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Tsirkin" To: Peter Xu Cc: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Thomas Huth , Yuri Benditovich , eduardo@habkost.net, marcel.apfelbaum@gmail.com, philmd@linaro.org, wangyanan55@huawei.com, dmitry.fleytman@gmail.com, akihiko.odaki@daynix.com, jasowang@redhat.com, sriram.yagnaraman@est.tech, sw@weilnetz.de, qemu-devel@nongnu.org, yan@daynix.com, Fabiano Rosas , devel@lists.libvirt.org Subject: Re: [PATCH v2 4/4] virtio-net: Add support for USO features Message-ID: <20240801113826-mutt-send-email-mst@kernel.org> References: <20240730151746-mutt-send-email-mst@kernel.org> <20240730172148-mutt-send-email-mst@kernel.org> <20240731033803-mutt-send-email-mst@kernel.org> <20240801014222-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@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=-0.131, 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, 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 Thu, Aug 01, 2024 at 11:36:19AM -0400, Peter Xu wrote: > On Thu, Aug 01, 2024 at 01:51:00AM -0400, Michael S. Tsirkin wrote: > > So I suggest a single command that dumps some description of host > > features, to be passed to qemu on destination. qemu then fails to > > start on destination if some of these do not work. > > The advantage is that this also helps things like -cpu host, > > and a bunch of other things like vdpa where we like to pass through > > config from kernel. > > Something like that could work indeed. I'm thinking whether it shouldn't > require a new QMP command; that sounds more work, and we also needs Libvirt > cooperations so QEMU migration will still fail. I wonder whether we can > integrate it into migration handshake that I referred previously in our > TODO item here: > > https://wiki.qemu.org/ToDo/LiveMigration#Migration_handshake This is different. You can start migration on destination without touching source at all. This allows e.g. finding a destination that can support your source.