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2022-01-27docs/qapi-code-gen: update to cover trace events code generationVladimir Sementsov-Ogievskiy
Previous commits enabled trace events generation for most of QAPI generated code (except for tests/ and qga/). Let's update documentation to illustrate it. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20220126161130.3240892-6-vsementsov@virtuozzo.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2022-01-27qapi/commands: refactor error handling codeVladimir Sementsov-Ogievskiy
Move error_propagate() to if (err) and make "if (err)" block mandatory. This is to simplify further commit, which will bring trace events generation for QMP commands. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20220126161130.3240892-3-vsementsov@virtuozzo.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2021-11-10docs/devel/qapi-code-gen: Belatedly document feature documentationMarkus Armbruster
Commit 6a8c0b5102 "qapi: Add feature flags to struct types" neglected to document how to document feature flags. Make up for that. Cc: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20211026111023.76937-3-armbru@redhat.com> [Editing accident fixed]
2021-11-10docs/devel/qapi-code-gen: Drop a duplicate paragraphMarkus Armbruster
Commit 55ec69f8b1 "docs/devel/qapi-code-gen.txt: Update to new rST backend conventions" accidentally duplicated a paragraph. Drop it. Cc: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20211026111023.76937-2-armbru@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
2021-10-29qapi: New special feature flag "unstable"Markus Armbruster
By convention, names starting with "x-" are experimental. The parts of external interfaces so named may be withdrawn or changed incompatibly in future releases. The naming convention makes unstable interfaces easy to recognize. Promoting something from experimental to stable involves a name change. Client code needs to be updated. Occasionally bothersome. Worse, the convention is not universally observed: * QOM type "input-barrier" has properties "x-origin", "y-origin". Looks accidental, but it's ABI since 4.2. * QOM types "memory-backend-file", "memory-backend-memfd", "memory-backend-ram", and "memory-backend-epc" have a property "x-use-canonical-path-for-ramblock-id" that is documented to be stable despite its name. We could document these exceptions, but documentation helps only humans. We want to recognize "unstable" in code, like "deprecated". So support recognizing it the same way: introduce new special feature flag "unstable". It will be treated specially by the QAPI generator, like the existing feature flag "deprecated", and unlike regular feature flags. This commit updates documentation and prepares tests. The next commit updates the QAPI schema. The remaining patches update the QAPI generator and wire up -compat policy checking. Management applications can then use query-qmp-schema and -compat to manage or guard against use of unstable interfaces the same way as for deprecated interfaces. docs/devel/qapi-code-gen.txt no longer mandates the naming convention. Using it anyway might help writers of programs that aren't full-fledged management applications. Not using it can save us bothersome renames. We'll see how that shakes out. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Message-Id: <20211028102520.747396-2-armbru@redhat.com>
2021-10-27qapi: Add feature flags to enum membersMarkus Armbruster
This is quite similar to commit 84ab008687 "qapi: Add feature flags to struct members", only for enums instead of structs. Special feature flag 'deprecated' is silently ignored there. This is okay only because it will be implemented shortly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20211025042405.3762351-3-armbru@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
2021-10-27qapi: Enable enum member introspection to show more than nameMarkus Armbruster
The next commit will add feature flags to enum members. There's a problem, though: query-qmp-schema shows an enum type's members as an array of member names (SchemaInfoEnum member @values). If it showed an array of objects with a name member, we could simply add more members to these objects. Since it's just strings, we can't. I can see three ways to correct this design mistake: 1. Do it the way we should have done it, plus compatibility goo. We want a ['SchemaInfoEnumMember'] member in SchemaInfoEnum. Since changing @values would be a compatibility break, add a new member @members instead. @values is now redundant. In my testing, output of qemu-system-x86_64's query-qmp-schema grows by 11% (18.5KiB). We can deprecate @values now and drop it later. This will break outmoded clients. Well-behaved clients such as libvirt are expected to break cleanly. 2. Like 1, but omit "boring" elements of @member, and empty @member. @values does not become redundant. @members augments it. Somewhat cumbersome, but output of query-qmp-schema grows only as we make enum members non-boring. There is nothing to deprecate here. 3. Versioned query-qmp-schema. query-qmp-schema provides either @values or @members. The QMP client can select which version it wants. There is no redundant output. We can deprecate old versions and eventually drop them. This will break outmoded clients. Breaking cleanly is easier than for 1. While 1 and 2 operate within the common rules for compatible evolution apply (section "Compatibility considerations" in docs/devel/qapi-code-gen.rst), 3 bypasses them. Attractive when operating within the rules is just too awkward. Not the case here. This commit implements 1. Libvirt developers prefer it. Deprecate @values in favour of @members. Since query-qmp-schema compatibility is pretty fundamental for management applications, an extended grace period is advised. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Peter Krempa <pkrempa@redhat.com> Acked-by: Peter Krempa <pkrempa@redhat.com> Message-Id: <20211025042405.3762351-2-armbru@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com>
2021-09-27qapi: Drop simple unionsMarkus Armbruster
Simple unions predate flat unions. Having both complicates the QAPI schema language and the QAPI generator. We haven't been using simple unions in new code for a long time, because they are less flexible and somewhat awkward on the wire. The previous commits eliminated simple union from the tree. Now drop them from the QAPI schema language entirely, and update mentions of "flat union" to just "union". Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20210917143134.412106-22-armbru@redhat.com>
2021-09-25qapi: Tidy up unusual line breaksMarkus Armbruster
Break lines between members instead of within members. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20210917143134.412106-2-armbru@redhat.com>
2021-08-26docs: update the documentation upfront about schema configurationMarc-André Lureau
Update the documentation describing the changes in this series. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Tested-by: John Snow <jsnow@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20210804083105.97531-2-marcandre.lureau@redhat.com> [Rebased with straightforward conflicts] Signed-off-by: Markus Armbruster <armbru@redhat.com>
2021-08-04docs/qapi-code-gen: add cross-referencesJohn Snow
Add clickables to many places. Signed-off-by: John Snow <jsnow@redhat.com> Message-Id: <20210720235619.2048797-4-jsnow@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2021-08-04docs/qapi-code-gen: Beautify formattingJohn Snow
Mostly, add ``literal`` markers to a lot of things like C types, add code blocks, and fix the way a few things render. Signed-off-by: John Snow <jsnow@redhat.com> Message-Id: <20210720235619.2048797-3-jsnow@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2021-08-04docs: convert qapi-code-gen.txt to ReSTJohn Snow
This is a very rudimentary conversion from .txt to .rst changing as little as possible, but getting it to render somewhat nicely; without using any Sphinx directives. (It is 'native' ReST.) Further patches will add cross-references and Sphinx-specific extensions to make it sparkle. Signed-off-by: John Snow <jsnow@redhat.com> Message-Id: <20210720235619.2048797-2-jsnow@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Markus Armbruster <armbru@redhat.com>