Re: [PATCH 02/17] acpi: x86: deduplicate HPET AML building

[Igor Mammedov]

On Fri, 1 Jul 2022 12:26:16 -0400
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Fri, Jul 01, 2022 at 09:35:00AM -0400, Igor Mammedov wrote:
> > HPET AML doesn't depend on piix4 nor q35, move code buiding it
> > to common scope to avoid duplication.
> > 
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>  
> 
> Apropos, tests/data/acpi/rebuild-expected-aml.sh ignores the
> fact that some tables might be identical. Also, there's no
> way to reuse expected files between machines. And so we have:
> 
> 
> [qemu]$ find tests/data/acpi -type f -exec sha256sum '{}' ';'|sort
[...]

> 
> 
> It's easy to fix up duplications within virt. But I am not 100% sure how
> fix up duplication between q35 and pc.
[...]
 
> Then we could maybe use the directory "pc" for files common to i440fx
> and q35.  Maybe just teach the test to look under tests/data/acpi/x86
> too? And I think we should teach tests/data/acpi/rebuild-expected-aml.sh
> to check for duplicates and at least warn the user.

Probably duplicates in 'virt' mostly due to combination of not knowing
that there is a fallback lookup (which is hidden in the code)
and simplistic way tests/data/acpi/rebuild-expected-aml.sh rebuilds tables.

As you suggest, rebuild-expected-aml.sh can be improved to warn or even
better drop duplicates if found.

As for reusing tables between different machine types, alternatively
we can add explicit remapping rules (possibly auto-generated) versus
currently used implicit fallback approach.