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[99.254.114.190]) by smtp.gmail.com with ESMTPSA id e9e14a558f8ab-3a37a808befsm20008325ab.42.2024.10.08.12.48.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Oct 2024 12:48:34 -0700 (PDT) Date: Tue, 8 Oct 2024 15:48:31 -0400 From: Peter Xu To: Fabiano Rosas Cc: Steven Sistare , qemu-devel@nongnu.org, David Hildenbrand , Marcel Apfelbaum , Eduardo Habkost , Philippe Mathieu-Daude , Paolo Bonzini , "Daniel P. Berrange" , Markus Armbruster Subject: Re: [PATCH V2 13/13] migration: cpr-transfer mode Message-ID: References: <1727725244-105198-1-git-send-email-steven.sistare@oracle.com> <1727725244-105198-14-git-send-email-steven.sistare@oracle.com> <87ed4qtpo1.fsf@suse.de> <877caitno5.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <877caitno5.fsf@suse.de> Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.151, 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, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Oct 08, 2024 at 04:11:38PM -0300, Fabiano Rosas wrote: > As of half an hour ago =) We could put a feature branch up and work > together, if you have more concrete thoughts on how this would look like > let me know. [I'll hijack this thread with one more email, as this is not cpr-relevant] I think I listed all the things I can think of in the wiki, so please go ahead. One trivial suggestion is we can start from the very simple, which is the handshake itself, with a self-bootstrap protocol, probably feature-bit based or whatever you prefer. Then we set bit 0 saying "this QEMU knows how to handshake". Comparing to the rest requirement, IMHO we can make the channel establishment the 1st feature, then it's already good for merging, having feature bit 1 saying "this qemu understands named channel establishment". Then we add new feature bits on top of the handshake feature, by adding more feature bits. Both QEMUs should first handshake on the feature bits they support and enable only the subset that all support. Or instead of bit, feature strings, etc. would all work which you prefer. Just to say we don't need to impl all the ideas there, as some of them might take more time (e.g. device tree check), and that list is probably not complete anyway. -- Peter Xu