Implement pci bus probing and fix a bug in virtio_mmio

kernel/Makefile

@@ -61,6 +61,8 @@ endif
 ### qemu options ###
 qemu_opts := \
 	-smp cores=$(smp)
+qemu_net_opts := \
+	-netdev type=tap,id=net0,script=no,downscript=no
 
 ifeq ($(arch), x86_64)
 qemu_opts += \
@@ -68,6 +70,8 @@ qemu_opts += \
 	-drive format=raw,file=$(SFSIMG),media=disk,cache=writeback \
 	-serial mon:stdio \
 	-device isa-debug-exit
+qemu_net_opts += \
+	-device virtio-net-pci,netdev=net0
 
 else ifeq ($(arch), riscv32)
 qemu_opts += \
@@ -75,6 +79,9 @@ qemu_opts += \
 	-kernel $(bin) \
 	-drive file=$(SFSIMG),format=raw,id=sfs \
 	-device virtio-blk-device,drive=sfs
+qemu_net_opts += \
+	-device virtio-net-device,netdev=net0
+
 ifdef m_mode
 qemu_opts += -cpu rv32imacu-nommu
 endif
@@ -85,6 +92,9 @@ qemu_opts += \
 	-kernel $(bin) \
 	-drive file=$(SFSIMG),format=raw,id=sfs \
 	-device virtio-blk-device,drive=sfs
+qemu_net_opts += \
+	-device virtio-net-device,netdev=net0
+
 ifdef m_mode
 qemu_opts += -cpu rv64imacu-nommu
 endif
@@ -182,9 +192,7 @@ justrun:
 	@qemu-system-$(arch) $(qemu_opts)
 
 justrunnet: build
-	@sudo qemu-system-$(arch) $(qemu_opts) \
+	@sudo qemu-system-$(arch) $(qemu_opts) $(qemu_net_opts)
-		-netdev type=tap,id=net0,script=no,downscript=no \
-		-device virtio-net-device,netdev=net0 \
 
 justrunui: build
 	@qemu-system-$(arch) $(qemu_opts) \

kernel/src/arch/x86_64/mod.rs

@@ -43,6 +43,8 @@ pub extern "C" fn _start(boot_info: &'static BootInfo) -> ! {
 
     driver::init();
 
+    crate::drivers::init();
+
     crate::process::init();
 
     AP_CAN_INIT.store(true, Ordering::Relaxed);

kernel/src/drivers/bus/mod.rs

@@ -1 +1,3 @@
 pub mod virtio_mmio;
+#[cfg(target_arch = "x86_64")]
+pub mod pci;

kernel/src/drivers/bus/pci.rs

@@ -0,0 +1,98 @@
+use x86_64::instructions::port::Port;
+use crate::logging::*;
+
+const VENDOR: u32 = 0x00;
+const DEVICE: u32 = 0x02;
+const STATUS: u32 = 0x06;
+const SUBCLASS: u32 = 0x0a;
+const CLASS: u32 = 0x0b;
+const HEADER: u32 = 0x0e;
+
+const PCI_ADDR_PORT: u16 = 0xcf8;
+const PCI_DATA_PORT: u16 = 0xcfc;
+
+struct PciTag(u32);
+
+impl PciTag {
+    pub fn new(bus: u32, dev: u32, func: u32) -> PciTag {
+        PciTag(bus << 16 | dev << 11 | func << 8)
+    }
+
+    pub fn bus(&self) -> u32 {
+        (self.0 >> 16) & 0xFF
+    }
+
+    pub fn dev(&self) -> u32 {
+        (self.0 >> 11) & 0x1F
+    }
+
+    pub fn func(&self) -> u32 {
+        (self.0 >> 8) & 0x7
+    }
+
+    // biscuit/src/pci/pci.go
+    pub unsafe fn read(&self, reg: u32, width: u32) -> u32 {
+        // spans in one reg
+        assert_eq!(reg / 4, (reg + width - 1) / 4);
+
+        let enable = 1 << 31;
+        let rsh = reg % 4;
+        let r = reg - rsh;
+        let t = enable | self.0 | r;
+
+        let mut pci_addr: Port<u32> = Port::new(PCI_ADDR_PORT);
+        let mut pci_data: Port<u32> = Port::new(PCI_DATA_PORT);
+
+        pci_addr.write(t);
+        let d = pci_data.read();
+        pci_addr.write(0);
+
+        let ret = d >> (rsh * 8);
+        let m = (1 << (8 * width)) - 1;
+        return ret & m;
+    }
+
+    pub unsafe fn write(&self, reg: u32, val: u32) {
+        assert_eq!(reg & 3, 0);
+
+        let enable = 1 << 31;
+        let t = enable | self.0 | reg;
+
+        let mut pci_addr: Port<u32> = Port::new(PCI_ADDR_PORT);
+        let mut pci_data: Port<u32> = Port::new(PCI_DATA_PORT);
+
+        pci_addr.write(t);
+        pci_data.write(val);
+        pci_addr.write(0);
+    }
+
+    pub fn describe(&self) -> bool {
+        unsafe {
+            let v = self.read(VENDOR, 2);
+            if v == 0xffff {
+                return false;
+            }
+            let d = self.read(DEVICE, 2);
+            let mf = self.read(HEADER, 1);
+            let cl = self.read(CLASS, 1);
+            let scl = self.read(SUBCLASS, 1);
+            info!("{}: {}: {}: {:#X} {:#X} ({} {})", self.bus(), self.dev(), self.func(), v, d, cl, scl);
+            return mf & 0x80 != 0;
+        }
+    }
+}
+
+pub fn init() {
+    for bus in 0..256 {
+        for dev in 0..32 {
+            let tag = PciTag::new(bus, dev, 0);
+            if tag.describe() {
+                for func in 1..8 {
+                    let tag = PciTag::new(bus, dev, func);
+                    tag.describe();
+                }
+            }
+        }
+    }
+    info!("Init pci");
+}

kernel/src/drivers/bus/virtio_mmio.rs

@@ -208,7 +208,8 @@ impl VirtIOVirtqueue {
         let mut output = Vec::new();
         loop {
             let flags = VirtIOVirtqueueFlag::from_bits_truncate(desc[cur].flags.read());
-            let buffer = unsafe { slice::from_raw_parts(desc[cur].addr.read() as *const u8, desc[cur].len.read() as usize) };
+            let addr = desc[cur].addr.read() as u64 - MEMORY_OFFSET as u64 + KERNEL_OFFSET as u64;
+            let buffer = unsafe { slice::from_raw_parts(addr as *const u8, desc[cur].len.read() as usize) };
             if flags.contains(VirtIOVirtqueueFlag::WRITE) {
                 input.push(buffer);
             } else {

kernel/src/drivers/mod.rs

@@ -54,6 +54,12 @@ lazy_static! {
     pub static ref NET_DRIVERS: SpinNoIrqLock<Vec<Box<NetDriver>>> = SpinNoIrqLock::new(Vec::new());
 }
 
+#[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))]
 pub fn init(dtb: usize) {
     device_tree::init(dtb);
 }
+
+#[cfg(target_arch = "x86_64")]
+pub fn init() {
+    bus::pci::init();
+}

kernel/src/drivers/net/virtio_net.rs

@@ -168,9 +168,8 @@ impl phy::TxToken for VirtIONetTxToken {
                 unsafe { slice::from_raw_parts_mut(page as *mut u8, PAGE_SIZE) }
             }
         };
-        let output_buffer = &mut output[size_of::<VirtIONetHeader>()..(size_of::<VirtIONetHeader>() +len)];
+        let output_buffer = &mut output[size_of::<VirtIONetHeader>()..(size_of::<VirtIONetHeader>() + len)];
         let result = f(output_buffer);
-        println!("output {:?}", output_buffer);
 
         let mut driver = (self.0).0.lock();
         assert!(driver.queues[VIRTIO_QUEUE_TRANSMIT].add_and_notify(&[], &[output], 0));