kunit: tool: stop using a shell to run kernel under QEMU

Note: this potentially breaks custom qemu_configs if people are using
them! But the fix for them is simple, don't specify multiple arguments
in one string and don't add on a redundant ''.

It feels a bit iffy to be using a shell in the first place.

There's the usual shenanigans where people could pass in arbitrary shell
commands via --kernel_arg (since we're just adding '' around the
kernel_cmdline) or via a custom qemu_config.
This isn't too much of a concern given the nature of this script (and
the qemu_config file is in python, you can do w/e you want already).

But it does have some other drawbacks.

One example of a kunit-specific pain point:
If the relevant qemu binary is missing, we get output like this:
> /bin/sh: line 1: qemu-system-aarch64: command not found
This in turn results in our KTAP parser complaining about
missing/invalid KTAP, but we don't directly show the error!
It's even more annoying to debug when you consider --raw_output only
shows KUnit output by default, i.e. you need --raw_output=all to see it.

Whereas directly invoking the binary, Python will raise a
FileNotFoundError for us, which is a noisier but more clear.

Making this change requires
* splitting parameters like ['-m 256'] into ['-m', '256'] in
  kunit/qemu_configs/*.py
* change [''] to [] in kunit/qemu_configs/*.py since otherwise
  QEMU fails w/ 'Device needs media, but drive is empty'
* dropping explicit quoting of the kernel cmdline
* using shlex.quote() when we print what command we're running
  so the user can copy-paste and run it

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index 483f78e..1b9c492 100644 (file)
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -11,6 +11,7 @@ import importlib.util
 import logging
 import subprocess
 import os
+import shlex
 import shutil
 import signal
 import threading
@@ -118,16 +119,17 @@ class LinuxSourceTreeOperationsQemu(LinuxSourceTreeOperations):
                                '-nodefaults',
                                '-m', '1024',
                                '-kernel', kernel_path,
-                               '-append', '\'' + ' '.join(params + [self._kernel_command_line]) + '\'',
+                               '-append', ' '.join(params + [self._kernel_command_line]),
                                '-no-reboot',
                                '-nographic',
-                               '-serial stdio'] + self._extra_qemu_params
-               print('Running tests with:\n$', ' '.join(qemu_command))
-               return subprocess.Popen(' '.join(qemu_command),
-                                          stdin=subprocess.PIPE,
-                                          stdout=subprocess.PIPE,
-                                          stderr=subprocess.STDOUT,
-                                          text=True, shell=True, errors='backslashreplace')
+                               '-serial', 'stdio'] + self._extra_qemu_params
+               # Note: shlex.join() does what we want, but requires python 3.8+.
+               print('Running tests with:\n$', ' '.join(shlex.quote(arg) for arg in qemu_command))
+               return subprocess.Popen(qemu_command,
+                                       stdin=subprocess.PIPE,
+                                       stdout=subprocess.PIPE,
+                                       stderr=subprocess.STDOUT,
+                                       text=True, errors='backslashreplace')
 
 class LinuxSourceTreeOperationsUml(LinuxSourceTreeOperations):
        """An abstraction over command line operations performed on a source tree."""

diff --git a/tools/testing/kunit/qemu_configs/alpha.py b/tools/testing/kunit/qemu_configs/alpha.py
index 5d0c0cf..3ac846e 100644 (file)
--- a/tools/testing/kunit/qemu_configs/alpha.py
+++ b/tools/testing/kunit/qemu_configs/alpha.py
@@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
                           qemu_arch='alpha',
                           kernel_path='arch/alpha/boot/vmlinux',
                           kernel_command_line='console=ttyS0',
-                          extra_qemu_params=[''])
+                          extra_qemu_params=[])

diff --git a/tools/testing/kunit/qemu_configs/arm.py b/tools/testing/kunit/qemu_configs/arm.py
index b9c2a35..db21602 100644 (file)
--- a/tools/testing/kunit/qemu_configs/arm.py
+++ b/tools/testing/kunit/qemu_configs/arm.py
@@ -10,4 +10,4 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y''',
                           qemu_arch='arm',
                           kernel_path='arch/arm/boot/zImage',
                           kernel_command_line='console=ttyAMA0',
-                          extra_qemu_params=['-machine virt'])
+                          extra_qemu_params=['-machine', 'virt'])

diff --git a/tools/testing/kunit/qemu_configs/arm64.py b/tools/testing/kunit/qemu_configs/arm64.py
index 517c044..67d0406 100644 (file)
--- a/tools/testing/kunit/qemu_configs/arm64.py
+++ b/tools/testing/kunit/qemu_configs/arm64.py
@@ -9,4 +9,4 @@ CONFIG_SERIAL_AMBA_PL011_CONSOLE=y''',
                           qemu_arch='aarch64',
                           kernel_path='arch/arm64/boot/Image.gz',
                           kernel_command_line='console=ttyAMA0',
-                          extra_qemu_params=['-machine virt', '-cpu cortex-a57'])
+                          extra_qemu_params=['-machine', 'virt', '-cpu', 'cortex-a57'])

diff --git a/tools/testing/kunit/qemu_configs/i386.py b/tools/testing/kunit/qemu_configs/i386.py
index aed3ffd..52b80be 100644 (file)
--- a/tools/testing/kunit/qemu_configs/i386.py
+++ b/tools/testing/kunit/qemu_configs/i386.py
@@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
                           qemu_arch='x86_64',
                           kernel_path='arch/x86/boot/bzImage',
                           kernel_command_line='console=ttyS0',
-                          extra_qemu_params=[''])
+                          extra_qemu_params=[])

diff --git a/tools/testing/kunit/qemu_configs/powerpc.py b/tools/testing/kunit/qemu_configs/powerpc.py
index 35e9de2..7ec38d4 100644 (file)
--- a/tools/testing/kunit/qemu_configs/powerpc.py
+++ b/tools/testing/kunit/qemu_configs/powerpc.py
@@ -9,4 +9,4 @@ CONFIG_HVC_CONSOLE=y''',
                           qemu_arch='ppc64',
                           kernel_path='vmlinux',
                           kernel_command_line='console=ttyS0',
-                          extra_qemu_params=['-M pseries', '-cpu power8'])
+                          extra_qemu_params=['-M', 'pseries', '-cpu', 'power8'])

diff --git a/tools/testing/kunit/qemu_configs/riscv.py b/tools/testing/kunit/qemu_configs/riscv.py
index 9e52808..b882fde 100644 (file)
--- a/tools/testing/kunit/qemu_configs/riscv.py
+++ b/tools/testing/kunit/qemu_configs/riscv.py
@@ -26,6 +26,6 @@ CONFIG_SERIAL_EARLYCON_RISCV_SBI=y''',
                           kernel_path='arch/riscv/boot/Image',
                           kernel_command_line='console=ttyS0',
                           extra_qemu_params=[
-                                          '-machine virt',
-                                          '-cpu rv64',
-                                          '-bios opensbi-riscv64-generic-fw_dynamic.bin'])
+                                          '-machine', 'virt',
+                                          '-cpu', 'rv64',
+                                          '-bios', 'opensbi-riscv64-generic-fw_dynamic.bin'])

diff --git a/tools/testing/kunit/qemu_configs/s390.py b/tools/testing/kunit/qemu_configs/s390.py
index e310bd5..98fa4fb 100644 (file)
--- a/tools/testing/kunit/qemu_configs/s390.py
+++ b/tools/testing/kunit/qemu_configs/s390.py
@@ -10,5 +10,5 @@ CONFIG_MODULES=y''',
                           kernel_path='arch/s390/boot/bzImage',
                           kernel_command_line='console=ttyS0',
                           extra_qemu_params=[
-                                          '-machine s390-ccw-virtio',
-                                          '-cpu qemu',])
+                                          '-machine', 's390-ccw-virtio',
+                                          '-cpu', 'qemu',])

diff --git a/tools/testing/kunit/qemu_configs/sparc.py b/tools/testing/kunit/qemu_configs/sparc.py
index 27f474e..e975c43 100644 (file)
--- a/tools/testing/kunit/qemu_configs/sparc.py
+++ b/tools/testing/kunit/qemu_configs/sparc.py
@@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
                           qemu_arch='sparc',
                           kernel_path='arch/sparc/boot/zImage',
                           kernel_command_line='console=ttyS0 mem=256M',
-                          extra_qemu_params=['-m 256'])
+                          extra_qemu_params=['-m', '256'])

diff --git a/tools/testing/kunit/qemu_configs/x86_64.py b/tools/testing/kunit/qemu_configs/x86_64.py
index 77ab1ae..dc79490 100644 (file)
--- a/tools/testing/kunit/qemu_configs/x86_64.py
+++ b/tools/testing/kunit/qemu_configs/x86_64.py
@@ -7,4 +7,4 @@ CONFIG_SERIAL_8250_CONSOLE=y''',
                           qemu_arch='x86_64',
                           kernel_path='arch/x86/boot/bzImage',
                           kernel_command_line='console=ttyS0',
-                          extra_qemu_params=[''])
+                          extra_qemu_params=[])