Support streaming dma mappings

framework/jinux-frame/src/vm/dma/dma_coherent.rs

@@ -158,3 +158,82 @@ impl HasPaddr for DmaCoherent {
         self.inner.vm_segment.start_paddr()
     }
 }
+
+#[if_cfg_ktest]
+mod test {
+    use super::*;
+    use crate::vm::VmAllocOptions;
+    use alloc::vec;
+
+    #[ktest]
+    fn map_with_coherent_device() {
+        let vm_segment = VmAllocOptions::new(1)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let dma_coherent = DmaCoherent::map(vm_segment.clone(), true).unwrap();
+        assert!(dma_coherent.paddr() == vm_segment.paddr());
+    }
+
+    #[ktest]
+    fn map_with_incoherent_device() {
+        let vm_segment = VmAllocOptions::new(1)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let dma_coherent = DmaCoherent::map(vm_segment.clone(), false).unwrap();
+        assert!(dma_coherent.paddr() == vm_segment.paddr());
+        let mut page_table = KERNEL_PAGE_TABLE.get().unwrap().lock();
+        assert!(page_table
+            .flags(paddr_to_vaddr(vm_segment.paddr()))
+            .unwrap()
+            .contains(PageTableFlags::NO_CACHE))
+    }
+
+    #[ktest]
+    fn duplicate_map() {
+        let vm_segment_parent = VmAllocOptions::new(2)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let vm_segment_child = vm_segment_parent.range(0..1);
+        let dma_coherent_parent = DmaCoherent::map(vm_segment_parent, false);
+        let dma_coherent_child = DmaCoherent::map(vm_segment_child, false);
+        assert!(dma_coherent_child.is_err());
+    }
+
+    #[ktest]
+    fn read_and_write() {
+        let vm_segment = VmAllocOptions::new(2)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let dma_coherent = DmaCoherent::map(vm_segment, false).unwrap();
+
+        let buf_write = vec![1u8; 2 * PAGE_SIZE];
+        dma_coherent.write_bytes(0, &buf_write).unwrap();
+        let mut buf_read = vec![0u8; 2 * PAGE_SIZE];
+        dma_coherent.read_bytes(0, &mut buf_read).unwrap();
+        assert_eq!(buf_write, buf_read);
+    }
+
+    #[ktest]
+    fn reader_and_wirter() {
+        let vm_segment = VmAllocOptions::new(2)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let dma_coherent = DmaCoherent::map(vm_segment, false).unwrap();
+
+        let buf_write = vec![1u8; PAGE_SIZE];
+        let mut writer = dma_coherent.writer();
+        writer.write(&mut buf_write.as_slice().into());
+        writer.write(&mut buf_write.as_slice().into());
+
+        let mut buf_read = vec![0u8; 2 * PAGE_SIZE];
+        let buf_write = vec![1u8; 2 * PAGE_SIZE];
+        let mut reader = dma_coherent.reader();
+        reader.read(&mut buf_read.as_mut_slice().into());
+        assert_eq!(buf_read, buf_write);
+    }
+}

framework/jinux-frame/src/vm/dma/dma_stream.rs

@@ -0,0 +1,262 @@
+use alloc::sync::Arc;
+use core::arch::x86_64::_mm_clflush;
+use core::ops::Range;
+
+use crate::arch::iommu;
+use crate::error::Error;
+use crate::vm::{
+    dma::{dma_type, Daddr, DmaType},
+    HasPaddr, Paddr, VmSegment, PAGE_SIZE,
+};
+use crate::vm::{VmIo, VmReader, VmWriter};
+
+use super::{check_and_insert_dma_mapping, remove_dma_mapping, DmaError, HasDaddr};
+
+/// A streaming DMA mapping. Users must synchronize data
+/// before reading or after writing to ensure consistency.
+///
+/// The mapping is automatically destroyed when this object
+/// is dropped.
+#[derive(Debug, Clone)]
+pub struct DmaStream {
+    inner: Arc<DmaStreamInner>,
+}
+
+#[derive(Debug)]
+struct DmaStreamInner {
+    vm_segment: VmSegment,
+    start_daddr: Daddr,
+    is_cache_coherent: bool,
+    direction: DmaDirection,
+}
+
+/// `DmaDirection` limits the data flow direction of `DmaStream` and
+/// prevents users from reading and writing to `DmaStream` unexpectedly.
+#[derive(Debug, PartialEq, Clone)]
+pub enum DmaDirection {
+    ToDevice,
+    FromDevice,
+    Bidirectional,
+}
+
+impl DmaStream {
+    /// Establish DMA stream mapping for a given `VmSegment`.
+    ///
+    /// The method fails if the segment already belongs to a DMA mapping.
+    pub fn map(
+        vm_segment: VmSegment,
+        direction: DmaDirection,
+        is_cache_coherent: bool,
+    ) -> Result<Self, DmaError> {
+        let frame_count = vm_segment.nframes();
+        let start_paddr = vm_segment.start_paddr();
+        if !check_and_insert_dma_mapping(start_paddr, frame_count) {
+            return Err(DmaError::AlreadyMapped);
+        }
+        let start_daddr = match dma_type() {
+            DmaType::Direct => start_paddr as Daddr,
+            DmaType::Iommu => {
+                for i in 0..frame_count {
+                    let paddr = start_paddr + (i * PAGE_SIZE);
+                    // Safety: the `paddr` is restricted by the `start_paddr` and `frame_count` of the `vm_segment`.
+                    unsafe {
+                        iommu::map(paddr as Daddr, paddr).unwrap();
+                    }
+                }
+                start_paddr as Daddr
+            }
+            DmaType::Tdx => {
+                todo!()
+            }
+        };
+
+        Ok(Self {
+            inner: Arc::new(DmaStreamInner {
+                vm_segment,
+                start_daddr,
+                is_cache_coherent,
+                direction,
+            }),
+        })
+    }
+
+    /// Get the underlying VM segment.
+    ///
+    /// Usually, the CPU side should not access the memory
+    /// after the DMA mapping is established because
+    /// there is a chance that the device is updating
+    /// the memory. Do this at your own risk.
+    pub fn vm_segment(&self) -> &VmSegment {
+        &self.inner.vm_segment
+    }
+
+    pub fn nbytes(&self) -> usize {
+        self.inner.vm_segment.nbytes()
+    }
+
+    /// Synchronize the streaming DMA mapping with the device.
+    ///
+    /// This method should be called under one of the two conditions:
+    /// 1. The data of the stream DMA mapping has been updated by the device side.
+    /// The CPU side needs to call the `sync` method before reading data (e.g., using `read_bytes`).
+    /// 2. The data of the stream DMA mapping has been updated by the CPU side
+    /// (e.g., using `write_bytes`).
+    /// Before the CPU side notifies the device side to read, it must call the `sync` method first.
+    pub fn sync(&self, byte_range: Range<usize>) -> Result<(), Error> {
+        if byte_range.end > self.nbytes() {
+            return Err(Error::InvalidArgs);
+        }
+        if self.inner.is_cache_coherent {
+            return Ok(());
+        }
+        if dma_type() == DmaType::Tdx {
+            // copy pages.
+            todo!("support dma for tdx")
+        } else {
+            let start_va = self.inner.vm_segment.as_ptr();
+            // TODO: Query the CPU for the cache line size via CPUID, we use 64 bytes as the cache line size here.
+            for i in byte_range.step_by(64) {
+                // Safety: the addresses is limited by a valid `byte_range`.
+                unsafe {
+                    _mm_clflush(start_va.wrapping_add(i));
+                }
+            }
+            Ok(())
+        }
+    }
+}
+
+impl HasDaddr for DmaStream {
+    fn daddr(&self) -> Daddr {
+        self.inner.start_daddr
+    }
+}
+
+impl Drop for DmaStreamInner {
+    fn drop(&mut self) {
+        let frame_count = self.vm_segment.nframes();
+        let start_paddr = self.vm_segment.start_paddr();
+        match dma_type() {
+            DmaType::Direct => {}
+            DmaType::Iommu => {
+                for i in 0..frame_count {
+                    let paddr = start_paddr + (i * PAGE_SIZE);
+                    iommu::unmap(paddr).unwrap();
+                }
+            }
+            DmaType::Tdx => {
+                todo!();
+            }
+        }
+        remove_dma_mapping(start_paddr, frame_count);
+    }
+}
+
+impl VmIo for DmaStream {
+    /// Read data into the buffer.
+    fn read_bytes(&self, offset: usize, buf: &mut [u8]) -> Result<(), Error> {
+        if self.inner.direction == DmaDirection::ToDevice {
+            return Err(Error::AccessDenied);
+        }
+        self.inner.vm_segment.read_bytes(offset, buf)
+    }
+
+    /// Write data from the buffer.
+    fn write_bytes(&self, offset: usize, buf: &[u8]) -> Result<(), Error> {
+        if self.inner.direction == DmaDirection::FromDevice {
+            return Err(Error::AccessDenied);
+        }
+        self.inner.vm_segment.write_bytes(offset, buf)
+    }
+}
+
+impl<'a> DmaStream {
+    /// Returns a reader to read data from it.
+    pub fn reader(&'a self) -> Result<VmReader<'a>, Error> {
+        if self.inner.direction == DmaDirection::ToDevice {
+            return Err(Error::AccessDenied);
+        }
+        Ok(self.inner.vm_segment.reader())
+    }
+
+    /// Returns a writer to write data into it.
+    pub fn writer(&'a self) -> Result<VmWriter<'a>, Error> {
+        if self.inner.direction == DmaDirection::FromDevice {
+            return Err(Error::AccessDenied);
+        }
+        Ok(self.inner.vm_segment.writer())
+    }
+}
+
+impl HasPaddr for DmaStream {
+    fn paddr(&self) -> Paddr {
+        self.inner.vm_segment.start_paddr()
+    }
+}
+
+#[if_cfg_ktest]
+mod test {
+    use super::*;
+    use crate::vm::VmAllocOptions;
+    use alloc::vec;
+
+    #[ktest]
+    fn streaming_map() {
+        let vm_segment = VmAllocOptions::new(1)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let dma_stream =
+            DmaStream::map(vm_segment.clone(), DmaDirection::Bidirectional, true).unwrap();
+        assert!(dma_stream.paddr() == vm_segment.paddr());
+    }
+
+    #[ktest]
+    fn duplicate_map() {
+        let vm_segment_parent = VmAllocOptions::new(2)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let vm_segment_child = vm_segment_parent.range(0..1);
+        let dma_stream_parent =
+            DmaStream::map(vm_segment_parent, DmaDirection::Bidirectional, false);
+        let dma_stream_child = DmaStream::map(vm_segment_child, DmaDirection::Bidirectional, false);
+        assert!(dma_stream_child.is_err());
+    }
+
+    #[ktest]
+    fn read_and_write() {
+        let vm_segment = VmAllocOptions::new(2)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let dma_stream = DmaStream::map(vm_segment, DmaDirection::Bidirectional, false).unwrap();
+
+        let buf_write = vec![1u8; 2 * PAGE_SIZE];
+        dma_stream.write_bytes(0, &buf_write).unwrap();
+        dma_stream.sync(0..2 * PAGE_SIZE).unwrap();
+        let mut buf_read = vec![0u8; 2 * PAGE_SIZE];
+        dma_stream.read_bytes(0, &mut buf_read).unwrap();
+        assert_eq!(buf_write, buf_read);
+    }
+
+    #[ktest]
+    fn reader_and_wirter() {
+        let vm_segment = VmAllocOptions::new(2)
+            .is_contiguous(true)
+            .alloc_contiguous()
+            .unwrap();
+        let dma_stream = DmaStream::map(vm_segment, DmaDirection::Bidirectional, false).unwrap();
+
+        let buf_write = vec![1u8; PAGE_SIZE];
+        let mut writer = dma_stream.writer().unwrap();
+        writer.write(&mut buf_write.as_slice().into());
+        writer.write(&mut buf_write.as_slice().into());
+        dma_stream.sync(0..2 * PAGE_SIZE).unwrap();
+        let mut buf_read = vec![0u8; 2 * PAGE_SIZE];
+        let buf_write = vec![1u8; 2 * PAGE_SIZE];
+        let mut reader = dma_stream.reader().unwrap();
+        reader.read(&mut buf_read.as_mut_slice().into());
+        assert_eq!(buf_read, buf_write);
+    }
+}

framework/jinux-frame/src/vm/dma/mod.rs

@@ -1,4 +1,5 @@
 mod dma_coherent;
+mod dma_stream;
 
 use alloc::collections::BTreeSet;
 use spin::Once;
@@ -8,6 +9,7 @@ use crate::{arch::iommu::has_iommu, config::PAGE_SIZE, sync::SpinLock};
 use super::Paddr;
 
 pub use dma_coherent::DmaCoherent;
+pub use dma_stream::{DmaDirection, DmaStream};
 
 /// If a device performs DMA to read or write system
 /// memory, the addresses used by the device are device addresses.

framework/jinux-frame/src/vm/mod.rs

@@ -19,7 +19,7 @@ mod space;
 
 use crate::config::{KERNEL_OFFSET, PAGE_SIZE, PHYS_OFFSET};
 
-pub use self::dma::{DmaCoherent, HasDaddr};
+pub use self::dma::{DmaCoherent, DmaDirection, DmaStream, HasDaddr};
 pub use self::frame::{VmFrame, VmFrameVec, VmFrameVecIter, VmReader, VmSegment, VmWriter};
 pub use self::io::VmIo;
 pub use self::options::VmAllocOptions;