boot-qemu.py: Add support for booting ARCH=arm kernels via EFI

arm kernels can be booted via EFI in the same manner as arm64. Refactor
the current EFI image creation logic into its own class so that
arm32_v7 and arm64 can share most of the logic, just with different
files.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Author: nathanchance

boot-qemu.py

@@ -319,6 +319,31 @@ def run(self):
             self._run_fg()
 
 
+class ARMEFIQEMURunner(QEMURunner):
+
+    def _setup_efi(self, possible_locations):
+        # Sizing the images to 64M is recommended by "Prepare the firmware" section at
+        # https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/docs/qemu/qemu-arm64-howto.html
+        efi_img_size = 64 * 1024 * 1024  # 64M
+
+        usr_share = Path('/usr/share')
+
+        aavmf = utils.find_first_file(usr_share, possible_locations)
+
+        self._efi_img = Path(utils.BOOT_UTILS, 'images', self._initrd_arch,
+                             'efi.img')
+        # This file is in /usr/share, so it must be copied in order to be
+        # modified.
+        shutil.copyfile(aavmf, self._efi_img)
+        with self._efi_img.open(mode='r+b') as file:
+            file.truncate(efi_img_size)
+
+        self._efi_vars = self._efi_img.with_name('efivars.img')
+        self._efi_vars.unlink(missing_ok=True)
+        with self._efi_vars.open(mode='xb') as file:
+            file.truncate(efi_img_size)
+
+
 class ARMQEMURunner(QEMURunner):
 
     def __init__(self):
@@ -359,11 +384,12 @@ def __init__(self):
         self._machine = 'romulus-bmc'
 
 
-class ARMV7QEMURunner(ARMQEMURunner):
+class ARMV7QEMURunner(ARMQEMURunner, ARMEFIQEMURunner):
 
     def __init__(self):
         super().__init__()
 
+        self.supports_efi = True
         self.use_kvm = self._can_use_kvm()
 
         self.cmdline += ['console=ttyAMA0', 'earlycon']
@@ -386,14 +412,20 @@ def _can_use_kvm(self):
         return self._have_dev_kvm_access()
 
     def run(self):
+        if self.efi:
+            aavmf_locations = [
+                Path('edk2/arm/QEMU_EFI.fd'),  # Arch Linux, Fedora
+            ]
+            self._setup_efi(aavmf_locations)
+
         if self.use_kvm:
             self._kvm_cpu.append('aarch64=off')
             self._qemu_arch = 'aarch64'
 
         super().run()
 
 
-class ARM64QEMURunner(QEMURunner):
+class ARM64QEMURunner(ARMEFIQEMURunner):
 
     def __init__(self):
         super().__init__()
@@ -429,34 +461,6 @@ def _get_cpu_val(self):
 
         return cpu
 
-    def _setup_efi(self):
-        # Sizing the images to 64M is recommended by "Prepare the firmware" section at
-        # https://mirrors.edge.kernel.org/pub/linux/kernel/people/will/docs/qemu/qemu-arm64-howto.html
-        efi_img_size = 64 * 1024 * 1024  # 64M
-
-        usr_share = Path('/usr/share')
-
-        aavmf_locations = [
-            Path('edk2/aarch64/QEMU_EFI.silent.fd'),  # Fedora
-            Path('edk2/aarch64/QEMU_EFI.fd'),  # Arch Linux (current)
-            Path('edk2-armvirt/aarch64/QEMU_EFI.fd'),  # Arch Linux (old)
-            Path('qemu-efi-aarch64/QEMU_EFI.fd'),  # Debian and Ubuntu
-        ]
-        aavmf = utils.find_first_file(usr_share, aavmf_locations)
-
-        self._efi_img = Path(utils.BOOT_UTILS, 'images', self._initrd_arch,
-                             'efi.img')
-        # This file is in /usr/share, so it must be copied in order to be
-        # modified.
-        shutil.copyfile(aavmf, self._efi_img)
-        with self._efi_img.open(mode='r+b') as file:
-            file.truncate(efi_img_size)
-
-        self._efi_vars = self._efi_img.with_name('efivars.img')
-        self._efi_vars.unlink(missing_ok=True)
-        with self._efi_vars.open(mode='xb') as file:
-            file.truncate(efi_img_size)
-
     def run(self):
         machine = ['virt', 'gic-version=max']
 
@@ -471,7 +475,13 @@ def run(self):
         self._qemu_args += ['-machine', ','.join(machine)]
 
         if self.efi:
-            self._setup_efi()
+            aavmf_locations = [
+                Path('edk2/aarch64/QEMU_EFI.silent.fd'),  # Fedora
+                Path('edk2/aarch64/QEMU_EFI.fd'),  # Arch Linux (current)
+                Path('edk2-armvirt/aarch64/QEMU_EFI.fd'),  # Arch Linux (old)
+                Path('qemu-efi-aarch64/QEMU_EFI.fd'),  # Debian and Ubuntu
+            ]
+            self._setup_efi(aavmf_locations)
 
         super().run()