Dear Maintainer,

After upgrading our VM hosts from Debian 12 to Debian 13 (trixie),
live migration of VMs from the upgraded hosts started failing.

The affected hosts use:

  libvirt 11.3.0-3+deb13u2
  qemu-system-x86 1:11.0.2+ds-2~bpo13+1

The QEMU processes were restarted after the Debian upgrade, so all
running VMs were using the new QEMU version.

I attempted a normal live migration using virsh, for example:

  virsh -c qemu+ssh://SOURCE/system migrate \
      --live --persistent --undefinesource \
      VMNAME \
      qemu+ssh://DEST/system \
      tcp://migrate.DEST/

The migration fails with:

  error: internal error: unable to execute QEMU command 'migrate':
  Parameter 'detach' is unexpected

The problem can also be reproduced directly through QMP:

  virsh qemu-monitor-command VMNAME --pretty \
    '{"execute":"migrate","arguments":{"detach":true}}'

QEMU 11 responds with:

  Parameter 'detach' is unexpected

I locally backported the upstream libvirt change
"qemuMonitorJSONMigrate: Drop 'detach' QMP option" to
11.3.0-3+deb13u2.

After rebuilding and installing the modified libvirt package,
live migration works successfully again.

I therefore believe the Debian trixie libvirt package needs the
upstream fix for compatibility with QEMU 11.

Please consider backporting this upstream fix to the trixie package.
Alternatively, a newer libvirt version could be made available
through trixie-backports.

Upstream patch:
https://www.mail-archive.com/devel@lists.libvirt.org/msg10575.html

Running a backported version of QEMU is probably not the best idea
overall, since obviously the older libvirt cannot possibly know about
incompatible changes in the newer QEMU.

Anyway, in this case the fix is quite trivial so I've included it in
the upload that will hopefully make it into the next trixie stable
update (approval from the release team pending).

https://salsa.debian.org/libvirt-team/libvirt/-/merge_requests/296
https://bugs.debian.org/1146164

Hello,

Bug #1145836 in libvirt reported by you has been fixed in the
Git repository and is awaiting an upload. You can see the commit
message below and you can check the diff of the fix at:

https://salsa.debian.org/libvirt-team/libvirt/-/commit/706121217da9cdf77458ac4102abdfcd0f05ff19
------------------------------------------------------------------------
patches: Add backports

Specifically

  backport/qemuMonitorJSONMigrate-Drop-detach-QMP-option.patch

which fix a compatibility issue with newer versions of
QEMU (e.g. installed from trixie-backports).

Closes: #1145836
------------------------------------------------------------------------

(this message was generated automatically)
-- 
Greetings

https://bugs.debian.org/1145836

We believe that the bug you reported is fixed in the latest version of
libvirt, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1145836@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Andrea Bolognani <eof@kiyuko.org> (supplier of updated libvirt package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Sun, 30 Aug 2026 15:59:50 +0200
Source: libvirt
Architecture: source
Version: 11.3.0-3+deb13u3
Distribution: trixie
Urgency: medium
Maintainer: Debian Libvirt Maintainers <pkg-libvirt-maintainers@lists.alioth.debian.org>
Changed-By: Andrea Bolognani <eof@kiyuko.org>
Closes: 1145836
Changes:
 libvirt (11.3.0-3+deb13u3) trixie; urgency=medium
 .
   * [7061212] patches: Add backports
     - backport/qemuMonitorJSONMigrate-Drop-detach-QMP-option.patch
       - Closes: #1145836
   * [eaa378a] patches: Add backports
     - backport/remote-Fix-integer-overflow-in-RPC-handler-[...]
       - CVE-2026-18917
   * [1b35d45] patches: Add backports
     - backport/conf-reject-line-breaks-in-DNS-TXT-record-[...]
     - backport/conf-reject-line-breaks-in-DNS-SRV-domain-[...]
     - backport/network-reject-line-breaks-before-writing-[...]
     - backport/tests-cover-line-break-rejection-in-DNS-[...]
       - CVE-2026-61477
   * [4378d69] patches: Add backports
     - backport/src-fix-crash-searching-for-XML-context-string-[...]
       - CVE-2026-61478
   * [fd7eaa5] patches: Add backports
     - backport/util-virFileChownFiles-do-not-follow-symlinks.patch
       - CVE-2026-63622
   * [eccf219] patches: Add backports
     - backport/storage-create-images-with-a-private-umask-[...]
       - CVE-2026-63623
Checksums-Sha1:
 ac7af3050ddb6e719aaa906b52dc135abc4e2370 7801 libvirt_11.3.0-3+deb13u3.dsc
 483484760cf870f0f5d156a88aebb6b6c42ad242 116752 libvirt_11.3.0-3+deb13u3.debian.tar.xz
 57a1f1c594079df4d92c19aa4830835cc0aff40a 14017 libvirt_11.3.0-3+deb13u3_source.buildinfo
Checksums-Sha256:
 d6ea37b45f24dc4f484e8c8e307b8b14266804fb2c69b091a84ad2b2fac6870b 7801 libvirt_11.3.0-3+deb13u3.dsc
 ec073ef64c50ab8732d7a3887a73500d9ebcbc87b1e927d4ec69ea5c58539325 116752 libvirt_11.3.0-3+deb13u3.debian.tar.xz
 c02087dc08b099d23ee6656354e5ea85062c208b1cdb7977a741f3157bdb49b8 14017 libvirt_11.3.0-3+deb13u3_source.buildinfo
Files:
 ce51d99cfa17e8deb2c7e30a16f7d59f 7801 libs optional libvirt_11.3.0-3+deb13u3.dsc
 5048fa2a5c8cbf36bf38b6583e735da7 116752 libs optional libvirt_11.3.0-3+deb13u3.debian.tar.xz
 293a35b11e970faa0b14a86194178e2e 14017 libs optional libvirt_11.3.0-3+deb13u3_source.buildinfo
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