kunit: tool: Don't download risc-v opensbi firmware with wget

When running a RISC-V test kernel under QEMU, we need an OpenSBI BIOS
file. In the original QEMU support patchset, kunit_tool would optionally
download this file from GitHub if it didn't exist, using wget.

These days, it can usually be found in the distro's qemu-system-riscv
package, and is located in /usr/share/qemu on all the distros I tried
(Debian, Arch, OpenSUSE). Use this file, and thereby don't do any
downloading in kunit_tool.

In addition, we used to shell out to whatever 'wget' was in the path,
which could have potentially been used to trick the developer into
running another binary. By not using wget at all, we nicely sidestep
this issue.

Cc: Xu Panda <xu.panda@zte.com.cn>
Fixes: 87c9c1631788 ("kunit: tool: add support for QEMU")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: David Gow <davidgow@google.com>
Tested-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: tool: update riscv QEMU config with new serial dependency

The config for the serial console for riscv,
CONFIG_SERIAL_EARLYCON_RISCV_SBI, added a dependency,
CONFIG_RISCV_SBI_V01, at some point, so add that in to the base arch
config.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

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>

kunit: tool: add support for QEMU

Add basic support to run QEMU via kunit_tool. Add support for i386,
x86_64, arm, arm64, and a bunch more.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: David Gow <davidgow@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>