rsp.as_bytes_mut()[..response.len()].copy_from_slice(response.as_ref());
}
}
}
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56 changes: 7 additions & 49 deletions src/drivers/virtio/virtqueue/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -142,8 +142,8 @@ impl Virtq {
///
/// Structures provided to the Queue must pass this test, otherwise the queue
/// currently panics.
pub fn check_bounds<T: AsSliceU8>(data: &T) -> bool {
let slice = data.as_slice_u8();
pub fn check_bounds<T: AsBytes>(data: &T) -> bool {
let slice = data.as_bytes();

let start_virt = (&slice[0] as *const u8) as usize;
let end_virt = (&slice[slice.len() - 1] as *const u8) as usize;
Expand Down Expand Up @@ -443,7 +443,7 @@ impl Virtq {
/// ```
/// Then he must split the structure after the send part and provide the respective part via the send argument and the respective other
/// part via the recv argument.
pub fn prep_transfer_from_raw<T: AsSliceU8 + 'static, K: AsSliceU8 + 'static>(
pub fn prep_transfer_from_raw<T: AsBytes + 'static, K: AsBytes + 'static>(
&self,
rc_self: Rc<Virtq>,
send: Option<(*mut T, BuffSpec<'_>)>,
Expand Down Expand Up @@ -519,48 +519,6 @@ impl Virtq {
}
}

/// The trait needs to be implemented on structures which are to be used via the `prep_transfer()` function of virtqueues and for
/// structures which are to be used to write data into buffers of a [BufferToken](BufferToken) via `BufferToken.write()` or
/// `BufferToken.write_seq()`.
///
/// **INFO:*
/// The trait provides a decent default implementation. Please look at the code for details.
/// The provided default implementation computes the size of the given structure via `core::mem::size_of_val(&self)`
/// and then casts the given `*const Self` pointer of the structure into an `*const u8`.
///
/// Users must be really careful, and check, whether the memory representation of the given structure equals
/// the representation the device expects. It is advised to only use `#[repr(C)]` and to check the output
/// of `as_slice_u8` and `as_slice_u8_mut`.
pub trait AsSliceU8 {
/// Retruns the size of the structure
///
/// In case of an unsized structure, the function should returns
/// the exact value of the structure.
fn len(&self) -> usize {
core::mem::size_of_val(self)
}

/// Returns a slice of the given structure.
///
/// ** WARN:**
/// * The slice must be little endian coded in order to be understood by the device
/// * The slice must serialize the actual structure the device expects, as the queue will use
/// the addresses of the slice in order to refer to the structure.
fn as_slice_u8(&self) -> &[u8] {
unsafe { core::slice::from_raw_parts((self as *const _) as *const u8, self.len()) }
}

/// Returns a mutable slice of the given structure.
///
/// ** WARN:**
/// * The slice must be little endian coded in order to be understood by the device
/// * The slice must serialize the actual structure the device expects, as the queue will use
/// the addresses of the slice in order to refer to the structure.
fn as_slice_u8_mut(&mut self) -> &mut [u8] {
unsafe { core::slice::from_raw_parts_mut((self as *const _) as *mut u8, self.len()) }
}
}

/// The [Transfer](Transfer) will be received when a [TransferToken](TransferToken) is dispatched via `TransferToken.dispatch()` or
/// via `TransferToken.dispatch_blocking()`.
///
Expand Down Expand Up @@ -1605,18 +1563,18 @@ impl BufferToken {
/// descriptors.
/// The `write()` function does NOT take into account the distinct descriptors of a buffer but treats the buffer as a single continuous
/// memory element and as a result writes `T` or `H` as a slice of bytes into this memory.
pub fn write<K: AsSliceU8 + ?Sized, H: AsSliceU8 + ?Sized>(
pub fn write<K: AsBytes + ?Sized, H: AsBytes + ?Sized>(
mut self,
send: Option<&K>,
recv: Option<&H>,
) -> Result<TransferToken, VirtqError> {
if let Some(data) = send {
match self.send_buff.as_mut() {
Some(buff) => {
if buff.len() < data.as_slice_u8().len() {
if buff.len() < data.as_bytes().len() {
return Err(VirtqError::WriteToLarge(self));
} else {
let data_slc = data.as_slice_u8();
let data_slc = data.as_bytes();
let mut from = 0usize;

for i in 0..buff.num_descr() {
Expand All @@ -1640,7 +1598,7 @@ impl BufferToken {
if let Some(data) = recv {
match self.recv_buff.as_mut() {
Some(buff) => {
let data_slc = data.as_slice_u8();
let data_slc = data.as_bytes();

if buff.len() < data_slc.len() {
return Err(VirtqError::WriteToLarge(self));
Expand Down
37 changes: 19 additions & 18 deletions src/drivers/virtio/virtqueue/packed.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@ use alloc::vec::Vec;
use core::cell::RefCell;
use core::ptr;
use core::sync::atomic::{fence, Ordering};
use zerocopy::AsBytes;

use align_address::Align;

Expand All @@ -20,7 +21,7 @@ use super::super::transport::mmio::{ComCfg, NotifCfg, NotifCtrl};
use super::super::transport::pci::{ComCfg, NotifCfg, NotifCtrl};
use super::error::VirtqError;
use super::{
AsSliceU8, BuffSpec, Buffer, BufferToken, Bytes, DescrFlags, MemDescr, MemPool, Pinned,
BuffSpec, Buffer, BufferToken, Bytes, DescrFlags, MemDescr, MemPool, Pinned,
Transfer, TransferState, TransferToken, Virtq, VqIndex, VqSize,
};
use crate::arch::mm::paging::{BasePageSize, PageSize};
Expand Down Expand Up @@ -1314,7 +1315,7 @@ impl PackedVq {
}

/// See `Virtq.prep_transfer_from_raw()` documentation.
pub fn prep_transfer_from_raw<T: AsSliceU8 + 'static, K: AsSliceU8 + 'static>(
pub fn prep_transfer_from_raw<T: AsBytes + 'static, K: AsBytes + 'static>(
&self,
master: Rc<Virtq>,
send: Option<(*mut T, BuffSpec<'_>)>,
Expand All @@ -1325,7 +1326,7 @@ impl PackedVq {
(Some((send_data, send_spec)), None) => {
match send_spec {
BuffSpec::Single(size) => {
let data_slice = unsafe { (*send_data).as_slice_u8() };
let data_slice = unsafe { (*send_data).as_bytes() };

// Buffer must have the right size
if data_slice.len() != size.into() {
Expand Down Expand Up @@ -1358,7 +1359,7 @@ impl PackedVq {
})
}
BuffSpec::Multiple(size_lst) => {
let data_slice = unsafe { (*send_data).as_slice_u8() };
let data_slice = unsafe { (*send_data).as_bytes() };
let mut desc_lst: Vec<MemDescr> = Vec::with_capacity(size_lst.len());
let mut index = 0usize;

Expand Down Expand Up @@ -1399,7 +1400,7 @@ impl PackedVq {
})
}
BuffSpec::Indirect(size_lst) => {
let data_slice = unsafe { (*send_data).as_slice_u8() };
let data_slice = unsafe { (*send_data).as_bytes() };
let mut desc_lst: Vec<MemDescr> = Vec::with_capacity(size_lst.len());
let mut index = 0usize;

Expand Down Expand Up @@ -1447,7 +1448,7 @@ impl PackedVq {
(None, Some((recv_data, recv_spec))) => {
match recv_spec {
BuffSpec::Single(size) => {
let data_slice = unsafe { (*recv_data).as_slice_u8() };
let data_slice = unsafe { (*recv_data).as_bytes() };

// Buffer must have the right size
if data_slice.len() != size.into() {
Expand Down Expand Up @@ -1480,7 +1481,7 @@ impl PackedVq {
})
}
BuffSpec::Multiple(size_lst) => {
let data_slice = unsafe { (*recv_data).as_slice_u8() };
let data_slice = unsafe { (*recv_data).as_bytes() };
let mut desc_lst: Vec<MemDescr> = Vec::with_capacity(size_lst.len());
let mut index = 0usize;

Expand Down Expand Up @@ -1521,7 +1522,7 @@ impl PackedVq {
})
}
BuffSpec::Indirect(size_lst) => {
let data_slice = unsafe { (*recv_data).as_slice_u8() };
let data_slice = unsafe { (*recv_data).as_bytes() };
let mut desc_lst: Vec<MemDescr> = Vec::with_capacity(size_lst.len());
let mut index = 0usize;

Expand Down Expand Up @@ -1569,7 +1570,7 @@ impl PackedVq {
(Some((send_data, send_spec)), Some((recv_data, recv_spec))) => {
match (send_spec, recv_spec) {
(BuffSpec::Single(send_size), BuffSpec::Single(recv_size)) => {
let send_data_slice = unsafe { (*send_data).as_slice_u8() };
let send_data_slice = unsafe { (*send_data).as_bytes() };

// Buffer must have the right size
if send_data_slice.len() != send_size.into() {
Expand All @@ -1584,7 +1585,7 @@ impl PackedVq {
Err(vq_err) => return Err(vq_err),
};

let recv_data_slice = unsafe { (*recv_data).as_slice_u8() };
let recv_data_slice = unsafe { (*recv_data).as_bytes() };

// Buffer must have the right size
if recv_data_slice.len() != recv_size.into() {
Expand Down Expand Up @@ -1621,7 +1622,7 @@ impl PackedVq {
})
}
(BuffSpec::Single(send_size), BuffSpec::Multiple(recv_size_lst)) => {
let send_data_slice = unsafe { (*send_data).as_slice_u8() };
let send_data_slice = unsafe { (*send_data).as_bytes() };

// Buffer must have the right size
if send_data_slice.len() != send_size.into() {
Expand All @@ -1636,7 +1637,7 @@ impl PackedVq {
Err(vq_err) => return Err(vq_err),
};

let recv_data_slice = unsafe { (*recv_data).as_slice_u8() };
let recv_data_slice = unsafe { (*recv_data).as_bytes() };
let mut recv_desc_lst: Vec<MemDescr> =
Vec::with_capacity(recv_size_lst.len());
let mut index = 0usize;
Expand Down Expand Up @@ -1684,7 +1685,7 @@ impl PackedVq {
})
}
(BuffSpec::Multiple(send_size_lst), BuffSpec::Multiple(recv_size_lst)) => {
let send_data_slice = unsafe { (*send_data).as_slice_u8() };
let send_data_slice = unsafe { (*send_data).as_bytes() };
let mut send_desc_lst: Vec<MemDescr> =
Vec::with_capacity(send_size_lst.len());
let mut index = 0usize;
Expand All @@ -1710,7 +1711,7 @@ impl PackedVq {
index += usize::from(*byte);
}

let recv_data_slice = unsafe { (*recv_data).as_slice_u8() };
let recv_data_slice = unsafe { (*recv_data).as_bytes() };
let mut recv_desc_lst: Vec<MemDescr> =
Vec::with_capacity(recv_size_lst.len());
let mut index = 0usize;
Expand Down Expand Up @@ -1758,7 +1759,7 @@ impl PackedVq {
})
}
(BuffSpec::Multiple(send_size_lst), BuffSpec::Single(recv_size)) => {
let send_data_slice = unsafe { (*send_data).as_slice_u8() };
let send_data_slice = unsafe { (*send_data).as_bytes() };
let mut send_desc_lst: Vec<MemDescr> =
Vec::with_capacity(send_size_lst.len());
let mut index = 0usize;
Expand All @@ -1784,7 +1785,7 @@ impl PackedVq {
index += usize::from(*byte);
}

let recv_data_slice = unsafe { (*recv_data).as_slice_u8() };
let recv_data_slice = unsafe { (*recv_data).as_bytes() };

// Buffer must have the right size
if recv_data_slice.len() != recv_size.into() {
Expand Down Expand Up @@ -1821,7 +1822,7 @@ impl PackedVq {
})
}
(BuffSpec::Indirect(send_size_lst), BuffSpec::Indirect(recv_size_lst)) => {
let send_data_slice = unsafe { (*send_data).as_slice_u8() };
let send_data_slice = unsafe { (*send_data).as_bytes() };
let mut send_desc_lst: Vec<MemDescr> =
Vec::with_capacity(send_size_lst.len());
let mut index = 0usize;
Expand All @@ -1844,7 +1845,7 @@ impl PackedVq {
index += usize::from(*byte);
}

let recv_data_slice = unsafe { (*recv_data).as_slice_u8() };
let recv_data_slice = unsafe { (*recv_data).as_bytes() };
let mut recv_desc_lst: Vec<MemDescr> =
Vec::with_capacity(recv_size_lst.len());
let mut index = 0usize;
Expand Down
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