Re: [PATCH v4 0/6] single-binary: deduplicate target_info()

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, May 05, 2026 at 03:48:20PM -0700, Pierrick Bouvier wrote:
> We are getting close to be able to link several targets in a single QEMU system
> binary, and the last obstacle on the road is to embed several TargetInfo in the
> same binary. The end result of this series is to have a single definition for
> target_info symbol.
> 
> This series adds TargetInfo types in QOM, and retrieve them dynamically(). At
> the moment, we don't deal yet with multiple TargetInfo selection, but install
> all that is needed to be able to do it easily.
> 
> Because TargetInfo data is set through class_init, it creates an issue at
> startup, where we may try to instantiate additional (unrelated) types just to
> retrieve the list of "target-info-X" types. Those other types class_init may be
> using target information, to add target specific properties for instance.
> This issue has been fixed by adding a new object_class_get_list_by_name_prefix
> that does not force instantiation of all QOM types, but only those matching a
> specific pattern. This way, we first initialize and retrieve target-info types
> before others.
> 
> An alternative would be to leave all this out of QOM, and use startup
> initializer to add them in a single list. However, because all the single-binary
> work has been using QOM where possible, it would be really sad to not use it for
> this final step. Comments are welcome!
> 
> Finally, sticking to our promise not create a special "single-binary
> configuration", the goal is to use the *exact* same codepath for normal binaries
> also. It means that even for existing system binaries, the goal will be to use
> QOM to retrieve current target, even if there is only one.
> 
> v4
> --
> 
> - Revert to v2 MODULE_INIT_TARGET_INFO as Daniel didn't comment on issues about
>   about MODULE_INIT_QOM_EARLY.

Sorry for  not responding to that, other things got in the way
this week.

For clarity, I withdraw my objections from v2. Having seen how
my suggested approadch in v3 looked, I think you were correct
all along.

With regards,
Daniel
-- 
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