Allow booting cpio images in qemu

Let's add back some form of direct linux boot by allowing to boot
cpio images. To make this work, either the user has to pass -kernel
or a kernel has to be installed inside the cpio, which we'll copy
out and use as the -kernel argument.

diff --git a/mkosi/__init__.py b/mkosi/__init__.py
index aa5e867ac4a5d2dad5cba10a6aaae96407db6af2..11dbb173ec4ffdb5f53a1a7935eacead692a80de 100644 (file)
--- a/mkosi/__init__.py
+++ b/mkosi/__init__.py
@@ -715,6 +715,10 @@ def install_unified_kernel(state: MkosiState, roothash: Optional[str]) -> None:
     if state.for_cache or state.config.bootable is False:
         return
 
+    for kver, kimg in gen_kernel_images(state):
+        copy_path(state.root / kimg, state.staging / state.config.output_split_kernel.name)
+        break
+
     if state.config.output_format == OutputFormat.cpio and state.config.bootable is None:
         return
 
@@ -793,10 +797,10 @@ def install_unified_kernel(state: MkosiState, roothash: Optional[str]) -> None:
 
             run(cmd)
 
-            if not state.staging.joinpath(state.config.output_split_kernel.name).exists():
-                copy_path(boot_binary, state.staging / state.config.output_split_kernel.name)
+            if not state.staging.joinpath(state.config.output_split_uki.name).exists():
+                copy_path(boot_binary, state.staging / state.config.output_split_uki.name)
 
-    if state.config.bootable is True and not state.staging.joinpath(state.config.output_split_kernel.name).exists():
+    if state.config.bootable is True and not state.staging.joinpath(state.config.output_split_uki.name).exists():
         die("A bootable image was requested but no kernel was found")
 
 
@@ -970,6 +974,12 @@ def unlink_output(config: MkosiConfig) -> None:
                     unlink_try_hard(p)
         unlink_try_hard(config.output_split_kernel)
 
+        if config.output_split_uki.parent.exists():
+            for p in config.output_split_uki.parent.iterdir():
+                if p.name.startswith(config.output_split_uki.name):
+                    unlink_try_hard(p)
+        unlink_try_hard(config.output_split_uki)
+
         if config.nspawn_settings is not None:
             unlink_try_hard(config.output_nspawn_settings)
 
@@ -1085,17 +1095,9 @@ def load_credentials(args: argparse.Namespace) -> dict[str, str]:
 
 
 def load_kernel_command_line_extra(args: argparse.Namespace) -> list[str]:
-    cmdline = []
-
-    for s in args.kernel_command_line_extra:
-        key, sep, value = s.partition("=")
-        if " " in value:
-            value = f'"{value}"'
-        cmdline += [key if not sep else f"{key}={value}"]
-
     columns, lines = shutil.get_terminal_size()
 
-    cmdline += [
+    cmdline = [
         f"systemd.tty.term.hvc0={os.getenv('TERM', 'vt220')}",
         f"systemd.tty.columns.hvc0={columns}",
         f"systemd.tty.rows.hvc0={lines}",
@@ -1105,6 +1107,15 @@ def load_kernel_command_line_extra(args: argparse.Namespace) -> list[str]:
         "console=hvc0",
     ]
 
+    if args.output_format == OutputFormat.cpio:
+        cmdline += ["rd.systemd.unit=default.target"]
+
+    for s in args.kernel_command_line_extra:
+        key, sep, value = s.partition("=")
+        if " " in value:
+            value = f'"{value}"'
+        cmdline += [key if not sep else f"{key}={value}"]
+
     return cmdline
 
 
@@ -1122,7 +1133,6 @@ def load_args(args: argparse.Namespace) -> MkosiConfig:
         OutputFormat.directory,
         OutputFormat.subvolume,
         OutputFormat.tar,
-        OutputFormat.cpio,
     ):
         die("Directory, subvolume, tar, cpio, and plain squashfs images cannot be booted in qemu.")
 
@@ -1225,10 +1235,6 @@ def load_args(args: argparse.Namespace) -> MkosiConfig:
         if args.compress_output != Compression.none:
             die(f"Sorry, can't {opname} with a compressed image.")
 
-    if args.verb == Verb.qemu:
-        if not args.output_format == OutputFormat.disk:
-            die("Sorry, can't boot non-disk images with qemu.")
-
     if args.repo_dirs and not (is_dnf_distribution(args.distribution) or args.distribution == Distribution.arch):
         die("--repo-dir is only supported on DNF based distributions and Arch")
 
@@ -2242,6 +2248,15 @@ def run_qemu(config: MkosiConfig) -> None:
             fname = config.output_compressed
 
         # Debian images fail to boot with virtio-scsi, see: https://github.com/systemd/mkosi/issues/725
+        if config.output_format == OutputFormat.cpio:
+            kernel = (config.output_dir or Path.cwd()) / config.output_split_kernel
+            if not kernel.exists() and "-kernel" not in config.cmdline:
+                die("No kernel found, please install a kernel in the cpio or provide a -kernel argument to mkosi qemu")
+            cmdline += [
+                "-kernel", kernel,
+                "-initrd", fname,
+                "-append", " ".join(config.kernel_command_line + config.kernel_command_line_extra),
+            ]
         if config.distribution == Distribution.debian:
             cmdline += [
                 "-drive",

diff --git a/mkosi/backend.py b/mkosi/backend.py
index 0e452d78d06d85e8f64a15f68b5ce52b875e44bc..5a70728e4a02e2cb598165af96048316b8115020 100644 (file)
--- a/mkosi/backend.py
+++ b/mkosi/backend.py
@@ -294,9 +294,13 @@ class MkosiConfig:
         return self.architecture == platform.machine()
 
     @property
-    def output_split_kernel(self) -> Path:
+    def output_split_uki(self) -> Path:
         return build_auxiliary_output_path(self, ".efi")
 
+    @property
+    def output_split_kernel(self) -> Path:
+        return build_auxiliary_output_path(self, ".vmlinuz")
+
     @property
     def output_nspawn_settings(self) -> Path:
         return build_auxiliary_output_path(self, ".nspawn")
@@ -331,6 +335,7 @@ class MkosiConfig:
     def output_paths(self) -> tuple[Path, ...]:
         return (
             self.output,
+            self.output_split_uki,
             self.output_split_kernel,
             self.output_nspawn_settings,
             self.output_checksum,