From: Gerd Hoffmann <kraxel@redhat.com>
To: Claudio Fontana <cfontana@suse.de>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, "Eric Blake" <eblake@redhat.com>,
qemu-block@nongnu.org, "David Hildenbrand" <david@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>,
"Halil Pasic" <pasic@linux.ibm.com>,
"Christian Borntraeger" <borntraeger@de.ibm.com>,
"Samuel Thibault" <samuel.thibault@ens-lyon.org>,
"Thomas Huth" <thuth@redhat.com>,
"Michael Roth" <michael.roth@amd.com>,
"Peter Lieven" <pl@kamp.de>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
qemu-s390x@nongnu.org,
"Ronnie Sahlberg" <ronniesahlberg@gmail.com>,
"José Ricardo Ziviani" <jose.ziviani@suse.com>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Kevin Wolf" <kwolf@redhat.com>,
berrange@redhat.com, "Cornelia Huck" <cohuck@redhat.com>,
"Max Reitz" <mreitz@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [PATCH v2 00/18] modules: add metadata database
Date: Thu, 10 Jun 2021 11:54:34 +0200 [thread overview]
Message-ID: <20210610095434.iygaxizo5h3745zf@sirius.home.kraxel.org> (raw)
In-Reply-To: <dd1c5487-b1bf-9e33-fd42-fc0863e0ddd7@suse.de>
On Thu, Jun 10, 2021 at 10:32:39AM +0200, Claudio Fontana wrote:
> On 6/10/21 7:57 AM, Gerd Hoffmann wrote:
> > This patch series adds support for module metadata. Here are the pieces
> > of the puzzle:
> >
> > (1) Macros are added to store metadata in a .modinfo elf section
> > (idea stolen from the linux kernel).
> > (2) A utility to scan modules, collect metadata from the .modinfo
> > sections, store it in a file (modinfo.json) for later consumption
> > by qemu. Can also be easily inspected using 'jq'.
> > (3) Adding annotations to the modules we have.
> > (4) Drop hard-coded lists from utils/module.c
> >
> > take care,
> > Gerd
>
> The background has disappeared compared with V1.
>
> V1 says:
>
> "Background is that the hard-coded lists in util/module.c are somewhat
> ugly and also wouldn't work very well with a large number of modules,
> so I'm looking for something else."
Well, it's point (4) now (a bit short indeed ...).
> Can you write more about what the actual high level goals of this series are?
Right now we have information about modules hard-coded in various places
in qemu. Most obvious ones are module_deps[] and qom_modules[] (both in
util/module.c), but also qemu_load_module_for_opts() (in softmmu/vl.c)
and maybe more I missed.
So, when you go build some qom object modular today you'll have to go
add that to the qom_modules[] list. With this patch series applied
you'll go add a 'module_obj("typename");' to your source file instead.
Same goes for other metadata, see the "add $foo module annotations"
patches for examples.
> We are in general making QEMU more and more difficult to get into,
> requiring more and more investment for new contributors to get
> productive.
>
> Is the additional complexity justified? What is the benefit, and is
> simplification a goal of the series as well?
IMHO it is a simplification for developers. Modules are more
self-contained with this in place. You just add the annotation macros
and you are done. No need to edit manually maintained lists at some
non-obvious place elsewhere in the tree. Also no patch conflicts in
those lists. We have type_init() + friends for simliar reasons.
The price for that simplification is the new utility needed which
collects and stores the metadata. But that is something you only need
to worry about when actually working on module support. The build
system keeps the database automatically up-to-date and most developers
shouldn't even notice that it is there.
take care,
Gerd
next prev parent reply other threads:[~2021-06-10 9:56 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 5:57 [PATCH v2 00/18] modules: add metadata database Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 01/18] modules: add metadata macros, add qxl module annotations Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 02/18] qapi: add ModuleInfo schema Gerd Hoffmann
2021-06-14 7:48 ` Markus Armbruster
2021-06-14 15:21 ` Gerd Hoffmann
2021-06-14 16:53 ` Markus Armbruster
2021-06-10 5:57 ` [PATCH v2 03/18] modules: add qemu-modinfo utility Gerd Hoffmann
2021-06-10 13:04 ` Gerd Hoffmann
2021-06-10 13:13 ` Daniel P. Berrangé
2021-06-14 8:34 ` Paolo Bonzini
2021-06-14 14:36 ` Paolo Bonzini
2021-06-15 4:49 ` Gerd Hoffmann
2021-06-15 7:56 ` Gerd Hoffmann
2021-06-15 13:07 ` Gerd Hoffmann
2021-06-15 13:35 ` Paolo Bonzini
2021-06-16 9:16 ` Gerd Hoffmann
2021-06-16 10:53 ` Paolo Bonzini
2021-06-14 15:01 ` Gerd Hoffmann
2021-06-14 15:08 ` Daniel P. Berrangé
2021-06-15 4:54 ` Gerd Hoffmann
2021-06-15 9:27 ` Daniel P. Berrangé
2021-06-10 5:57 ` [PATCH v2 04/18] modules: add virtio-gpu module annotations Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 05/18] modules: add chardev " Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 06/18] modules: add audio " Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 07/18] modules: add usb-redir " Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 08/18] modules: add ccid " Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 09/18] modules: add ui " Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 10/18] modules: add s390x " Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 11/18] modules: add block " Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 12/18] modules: add module_load_path_init helper Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 13/18] modules: load modinfo.json Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 14/18] modules: use modinfo for dependencies Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 15/18] modules: use modinfo for qom load Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 16/18] modules: use modinfo for qemu opts load Gerd Hoffmann
2021-06-10 5:57 ` [PATCH v2 17/18] modules: check arch and block load on mismatch Gerd Hoffmann
2021-06-10 12:35 ` Daniel P. Berrangé
2021-06-10 12:57 ` Gerd Hoffmann
2021-06-10 13:06 ` Daniel P. Berrangé
2021-06-10 14:03 ` Gerd Hoffmann
2021-06-14 11:23 ` Claudio Fontana
2021-06-14 13:44 ` Gerd Hoffmann
2021-06-14 13:52 ` Daniel P. Berrangé
2021-06-14 14:10 ` Gerd Hoffmann
2021-06-14 11:19 ` Claudio Fontana
2021-06-10 5:57 ` [PATCH v2 18/18] [fixup] module_load_modinfo Gerd Hoffmann
2021-06-10 6:24 ` Gerd Hoffmann
2021-06-10 8:32 ` [PATCH v2 00/18] modules: add metadata database Claudio Fontana
2021-06-10 9:54 ` Gerd Hoffmann [this message]
2021-06-14 11:31 ` Claudio Fontana
2021-06-14 14:07 ` Gerd Hoffmann
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