build: 🛠 Set machine ID for QEMU versions after 6.2.0

Work around ancient QEMU versions on CI boxes.

.github/workflows/build.yml

@@ -101,8 +101,13 @@ jobs:
     - name: 'Build kernel'
       run: cargo make build
 
-    - name: 'Run tests'
+    - name: 'Run tests (macOS)'
       run: cargo make test
+      if: runner.os == 'macOS'
+
+    - name: 'Run tests (other OSes)'
+      run: env QEMU_MACHINE=raspi3 cargo make test
+      if: runner.os != 'macOS'
 
   check_formatting:
     name: "Check Formatting"

Makefile.toml

@@ -22,6 +22,8 @@ TARGET_BOARD = { value = "rpi4", condition = { env_not_set = ["TARGET_BOARD"] }
 
 # AArch64 QEMU binary
 QEMU = { value = "qemu-system-aarch64", condition = { env_not_set = ["QEMU"] } }
+# QEMU machine type, defaults to raspi3b but CI runners override it due to ancient QEMU versions they use.
+QEMU_MACHINE = { value = "raspi3b", condition = { env_not_set = ["QEMU_MACHINE"] } }
 
 # An aarch64-enabled GDB
 GDB = { value = "/usr/local/opt/gdb/HEAD-a2c58332-aarch64/bin/aarch64-unknown-elf-gdb", condition = { env_not_set = ["GDB"] } }
@@ -57,7 +59,8 @@ QEMU_CONTAINER_CMD = "qemu-system-aarch64"
 # Could additionally use -nographic to disable GUI -- this shall be useful for automated tests.
 #
 # -d in_asm,unimp,int
-QEMU_OPTS = "-M raspi3 -d int -semihosting"
+# QEMU has renamed the RasPi machines since version 6.2.0, use just `raspi3` for previous versions.
+QEMU_OPTS = "-M ${QEMU_MACHINE} -d int -semihosting"
 QEMU_SERIAL_OPTS = "-serial null -serial stdio"
 QEMU_TESTS_OPTS = "-nographic"
 # For gdb connection: