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David Alan Gilbert" , Eric Blake , Akihiko Odaki , Paolo Bonzini , Kevin Wolf , Sana Sharma , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Juraj Marcin , qemu-rust@nongnu.org, Markus Armbruster , Mark Cave-Ayland Subject: Re: [PATCH v2 10/10] migration: Switch to TYPE_OBJECT with object properties Message-ID: References: <20260609172514.2037645-1-peterx@redhat.com> <20260609172514.2037645-11-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Jun 10, 2026 at 05:29:59PM +0100, Daniel P. Berrangé wrote: > -global is/was intended for devices, primarily those which > are created by default as part of the machine. For dynamically > created devices the docs recommend use of -device instead > of -global. I wished it was called -device-global then it'll be clearer, otherwise from an API perspective it really shouldn't be limited to qdev.. It makes sense to not call it -device-global, IMHO essentially because we don't necessarily need to restrict it to -device. > > I get that -global was exposed for migration via the inappropriate > use of TYPE_DEVICE as a parent for TYPE_MIGRATION, but I don't > think we should be prolonging that misuse by exposing use of > -global for things which are QOM rather than QDev. > > If we want todo that for the sake of backcompat, IMHO it should > be deprecated so it only lives for a short while after the > conversion to QOM. > > This makes me realize that this does not implement the UserCreatable > interface on TYPE_MIGRATION, so I'm presuming the MigrationState is > still created internally. Perhaps we should switch to making it a > full UserCreatable, such that -object can be used to set all migration > parameters on the command line and -global won't be required ? This is what Fabiano suggested in his reply here: https://lore.kernel.org/qemu-devel/87jys75npb.fsf@suse.de/ I wonder what's your view on that when put together the singleton series I used to post, where I also mentioned in the reply: https://lore.kernel.org/qemu-devel/aimtYbka4GB9Qyk6@x1.local/ If you think that's the right approach, we can try to have it to replace -global. -global is debug API for migration, we don't need to obsolete it. Compat property is, which is unaffected by this. So we can remove -global support for migration, but it'll always be good to have a replacement for scripts. Thanks, -- Peter Xu