Re: [PATCH v2] util/qemu-config: Fix "query-command-line-options" to provide the right values

[Thomas Huth <thuth@redhat.com>]

On 11/11/2022 15.53, Markus Armbruster wrote:
> Thomas Huth <thuth@redhat.com> writes:
> 
>> The "query-command-line-options" command uses a hand-crafted list
>> of options that should be returned for the "machine" parameter.
>> This is pretty much out of sync with reality, for example settings
>> like "kvm_shadow_mem" or "accel" are not parameters for the machine
>> anymore. Also, there is no distinction between the targets here, so
>> e.g. the s390x-specific values like "loadparm" in this list also
>> show up with the other targets like x86_64.
>>
>> Let's fix this now by geting rid of the hand-crafted list and by
>> querying the properties of the machine classes instead to assemble
>> the list.
> 
> Do we know what uses this command, and how these users are
> inconvenienced by the flaw you're fixing?
> 
> I'm asking because the command is pretty much out of sync with reality
> by (mis-)design.

libvirt apparently queries this data (see the various 
tests/qemucapabilitiesdata/*.replies files in their repository), but since 
it's so much out-of-sync with reality, it's not of a big use there yet.

See for example here:

https://lists.gnu.org/archive/html/qemu-devel/2021-12/msg00581.html

If we finally fix this problem with "query-command-line-options" in QEMU, it 
should be much easier to deprecate -no-hpet in QEMU, too.

  Thomas