chore: update CI, docs, and justfile for aarch64

- Add concurrency group to cancel stale CI runs
- Gate KVM setup on X64 runners
- Gate run-guest on X64 (no host support on ARM yet)
- Update README to mention aarch64 target
- Use arch() in justfile for target-independent paths

Signed-off-by: Ludvig Liljenberg <4257730+ludfjig@users.noreply.github.com>

Author: ludfjig

.github/workflows/ci.yml

@@ -11,6 +11,11 @@ on:
     branches: [main]
   workflow_call:
 
+# Cancels old running job if a new one is triggered (e.g. by a push onto the same branch).
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 env:
   CARGO_TERM_COLOR: always
 
@@ -27,7 +32,7 @@ jobs:
     - uses: Swatinem/rust-cache@v2
     - uses: extractions/setup-just@v3
     - name: Enable kvm
-      if: runner.os == 'Linux'
+      if: runner.os == 'Linux' && runner.arch == 'X64'
       run: |
         echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
         sudo udevadm control --reload-rules
@@ -39,6 +44,7 @@ jobs:
       shell: bash
       run: just build-guest
     - name: Run example
+      if: runner.arch == 'X64'
       shell: bash
       run: just run-guest
 

README.md

@@ -83,7 +83,7 @@ Then to build the hyperlight guest binary, run
 cargo hyperlight build --release
 ```
 
-Your binary will be built for the `x86_64-hyperlight-none` target by default, and placed in `target/x86_64-hyperlight-none/release/guest`.
+Your binary will be built for the `x86_64-hyperlight-none` target (or `aarch64-hyperlight-none` on ARM) by default, and placed in `target/<arch>-hyperlight-none/release/guest`.
 
 There's no need for any extra configuration, the command will take care of everything.
 

justfile

@@ -22,4 +22,4 @@ build-guest:
     cargo hyperlight build --manifest-path ./examples/guest/Cargo.toml
 
 run-guest: build-guest
-    cargo run --manifest-path ./examples/host/Cargo.toml -- ./target/x86_64-hyperlight-none/debug/guest
+    cargo run --manifest-path ./examples/host/Cargo.toml -- ./target/{{arch()}}-hyperlight-none/debug/guest