ci: add a workflow for bootloader

Signed-off-by: Changyuan Lyu <changyuanl@google.com>

Author: Lencerf

.github/workflows/bootloader.yml

@@ -0,0 +1,41 @@
+name: Build Bootloader
+
+on:
+  workflow_dispatch:
+  workflow_call:
+  pull_request:
+    branches: ["main"]
+    paths:
+      - bootloader/**
+      - .github/workflows/bootloader.yml
+
+jobs:
+  build_bootloader:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-latest
+            arch: x86_64
+          - os: ubuntu-24.04-arm
+            arch: aarch64
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+      - uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6.2.0
+        with:
+          go-version: stable
+          cache-dependency-path: "**/go.sum"
+      - name: Install LLVM and Clang
+        uses: KyleMayes/install-llvm-action@98e68e10c96dffcb7bfed8b2144541a66b49aa02 # v2.0.8
+        with:
+          version: "20"
+      - name: Install dependencies
+        run: sudo apt-get update && sudo apt-get install -y libelf-dev
+      - name: Build bootloader
+        run: ARCH=${{ matrix.arch }} ./bootloader/build.sh
+      - name: Upload artifact
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
+        with:
+          name: kernel-${{ matrix.arch }}
+          path: target/bootloader-${{ matrix.arch }}/kernel-${{ matrix.arch }}

bootloader/build.sh

@@ -14,7 +14,7 @@ function fetch_source() {
     pushd target
 
     echo "Fetching Linux source..."
-    wget ${LINUX_SRC} -O linux.tar.xz
+    wget -q -O linux.tar.xz ${LINUX_SRC}
     tar xf linux.tar.xz
     mv linux-* linux
 
@@ -60,7 +60,9 @@ function build_linux() {
     echo "Building Linux kernel..."
     make ${vars[@]}
 
-    echo "Image: ${TARGET_DIR}/${image}"
+    mv ${TARGET_DIR}/${image} ${TARGET_DIR}/kernel-${ARCH}
+
+    echo "Image: ${TARGET_DIR}/kernel-${ARCH}"
 }
 
 

docs/cloud-image.md

@@ -33,7 +33,7 @@ bootloader/build.sh
 ```
 
 The Alioth binary will be located at `target/release/alioth`, and the bootloader
-kernel image at `target/bootloader-x86_64/linux/arch/x86/boot/bzImage`.
+kernel image at `target/bootloader-x86_64/kernel-x86_64`.
 
 ## Preparing Disk Images
 
@@ -82,7 +82,7 @@ Run the following command to start the VM.
 ```bash
 ./alioth -l info --log-to-file boot \
     -m size=4G -p count=4 \
-    -k ./bzImage \
+    -k ./kernel-x86_64 \
     --entropy \
     --pvpanic \
     --blk file,path=Fedora-Cloud-Base-Generic-43-1.6.x86_64.raw \