refactor(virtio/mmio): migrate MmioRegisterLayout to virtio-spec

Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>

src/arch/riscv64/kernel/devicetree.rs

@@ -1,4 +1,11 @@
+#[cfg(all(feature = "tcp", not(feature = "pci")))]
+use core::ptr::NonNull;
+
 use fdt::Fdt;
+#[cfg(all(feature = "tcp", not(feature = "pci")))]
+use virtio_spec::mmio::{DeviceRegisterVolatileFieldAccess, DeviceRegisters};
+#[cfg(all(feature = "tcp", not(feature = "pci")))]
+use volatile::VolatileRef;
 
 #[cfg(feature = "gem-net")]
 use crate::arch::mm::VirtAddr;
@@ -9,11 +16,11 @@ use crate::arch::riscv64::kernel::mmio::MmioDriver;
 use crate::arch::riscv64::mm::{paging, PhysAddr};
 #[cfg(feature = "gem-net")]
 use crate::drivers::net::gem;
+#[cfg(all(feature = "tcp", not(feature = "pci")))]
+use crate::drivers::virtio::transport::mmio::DevId;
 #[cfg(all(feature = "tcp", not(feature = "pci"), not(feature = "gem-net")))]
 use crate::drivers::virtio::transport::mmio::{self as mmio_virtio, VirtioDriver};
 #[cfg(all(feature = "tcp", not(feature = "pci")))]
-use crate::drivers::virtio::transport::mmio::{DevId, MmioRegisterLayout};
-#[cfg(all(feature = "tcp", not(feature = "pci")))]
 use crate::kernel::mmio::register_driver;
 
 static mut PLATFORM_MODEL: Model = Model::Unknown;
@@ -184,10 +191,11 @@ pub fn init_drivers() {
 				);
 
 				// Verify the first register value to find out if this is really an MMIO magic-value.
-				let mmio = &mut *(virtio_region.starting_address as *mut MmioRegisterLayout);
+				let ptr = virtio_region.starting_address as *mut DeviceRegisters;
+				let mmio = VolatileRef::new(NonNull::new(ptr).unwrap());
 
-				let magic = mmio.get_magic_value();
-				let version = mmio.get_version();
+				let magic = mmio.as_ptr().magic_value().read().to_ne();
+				let version = mmio.as_ptr().version().read().to_ne();
 
 				const MMIO_MAGIC_VALUE: u32 = 0x74726976;
 				if magic != MMIO_MAGIC_VALUE {
@@ -201,7 +209,7 @@ pub fn init_drivers() {
 					trace!("Found a MMIO-device at {mmio:p}");
 
 					// Verify the device-ID to find the network card
-					let id = mmio.get_device_id();
+					let id = DevId::from(mmio.as_ptr().device_id().read().to_ne());
 
 					if id != DevId::VIRTIO_DEV_ID_NET {
 						debug!("It's not a network card at {mmio:p}");

src/arch/x86_64/kernel/mmio.rs

@@ -1,17 +1,20 @@
 use alloc::string::String;
 use alloc::vec::Vec;
+use core::ptr::NonNull;
 use core::{ptr, str};
 
 use align_address::Align;
 use hermit_sync::{without_interrupts, InterruptTicketMutex};
+use virtio_spec::mmio::{DeviceRegisterVolatileFieldAccess, DeviceRegisters};
+use volatile::VolatileRef;
 
 use crate::arch::x86_64::mm::paging::{
 	BasePageSize, PageSize, PageTableEntryFlags, PageTableEntryFlagsExt,
 };
 use crate::arch::x86_64::mm::{paging, PhysAddr};
 use crate::drivers::net::virtio_net::VirtioNetDriver;
 use crate::drivers::virtio::transport::mmio as mmio_virtio;
-use crate::drivers::virtio::transport::mmio::{DevId, MmioRegisterLayout, VirtioDriver};
+use crate::drivers::virtio::transport::mmio::{DevId, VirtioDriver};
 use crate::env;
 
 pub const MAGIC_VALUE: u32 = 0x74726976;
@@ -36,12 +39,12 @@ impl MmioDriver {
 	}
 }
 
-unsafe fn check_ptr(ptr: *mut u8) -> Option<&'static mut MmioRegisterLayout> {
+unsafe fn check_ptr(ptr: *mut u8) -> Option<VolatileRef<'static, DeviceRegisters>> {
 	// Verify the first register value to find out if this is really an MMIO magic-value.
-	let mmio = unsafe { ptr.cast::<MmioRegisterLayout>().as_mut().unwrap() };
+	let mmio = unsafe { VolatileRef::new(NonNull::new(ptr.cast::<DeviceRegisters>()).unwrap()) };
 
-	let magic = mmio.get_magic_value();
-	let version = mmio.get_version();
+	let magic = mmio.as_ptr().magic_value().read().to_ne();
+	let version = mmio.as_ptr().version().read().to_ne();
 
 	if magic != MAGIC_VALUE {
 		trace!("It's not a MMIO-device at {mmio:p}");
@@ -57,7 +60,7 @@ unsafe fn check_ptr(ptr: *mut u8) -> Option<&'static mut MmioRegisterLayout> {
 	trace!("Found a MMIO-device at {mmio:p}");
 
 	// Verify the device-ID to find the network card
-	let id = mmio.get_device_id();
+	let id = DevId::from(mmio.as_ptr().device_id().read().to_ne());
 
 	if id != DevId::VIRTIO_DEV_ID_NET {
 		trace!("It's not a network card at {mmio:p}");
@@ -69,7 +72,7 @@ unsafe fn check_ptr(ptr: *mut u8) -> Option<&'static mut MmioRegisterLayout> {
 
 fn check_linux_args(
 	linux_mmio: &'static [String],
-) -> Result<(&'static mut MmioRegisterLayout, u8), &'static str> {
+) -> Result<(VolatileRef<'static, DeviceRegisters>, u8), &'static str> {
 	let virtual_address =
 		crate::arch::mm::virtualmem::allocate(BasePageSize::SIZE as usize).unwrap();
 
@@ -123,7 +126,7 @@ fn check_linux_args(
 	Err("Network card not found!")
 }
 
-fn guess_device() -> Result<(&'static mut MmioRegisterLayout, u8), &'static str> {
+fn guess_device() -> Result<(VolatileRef<'static, DeviceRegisters>, u8), &'static str> {
 	// Trigger page mapping in the first iteration!
 	let mut current_page = 0;
 	let virtual_address =
@@ -175,7 +178,7 @@ fn guess_device() -> Result<(&'static mut MmioRegisterLayout, u8), &'static str>
 
 /// Tries to find the network device within the specified address range.
 /// Returns a reference to it within the Ok() if successful or an Err() on failure.
-fn detect_network() -> Result<(&'static mut MmioRegisterLayout, u8), &'static str> {
+fn detect_network() -> Result<(VolatileRef<'static, DeviceRegisters>, u8), &'static str> {
 	let linux_mmio = env::mmio();
 
 	if !linux_mmio.is_empty() {

src/drivers/net/virtio_mmio.rs

@@ -4,17 +4,18 @@
 
 use alloc::rc::Rc;
 use alloc::vec::Vec;
-use core::ptr;
 use core::ptr::read_volatile;
 use core::str::FromStr;
 use core::sync::atomic::{fence, Ordering};
 
 use smoltcp::phy::ChecksumCapabilities;
+use virtio_spec::mmio::{DeviceRegisterVolatileFieldAccess, DeviceRegisters};
+use volatile::VolatileRef;
 
 use crate::drivers::net::virtio_net::constants::Status;
 use crate::drivers::net::virtio_net::{CtrlQueue, NetDevCfg, RxQueues, TxQueues, VirtioNetDriver};
 use crate::drivers::virtio::error::{VirtioError, VirtioNetError};
-use crate::drivers::virtio::transport::mmio::{ComCfg, IsrStatus, MmioRegisterLayout, NotifCfg};
+use crate::drivers::virtio::transport::mmio::{ComCfg, IsrStatus, NotifCfg};
 use crate::drivers::virtio::virtqueue::Virtq;
 
 /// Virtio's network device configuration structure.
@@ -110,18 +111,25 @@ impl NetDevCfgRaw {
 impl VirtioNetDriver {
 	pub fn new(
 		dev_id: u16,
-		registers: &'static mut MmioRegisterLayout,
+		mut registers: VolatileRef<'static, DeviceRegisters>,
 		irq: u8,
 	) -> Result<Self, VirtioNetError> {
-		let dev_cfg_raw: &'static NetDevCfgRaw =
-			unsafe { &*(ptr::with_exposed_provenance(ptr::from_ref(registers).addr() + 0xFC)) };
+		let dev_cfg_raw: &'static NetDevCfgRaw = unsafe {
+			&*registers
+				.borrow_mut()
+				.as_mut_ptr()
+				.config_generation()
+				.as_raw_ptr()
+				.cast::<NetDevCfgRaw>()
+				.as_ptr()
+		};
 		let dev_cfg = NetDevCfg {
 			raw: dev_cfg_raw,
 			dev_id,
 			features: virtio_spec::net::F::empty(),
 		};
-		let isr_stat = IsrStatus::new(registers);
-		let notif_cfg = NotifCfg::new(registers);
+		let isr_stat = IsrStatus::new(registers.borrow_mut());
+		let notif_cfg = NotifCfg::new(registers.borrow_mut());
 
 		let mtu = if let Some(my_mtu) = hermit_var!("HERMIT_MTU") {
 			u16::from_str(&my_mtu).unwrap()
@@ -159,7 +167,7 @@ impl VirtioNetDriver {
 	/// [VirtioNetDriver](structs.virtionetdriver.html) or an [VirtioError](enums.virtioerror.html).
 	pub fn init(
 		dev_id: u16,
-		registers: &'static mut MmioRegisterLayout,
+		registers: VolatileRef<'static, DeviceRegisters>,
 		irq_no: u8,
 	) -> Result<VirtioNetDriver, VirtioError> {
 		if let Ok(mut drv) = VirtioNetDriver::new(dev_id, registers, irq_no) {