Minor refactoring of QemuOptions

Make the qemu_arch_sufffix member private and fix the spelling error.
Also improve get_qemu_binary() to be able to pass a list
of search dirs instead of always using $PATH

Author: arichardson

pycheribuild/boot_cheribsd/__init__.py

@@ -1524,7 +1524,7 @@ def _main(
     else:
         args.qemu_cmd = qemu_options.get_qemu_binary()
         if args.qemu_cmd is None:
-            failure("ERROR: Cannot find QEMU binary for target ", qemu_options.qemu_arch_sufffix, exit=True)
+            failure("ERROR: Cannot find QEMU binary for target ", qemu_options.xtarget, exit=True)
 
     global INTERACT_ON_KERNEL_PANIC  # noqa: PLW0603
     if args.interact_on_kernel_panic:

pycheribuild/projects/run_qemu.py

@@ -110,21 +110,17 @@ def setup(self, launch):
         assert launch.use_qemu == QEMUType.SYSTEM or launch.use_qemu == QEMUType.DEFAULT, (
             "Unexpected use_qemu for lazy binary location: " + str(launch.use_qemu)
         )
-        binary_name = "qemu-system-" + launch.qemu_options.qemu_arch_sufffix
-        if (launch.config.qemu_bindir / binary_name).is_file() and launch.use_qemu != QEMUType.SYSTEM:
+        qemu_binary = launch.qemu_options.get_qemu_binary(search_dirs=[launch.config.qemu_bindir])
+        if qemu_binary is not None and qemu_binary.is_file() and launch.use_qemu != QEMUType.SYSTEM:
             # Only CHERI QEMU supports more than one SMB share
             self._can_provide_src_via_smb = True
-            self._binary = launch.config.qemu_bindir / binary_name
         else:
-            # Only CHERI QEMU supports more than one SMB share; conservatively
-            # guess what kind of QEMU this is
+            # Only CHERI QEMU supports more than one SMB share; conservatively guess what kind of QEMU this is
             self._can_provide_src_via_smb = launch.crosscompile_target.is_hybrid_or_purecap_cheri()
-            launch.check_required_system_tool(binary_name)
-            binary_path = shutil.which(binary_name)
-            if not binary_path:
-                launch.fatal("Could not find system QEMU", binary_name)
-                binary_path = "/could/not/find/qemu"
-            self._binary = Path(binary_path)
+            if qemu_binary is None:
+                launch.fatal("Could not find system QEMU for target:", launch.qemu_options.xtarget)
+                qemu_binary = Path("/could/not/find/qemu")
+        self._binary = qemu_binary
 
 
 class LaunchQEMUBase(SimpleProject):
@@ -243,8 +239,8 @@ def targets_reset(cls):
         cls._cached_chosen_qemu = None
 
     @classmethod
-    def get_chosen_qemu(cls, config: CheriConfig):
-        if cls._cached_chosen_qemu:
+    def get_chosen_qemu(cls, config: CheriConfig) -> ChosenQEMU:
+        if cls._cached_chosen_qemu is not None:
             return cls._cached_chosen_qemu
 
         xtarget = cls.get_crosscompile_target()
@@ -273,8 +269,7 @@ def get_chosen_qemu(cls, config: CheriConfig):
             assert False, "Unknown target " + str(xtarget)
 
         if cls.use_qemu == QEMUType.CUSTOM:
-            # Only CHERI QEMU supports more than one SMB share; conservatively
-            # guess what kind of QEMU this is
+            # Only CHERI QEMU supports more than one SMB share; conservatively guess what kind of QEMU this is
             can_provide_src_via_smb = xtarget.is_hybrid_or_purecap_cheri()
             if not cls.custom_qemu_path:
                 fatal_error(

pycheribuild/qemu_utils.py

@@ -47,7 +47,7 @@ def __init__(self, xtarget: CrossCompileTarget, want_debugger=False) -> None:
         self.memory_size = "2048"
         self.has_default_nic = False
         if xtarget.is_hybrid_or_purecap_cheri([CPUArchitecture.AARCH64]):
-            self.qemu_arch_sufffix = "morello"
+            self._qemu_arch_suffix = "morello"
             self.can_boot_kernel_directly = False  # boot from disk
             # XXX: Use a CHERI-aware firmware. EL3 is disabled by default for
             # virt, so CPTR_EL3 doesn't exist and CheriBSD can enable
@@ -56,19 +56,19 @@ def __init__(self, xtarget: CrossCompileTarget, want_debugger=False) -> None:
             self.machine_flags = ["-M", "virt,gic-version=3", "-cpu", "morello", "-bios", "edk2-aarch64-code.fd"]
         elif xtarget.is_mips(include_purecap=True):
             # Note: we always use the CHERI QEMU
-            self.qemu_arch_sufffix = "mips64cheri128"
+            self._qemu_arch_suffix = "mips64cheri128"
             self.machine_flags = ["-M", "malta"]
             self.virtio_disk = False  # broken for MIPS?
             self.can_boot_kernel_directly = True
             self.has_default_nic = True  # MALTA board has a default pcnet at 0x0b
         elif xtarget.is_riscv(include_purecap=True):
             # Note: we always use the CHERI QEMU
-            self.qemu_arch_sufffix = "riscv32cheri" if xtarget.is_riscv32(include_purecap=True) else "riscv64cheri"
+            self._qemu_arch_suffix = "riscv32cheri" if xtarget.is_riscv32(include_purecap=True) else "riscv64cheri"
             self.machine_flags = ["-M", "virt"]
             self.can_boot_kernel_directly = True
         elif xtarget.is_any_x86():
             # We boot i386 FreeBSD in a x86_64 QEMU. This avoids having to build another version of QEMU.
-            self.qemu_arch_sufffix = "x86_64"
+            self._qemu_arch_suffix = "x86_64"
             self.can_boot_kernel_directly = False  # boot from disk
             # Try to use KVM instead of TCG if possible to speed up emulation
             if not want_debugger:
@@ -83,11 +83,11 @@ def __init__(self, xtarget: CrossCompileTarget, want_debugger=False) -> None:
             # We have to use the ancient default instead to avoid kernel panics.
             # See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=253617 for details.
         elif xtarget.is_aarch64(include_purecap=False):
-            self.qemu_arch_sufffix = "aarch64"
+            self._qemu_arch_suffix = "aarch64"
             self.can_boot_kernel_directly = False  # boot from disk
             self.machine_flags = ["-M", "virt,gic-version=3", "-cpu", "cortex-a72", "-bios", "edk2-aarch64-code.fd"]
         elif xtarget.is_arm32(include_purecap=False):
-            self.qemu_arch_sufffix = "arm"
+            self._qemu_arch_suffix = "arm"
             self.can_boot_kernel_directly = False  # boot from disk
             self.machine_flags = ["-M", "virt", "-cpu", "cortex-15"]
         else:
@@ -156,9 +156,15 @@ def user_network_args(self, extra_options) -> "list[str]":
         network_device_kind = self._qemu_network_config()[0]
         return ["-device", network_device_kind + ",netdev=net0", "-netdev", "user,id=net0" + extra_options]
 
-    def get_qemu_binary(self) -> "Optional[Path]":
-        found_in_path = shutil.which("qemu-system-" + self.qemu_arch_sufffix)
-        return Path(found_in_path) if found_in_path is not None else None
+    def get_qemu_binary(self, search_dirs: "Optional[list[Path]]" = None) -> "Optional[Path]":
+        if search_dirs is None:
+            found_in_path = shutil.which("qemu-system-" + self._qemu_arch_suffix)
+            return Path(found_in_path) if found_in_path is not None else None
+        for d in search_dirs:
+            candidate = d / f"qemu-system-{self._qemu_arch_suffix}"
+            if candidate.exists():
+                return candidate
+        return None
 
     def get_commandline(
         self,