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[188.85.150.151]) by smtp.gmail.com with ESMTPSA id r16-20020a056000015000b0031aef72a021sm1880617wrx.86.2023.10.18.04.24.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Oct 2023 04:24:06 -0700 (PDT) From: Juan Quintela To: Peter Maydell Cc: qemu-devel@nongnu.org, Peter Xu , Leonardo Bras , Fabiano Rosas , Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH v2 1/3] migration/doc: Add documentation for backwards compatiblity In-Reply-To: (Peter Maydell's message of "Tue, 17 Oct 2023 17:20:01 +0100") References: <20231017151857.21328-1-quintela@redhat.com> <20231017151857.21328-2-quintela@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.3 (gnu/linux) Date: Wed, 18 Oct 2023 13:24:06 +0200 Message-ID: <87il74kwbt.fsf@secure.mitica> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=170.10.129.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Peter Maydell wrote: > On Tue, 17 Oct 2023 at 16:20, Juan Quintela wrote: >> >> State what are the requeriments to get migration working between qemu >> versions. And once there explain how one is supposed to implement a >> new feature/default value and not break migration. >> >> Reviewed-by: Vladimir Sementsov-Ogievskiy >> Acked-by: Peter Xu >> Signed-off-by: Juan Quintela >> --- >> docs/devel/migration.rst | 217 +++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 217 insertions(+) >> >> diff --git a/docs/devel/migration.rst b/docs/devel/migration.rst >> index c3e1400c0c..5ef2b36e9e 100644 >> --- a/docs/devel/migration.rst >> +++ b/docs/devel/migration.rst >> @@ -142,6 +142,223 @@ General advice for device developers >> may be different on the destination. This can result in the >> device state being loaded into the wrong device. >> >> +How backwards compatibility works >> +--------------------------------- > > Is there a better place in this document that we could add > this information? > At the moment these new sections have > been placed in the middle of the "Saving the state of one device" > section, which doesn't seem right; worse, it's between the > "General advice for device developers" and the "VMState" > subsections of that section, which means that we end up with > a very long part of the document that is talking about edge > cases, and which splits up the two parts of the document that > are really all most device model authors need to think about. You are right. I didn't know for a good place either. I created a new section: Backwards compatibility At the end of the archive. > My guess is that the extra documentation on backwards > compatibility that these patches are adding should get > a new section of its own (at the same level as the current > top-level sections "Transports", "Debugging", etc) which > then has its own subsections; and that this should probably > go either at the bottom of the document, after "Firmware", > or else just before "Stream structure". End it is. > We should probably also add a > .. contents:: > directive near the start of the page, since it's now big > enough and has enough sections and subsections that a > table of contents would be helpful. Also done. Thanks a lot.