feat(firecracker): create an FDT

.github/workflows/ci.yml

@@ -124,6 +124,8 @@ jobs:
           ARCH="$(uname -m)"
           release_url="https://github.com/firecracker-microvm/firecracker/releases"
           latest=$(basename $(curl -fsSLI -o /dev/null -w  %{url_effective} ${release_url}/latest))
+          # FIXME: remove once 1.7.0 and above work
+          latest=v1.6.0
           curl -L ${release_url}/download/${latest}/firecracker-${latest}-${ARCH}.tgz \
           | tar -xz
 

src/arch/x86_64/firecracker.rs

@@ -2,7 +2,9 @@ use core::ptr::write_bytes;
 use core::{ptr, slice};
 
 use align_address::Align;
-use hermit_entry::boot_info::{BootInfo, HardwareInfo, PlatformInfo, SerialPortBase};
+use hermit_entry::boot_info::{
+	BootInfo, DeviceTreeAddress, HardwareInfo, PlatformInfo, SerialPortBase,
+};
 use hermit_entry::elf::LoadedKernel;
 use hermit_entry::fc::{
 	BOOT_FLAG_OFFSET, CMD_LINE_PTR_OFFSET, CMD_LINE_SIZE_OFFSET, E820_ENTRIES_OFFSET,
@@ -15,6 +17,7 @@ use x86_64::structures::paging::{PageSize, PageTableFlags, Size2MiB, Size4KiB};
 
 use super::physicalmem::PhysAlloc;
 use super::{paging, KERNEL_STACK_SIZE, SERIAL_IO_PORT};
+use crate::fdt::Fdt;
 use crate::BootInfoExt;
 
 extern "C" {
@@ -175,6 +178,8 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		);
 	}
 
+	let mut fdt = Fdt::new("firecracker").unwrap();
+
 	// Load the boot_param memory-map information
 	let linux_e820_entries =
 		unsafe { *(sptr::from_exposed_addr::<u8>(boot_params + E820_ENTRIES_OFFSET)) };
@@ -203,6 +208,8 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 
 		let entry_end = entry_start + entry_size;
 
+		fdt = fdt.memory(entry_start..entry_end).unwrap();
+
 		if start_address == 0 {
 			start_address = entry_start as usize;
 		}
@@ -220,11 +227,20 @@ pub unsafe fn boot_kernel(kernel_info: LoadedKernel) -> ! {
 		start_address, end_address
 	);
 
+	if let Some(command_line) = command_line {
+		fdt = fdt.bootargs(command_line).unwrap();
+	}
+
+	let fdt = fdt.finish().unwrap();
+
+	let device_tree =
+		DeviceTreeAddress::new(u64::try_from(fdt.leak().as_ptr().expose_addr()).unwrap());
+
 	let boot_info = BootInfo {
 		hardware_info: HardwareInfo {
 			phys_addr_range: start_address as u64..end_address as u64,
 			serial_port_base: SerialPortBase::new(SERIAL_IO_PORT),
-			device_tree: None,
+			device_tree,
 		},
 		load_info,
 		platform_info: PlatformInfo::LinuxBootParams {

src/main.rs

@@ -13,15 +13,12 @@ mod macros;
 
 mod arch;
 mod bump_allocator;
-#[cfg(any(target_os = "uefi", all(target_arch = "x86_64", not(feature = "fc"))))]
+#[cfg(any(target_os = "uefi", target_arch = "x86_64"))]
 mod fdt;
 mod log;
 mod os;
 
-#[cfg(any(
-	target_os = "uefi",
-	all(target_arch = "x86_64", target_os = "none", not(feature = "fc"))
-))]
+#[cfg(any(target_os = "uefi", all(target_arch = "x86_64", target_os = "none")))]
 extern crate alloc;
 
 trait BootInfoExt {