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Fri, 27 Feb 2026 04:59:36 -0500 (EST) Date: Fri, 27 Feb 2026 10:59:35 +0100 From: Klaus Jensen To: Alexander Mikhalitsyn Cc: qemu-devel@nongnu.org, Jesper Devantier , Peter Xu , Fabiano Rosas , qemu-block@nongnu.org, Keith Busch , Alexander Mikhalitsyn Subject: Re: [PATCH 0/4] [RFC] hw/nvme: add basic live migration support Message-ID: References: <20260217152517.271422-1-alexander@mihalicyn.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="drv9vBNIkbi6+QSk" Content-Disposition: inline In-Reply-To: <20260217152517.271422-1-alexander@mihalicyn.com> Received-SPF: pass client-ip=103.168.172.150; envelope-from=its@irrelevant.dk; helo=fout-a7-smtp.messagingengine.com X-Spam_score_int: -17 X-Spam_score: -1.8 X-Spam_bar: - X-Spam_report: (-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.306, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.668, SPF_HELO_PASS=-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: 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 --drv9vBNIkbi6+QSk Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Feb 17 16:25, Alexander Mikhalitsyn wrote: > From: Alexander Mikhalitsyn >=20 > Dear friends, >=20 > This patchset adds basic live migration support for > QEMU emulated NVMe device. >=20 > Implementation has some limitations: > - only one NVMe namespace is supported > - SMART counters are not preserved > - CMB is not supported > - PMR is not supported > - SPDM is not supported > - SR-IOV is not supported > - AERs are not fully supported >=20 > I believe this is something I can support in next patchset versions or > separately on-demand (when usecase appears). But I wanted to share this > first version as RFC to get some feedback on this in case if I'm approach= ing > it wrong. >=20 Hi Alex, Nice work! As you have already identified, there are a lot of features that are non-trivial to implement migration for. I am completely in favor of only supporting migration on a very limited feature set (i.e., don't worry about CMB, PMR, SPDM, SR-IOV, ZNS/FDP and so on). Focus on the bare mandatory requirements. It would be preferable if the "is migration possible?" test is an allowlist instead of a denylist. That makes sure we don't add a feature down the road and forget to add it to the denylist. I'm not 100% sure how to go about that at this point. AERs are something we need to deal with. We should not drop events. I don't think I have a problem with aborting enqueued AERs, but not the events. Finally, this at a minimum needs somekind of simple smoke test to catch regressions. Preferably as part of the QEMU test suite itself, but if that is hard to achieve, then I may be ok with an out-of-tree test that maintainers can use. Cheers, Klaus --drv9vBNIkbi6+QSk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEUigzqnXi3OaiR2bATeGvMW1PDekFAmmhawQACgkQTeGvMW1P DelzBQf+JU4qtXatKaO9/Fp2UzwNUfkKnX++tINzMtMcOJjjHvTF39GP4khEJ42y AbUldIEXCPTkS998Bg6eyDEjjevmjWPwfasEP8kGRjv+BU/m7wzQb/8gvJm9aONQ y2SuDs+oFBsOX2SwEuip+7bqbMyQtYSGp0jLr1dhEDfZs3LLqRrG2tLtkDkJVffZ AjtDievovllx60DIMULmKXilfn+Emw4eRYh61r6qHANFddkJRx4by7C3M3JRRfaw TQvI3voGIra9UenVdSA9F+ss+ofuatu/ZOU+RPmXvACkjBwfoR3Mg1bMekXgAV9c 4O5biVbIkapZ7L2QXX0p7uc9QwrjWQ== =2TOr -----END PGP SIGNATURE----- --drv9vBNIkbi6+QSk--