add os[1-8]-ref for os refereces, add guide, add README

os7-ref/src/drivers/block/mod.rs

@@ -0,0 +1,24 @@
+mod virtio_blk;
+
+use lazy_static::*;
+use alloc::sync::Arc;
+use easy_fs::BlockDevice;
+type BlockDeviceImpl = virtio_blk::VirtIOBlock;
+
+lazy_static! {
+    pub static ref BLOCK_DEVICE: Arc<dyn BlockDevice> = Arc::new(BlockDeviceImpl::new());
+}
+
+#[allow(unused)]
+pub fn block_device_test() {
+    let block_device = BLOCK_DEVICE.clone();
+    let mut write_buffer = [0u8; 512];
+    let mut read_buffer = [0u8; 512];
+    for i in 0..512 {
+        for byte in write_buffer.iter_mut() { *byte = i as u8; }
+        block_device.write_block(i as usize, &write_buffer);
+        block_device.read_block(i as usize, &mut read_buffer);
+        assert_eq!(write_buffer, read_buffer);
+    }
+    println!("block device test passed!");
+}

os7-ref/src/drivers/block/virtio_blk.rs

@@ -0,0 +1,84 @@
+
+use virtio_drivers::{VirtIOBlk, VirtIOHeader};
+use crate::mm::{
+    PhysAddr,
+    VirtAddr,
+    frame_alloc,
+    frame_dealloc,
+    PhysPageNum,
+    FrameTracker,
+    PageTable,
+    StepByOne,
+    kernel_token,
+};
+use super::BlockDevice;
+use crate::sync::UPSafeCell;
+use alloc::vec::Vec;
+use lazy_static::*;
+
+#[allow(unused)]
+const VIRTIO0: usize = 0x10001000;
+
+pub struct VirtIOBlock(UPSafeCell<VirtIOBlk<'static>>);
+
+lazy_static! {
+    static ref QUEUE_FRAMES: UPSafeCell<Vec<FrameTracker>> = unsafe { 
+        UPSafeCell::new(Vec::new())
+    };
+}
+
+impl BlockDevice for VirtIOBlock {
+    fn read_block(&self, block_id: usize, buf: &mut [u8]) {
+        self.0.exclusive_access()
+        .read_block(block_id, buf)
+        .expect("Error when reading VirtIOBlk");
+    }
+    fn write_block(&self, block_id: usize, buf: &[u8]) {
+        self.0.exclusive_access()
+        .write_block(block_id, buf)
+        .expect("Error when writing VirtIOBlk");
+    }
+}
+
+impl VirtIOBlock {
+    #[allow(unused)]
+    pub fn new() -> Self {
+        unsafe {
+            Self(UPSafeCell::new(VirtIOBlk::new(
+                &mut *(VIRTIO0 as *mut VirtIOHeader)
+            ).unwrap()))
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn virtio_dma_alloc(pages: usize) -> PhysAddr {
+    let mut ppn_base = PhysPageNum(0);
+    for i in 0..pages {
+        let frame = frame_alloc().unwrap();
+        if i == 0 { ppn_base = frame.ppn; }
+        assert_eq!(frame.ppn.0, ppn_base.0 + i);
+        QUEUE_FRAMES.exclusive_access().push(frame);
+    }
+    ppn_base.into()
+}
+
+#[no_mangle]
+pub extern "C" fn virtio_dma_dealloc(pa: PhysAddr, pages: usize) -> i32 {
+    let mut ppn_base: PhysPageNum = pa.into();
+    for _ in 0..pages {
+        frame_dealloc(ppn_base);
+        ppn_base.step();
+    }
+    0
+}
+
+#[no_mangle]
+pub extern "C" fn virtio_phys_to_virt(paddr: PhysAddr) -> VirtAddr {
+    VirtAddr(paddr.0)
+}
+
+#[no_mangle]
+pub extern "C" fn virtio_virt_to_phys(vaddr: VirtAddr) -> PhysAddr {
+    PageTable::from_token(kernel_token()).translate_va(vaddr).unwrap()
+}

os7-ref/src/drivers/mod.rs

@@ -0,0 +1,3 @@
+mod block;
+
+pub use block::BLOCK_DEVICE;