arch, vmm: Enable initramfs on AArch64

Ported Firecracker commit 144b6c.

Signed-off-by: Michael Zhao <michael.zhao@arm.com>

arch/src/aarch64/mod.rs

@@ -35,8 +35,8 @@ pub enum Error {
     /// Failed to create a GIC.
     SetupGIC(gic::Error),
 
-    /// Failed to compute the initrd address.
-    InitrdAddress,
+    /// Failed to compute the initramfs address.
+    InitramfsAddress,
 
     /// Error configuring the general purpose registers
     REGSConfiguration(regs::Error),
@@ -165,6 +165,26 @@ pub fn configure_system<T: DeviceInfoForFDT + Clone + Debug>(
     Ok(())
 }
 
+/// Returns the memory address where the initramfs could be loaded.
+pub fn initramfs_load_addr(
+    guest_mem: &GuestMemoryMmap,
+    initramfs_size: usize,
+) -> super::Result<u64> {
+    let round_to_pagesize = |size| (size + (super::PAGE_SIZE - 1)) & !(super::PAGE_SIZE - 1);
+    match GuestAddress(get_fdt_addr(&guest_mem))
+        .checked_sub(round_to_pagesize(initramfs_size) as u64)
+    {
+        Some(offset) => {
+            if guest_mem.address_in_range(offset) {
+                Ok(offset.raw_value())
+            } else {
+                Err(super::Error::AArch64Setup(Error::InitramfsAddress))
+            }
+        }
+        None => Err(super::Error::AArch64Setup(Error::InitramfsAddress)),
+    }
+}
+
 /// Returns the memory address where the kernel could be loaded.
 pub fn get_kernel_start() -> u64 {
     layout::RAM_64BIT_START

arch/src/lib.rs

@@ -88,8 +88,8 @@ pub mod aarch64;
 #[cfg(target_arch = "aarch64")]
 pub use aarch64::{
     arch_memory_regions, configure_system, configure_vcpu, fdt::DeviceInfoForFDT,
-    get_host_cpu_phys_bits, get_kernel_start, layout, layout::CMDLINE_MAX_SIZE, layout::IRQ_BASE,
-    layout::IRQ_MAX, EntryPoint,
+    get_host_cpu_phys_bits, get_kernel_start, initramfs_load_addr, layout,
+    layout::CMDLINE_MAX_SIZE, layout::IRQ_BASE, layout::IRQ_MAX, EntryPoint,
 };
 
 #[cfg(target_arch = "x86_64")]

vmm/src/vm.rs

@@ -47,12 +47,10 @@ use linux_loader::loader::elf::PvhBootCapability::PvhEntryPresent;
 use linux_loader::loader::KernelLoader;
 use signal_hook::{iterator::Signals, SIGINT, SIGTERM, SIGWINCH};
 use std::collections::HashMap;
-#[cfg(target_arch = "x86_64")]
 use std::convert::TryInto;
 use std::ffi::CString;
 use std::fs::{File, OpenOptions};
 use std::io::{self, Write};
-#[cfg(target_arch = "x86_64")]
 use std::io::{Seek, SeekFrom};
 use std::num::Wrapping;
 use std::ops::Deref;
@@ -60,9 +58,7 @@ use std::path::PathBuf;
 use std::sync::{Arc, Mutex, RwLock};
 use std::{result, str, thread};
 use url::Url;
-use vm_memory::{Address, GuestAddress, GuestAddressSpace};
-#[cfg(target_arch = "x86_64")]
-use vm_memory::{Bytes, GuestMemoryMmap};
+use vm_memory::{Address, Bytes, GuestAddress, GuestAddressSpace, GuestMemoryMmap};
 use vm_migration::{
     Migratable, MigratableError, Pausable, Snapshot, SnapshotDataSection, Snapshottable,
     Transportable,
@@ -245,7 +241,6 @@ impl VmState {
 
 pub struct Vm {
     kernel: File,
-    #[cfg_attr(target_arch = "aarch64", allow(dead_code))]
     initramfs: Option<File>,
     threads: Vec<thread::JoinHandle<()>>,
     device_manager: Arc<Mutex<DeviceManager>>,
@@ -434,7 +429,6 @@ impl Vm {
         )
     }
 
-    #[cfg(target_arch = "x86_64")]
     fn load_initramfs(&mut self, guest_mem: &GuestMemoryMmap) -> Result<arch::InitramfsConfig> {
         let mut initramfs = self.initramfs.as_ref().unwrap();
         let size: usize = initramfs
@@ -631,6 +625,10 @@ impl Vm {
         let vcpu_mpidrs = self.cpu_manager.lock().unwrap().get_mpidrs();
         let guest_memory = self.memory_manager.lock().as_ref().unwrap().guest_memory();
         let mem = guest_memory.memory();
+        let initramfs_config = match self.initramfs {
+            Some(_) => Some(self.load_initramfs(mem.deref())?),
+            None => None,
+        };
 
         let device_info = &self
             .device_manager
@@ -671,7 +669,7 @@ impl Vm {
             self.cpu_manager.lock().unwrap().boot_vcpus() as u64,
             vcpu_mpidrs,
             device_info,
-            &None,
+            &initramfs_config,
             &pci_space,
         )
         .map_err(Error::ConfigureSystem)?;