Re: [PATCH 1/2] tests/acceptance: Add PVH boot test

[Wainer dos Santos Moschetta]

On 12/6/19 2:54 PM, Cleber Rosa wrote:
> On Fri, Dec 06, 2019 at 09:00:11AM -0500, Wainer dos Santos Moschetta wrote:
> > QEMU 4.0 onward is able to boot an uncompressed kernel
> > image by using the x86/HVM direct boot ABI. It needs
> > Linux >= 4.21 built with CONFIG_PVH=y.
> >
> > This introduces an acceptance test which checks an
> > uncompressed Linux kernel image boots properly.
> >
> > Signed-off-by: Wainer dos Santos Moschetta <address@hidden>
> > ---
> >   tests/acceptance/pvh.py | 48 +++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 48 insertions(+)
> >   create mode 100644 tests/acceptance/pvh.py
> >
> > diff --git a/tests/acceptance/pvh.py b/tests/acceptance/pvh.py
> > new file mode 100644
> > index 0000000000..c68489c273
> > --- /dev/null
> > +++ b/tests/acceptance/pvh.py
> > @@ -0,0 +1,48 @@
> > +# Copyright (c) 2019 Red Hat, Inc.
> > +#
> > +# Author:
> > +#  Wainer dos Santos Moschetta <address@hidden>
> > +#
> > +# This work is licensed under the terms of the GNU GPL, version 2 or
> > +# later.  See the COPYING file in the top-level directory.
> > +
> > +"""
> > +x86/HVM direct boot acceptance tests.
> > +"""
> > +
> > +from avocado.utils.kernel import KernelBuild
> > +from avocado_qemu import Test
> > +from avocado_qemu import wait_for_console_pattern
> > +
> > +
> > +class Pvh(Test):
> > +    """
> > +    Test suite for x86/HVM direct boot feature.
> > +
> > +    :avocado: tags=slow,arch=x86_64,machine=q35
> > +    """
> > +    def test_boot_vmlinux(self):
> > +        """
> > +        Boot uncompressed kernel image.
> > +        """
> > +        # QEMU can boot a vmlinux image for kernel >= 4.21 built
> > +        # with CONFIG_PVH=y
> > +        kernel_version = '5.4.1'
> > +        kbuild = KernelBuild(kernel_version, work_dir=self.workdir)
> > +        try:
> > +            kbuild.download()
> > +            kbuild.uncompress()
> > +            kbuild.configure(targets=['defconfig', 'kvmconfig'],
> > +                             extra_configs=['CONFIG_PVH=y'])
> I'm aware of the reason why this uses APIs not fulfilled by
> tests/requirements.txt, but, for the general public reviewing/testing
> code with extra requirements, it's a good idea to bump the
> requirements to a version that fulfills the requirement, and comment
> out clearly on the temporary nature of the change (marking the patch).

Good idea, thanks for the tip.

> For instance, for this requirement, we could have:
>
> diff --git a/tests/requirements.txt b/tests/requirements.txt
> index a2a587223a..5498d67bc1 100644
> --- a/tests/requirements.txt
> +++ b/tests/requirements.txt
> @@ -1,4 +1,5 @@
>   # Add Python module requirements, one per line, to be installed
>   # in the tests/venv Python virtual environment. For more info,
>   # refer to: https://pip.pypa.io/en/stable/user_guide/#id1
> -avocado-framework==72.0
> +# [REMOVE ME] use post 73.0 Avocado containing the new kernel build APIs
> +-e 
> git+https://github.com/avocado-framework/avocado@d6fb24edcf847f09c312b55df3c674c64c79793e#egg=avocado_framework
>
> This will not only help people to test it, but should also make
> it work transparently on CI.

True. It could had helped me to check the missing packages on Travis to 
build the kernel. I'm ashamed to tell how I did it. :)

> > +            kbuild.build()
> As stated in my response to the cover letter, I think we need to move
> this elsewhere.  The *very* minimum is to have this in a setUp()
> method, but we should strongly consider other solutions.

On the proposed implementation the kernel is built only once and only 
for this test case. If I move the code to setUp() it will attempt to 
build the vmlinux for every case even when not needed (suppose I add a 
'boot not CONFIG_PVH vmlinux to check it properly handle error' case 
which uses distro's kernel). Unless I put a guard like 'do not build if 
already present' which IMHO is weird. In other words, IMHO setUp() 
should hold only code that is share-able across cases.

> > +        except:
> > +            self.cancel("Unable to build vanilla kernel %s" % kernel_version)
> > +
> > +        self.vm.set_machine('q35')
> > +        self.vm.set_console()
> > +        kernel_command_line = 'printk.time=0 console=ttyS0'
> > +        self.vm.add_args('-kernel', kbuild.vmlinux,
> > +                         '-append', kernel_command_line)
> And just for being thorough (and purist? idealistic? Utopian? :), if
> we stop and think about it, the following two lines are really what
> this test is all about.  Everything else should be the test's setup.
>
> I'm not arguing in favor of being radical and reject anything that is
> not perfect, but just reminding ourselves (myself very much included)
> of this general direction.

IMHO we should merge tests which are "good enough" then interactively 
improve them. At least they will run with some frequency and eventually 
catch regressions while infra bits are improved. Now, what's 'good 
enough' for an acceptance test? Perhaps a test that run consistently?

> Cheers,
> - Cleber.
>
> > +        self.vm.launch()
> > +        wait_for_console_pattern(self, 'Kernel command line: %s' %
> > +                                 kernel_command_line)
> > --
> > 2.21.0