Re: [PATCH] acpi/tests/bios-tables-test: add an environment variable for iasl location

["Alex Bennée" <alex.bennee@linaro.org>]

Ani Sinha <anisinha@redhat.com> writes:

>> On 17-May-2023, at 8:06 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
>> 
>> On Wed, May 17, 2023 at 07:57:53PM +0530, Ani Sinha wrote:
>>> 
>>> 
>>>> On 17-May-2023, at 7:47 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
>>>> 
>>>> On Wed, May 17, 2023 at 05:37:51PM +0530, Ani Sinha wrote:
>>>>> Currently the meson based QEMU build process locates the iasl binary from the
>>>>> current PATH and other locations [1] and uses that to set CONFIG_IASL which is
>>>>> then used by the test.
>>>>> 
>>>>> This has two disadvantages:
>>>>> - If iasl was not previously installed in the PATH, one has to install iasl
>>>>>  and rebuild QEMU in order to pick up the iasl location. One cannot simply
>>>>>  use the existing bios-tables-test binary because CONFIG_IASL is only set
>>>>>  during the QEMU build time by meson and then bios-tables-test has to be
>>>>>  rebuilt with CONFIG_IASL set in order to use iasl.

Usually we work the other way by checking at configure time and skipping
the feature if the prerequisites are not in place. We do this with gdb:

  ../../configure --gdb=/home/alex/src/tools/binutils-gdb.git/builds/all/install/bin/gdb

which checks gdb is at least new enough to support the features we need:

  if test -n "$gdb_bin"; then
      gdb_version=$($gdb_bin --version | head -n 1)
      if version_ge ${gdb_version##* } 9.1; then
          echo "HAVE_GDB_BIN=$gdb_bin" >> $config_host_mak
          gdb_arches=$("$source_path/scripts/probe-gdb-support.py" $gdb_bin)
      else
          gdb_bin=""
      fi
  fi

>>>>> - Sometimes, the stock iasl that comes with distributions is simply not good
>>>>>  enough because it does not support the latest ACPI changes - newly
>>>>>  introduced tables or new table attributes etc. In order to test ACPI code
>>>>>  in QEMU, one has to clone the latest acpica upstream repository and
>>>>>  rebuild iasl in order to get support for it. In those cases, one may want
>>>>>  the test to use the iasl binary from a non-standard location.

I think configure should be checking if iasl is new enough and reporting
to the user at configure time they need to do something different. We
don't want to attempt to run tests that will fail unless the user has
added the right magic to their environment.

>>>>> 
>>>>> In order to overcome the above two disadvantages, we introduce a new
>>>>> environment variable IASL_PATH that can be set by the tester pointing to an
>>>>> possibly non-standard iasl binary location. Bios-tables-test then uses this
>>>>> environment variable to set its iasl location, possibly also overriding the
>>>>> location that was pointed to by CONFIG_IASL that was set by meson. This way
>>>>> developers can not only use this new environment variable to set iasl
>>>>> location to quickly run bios-tables-test but also can point the test to a
>>>>> custom iasl if required.
>>>>> 
>>>>> [1] https://mesonbuild.com/Reference-manual_functions.html#find_program
>>>>> 
>>>>> Signed-off-by: Ani Sinha <anisinha@redhat.com>
>>>> 
>>>> Well I think the point was originally that meson can
>>>> also test the binary in a variety of ways.
>>>> Never surfaced so maybe never mind.
>>>> 
>>>> Would it be easier to just look iasl up on path
>>> 
>>> But that’s what meson is also doing, only QEMU build time.
>> 
>> 
>> So you were unhappy it's build time because it is not really
>> part of build and you want flexibility, right?
>
> Hmm, maybe in that case, we might want to resurrect iasl_installed(),
> basically reverting part of cc8fa0e80836c51ba644d910c.
>
> To me its ok if I had to set IASL_PATH=`which iasl` before running the
> test. I do not have strong opinions.

I don't think so - we should be using the tools configure found, after
all that is its job.

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro