From 5b4f68560624dae0342e55816f51dc6b47b5a2a3 Mon Sep 17 00:00:00 2001 From: Fiona Ebner Date: Fri, 17 Jan 2025 15:24:30 +0100 Subject: [PATCH] qm: machine version: document support in PVE Elaborate on new QEMU machine version removal policy and how PVE will support machine versions. Signed-off-by: Fiona Ebner --- qm.adoc | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/qm.adoc b/qm.adoc index 94fdd4e..4bb8f2c 100644 --- a/qm.adoc +++ b/qm.adoc @@ -173,19 +173,37 @@ This means that after a fresh start, the newest machine version supported by the QEMU binary is used (e.g. the newest machine version QEMU 8.1 supports is version 8.1 for each machine type). +QEMU Machine Version Deprecation +++++++++++++++++++++++++++++++++ + +Starting with QEMU 10.1, machine versions are removed from upstream QEMU after 6 +years. In {pve}, major releases happen approximately every 2 years, so a major +{pve} release will support machine versions from approximately two previous +major {pve} releases. + +Before upgrading to a new major {pve} release, you should update VM +configurations to avoid all machine versions that will be dropped during the +next major {pve} release. This ensures that the guests can still be used +throughout that release. See the section +xref:qm_machine_update[Update to a Newer Machine Version]. + +The removal policy is not yet in effect for {pve} 8, so the baseline for +supported machine versions is 2.4. The last QEMU binary version released for +{pve} 9 is expected to be QEMU 11.2. This QEMU binary will remove support for +machine versions older than 6.0, so 6.0 is the baseline for the {pve} 9 release +life cycle. The baseline is expected to increase by 2 major versions for each +major {pve} release, for example 8.0 for {pve} 10. + [[qm_machine_update]] Update to a Newer Machine Version +++++++++++++++++++++++++++++++++ -Very old machine versions might become deprecated in QEMU. For example, this is -the case for versions 1.4 to 1.7 for the i440fx machine type. It is expected -that support for these machine versions will be dropped at some point. If you -see a deprecation warning, you should change the machine version to a newer one. -Be sure to have a working backup first and be prepared for changes to how the -guest sees hardware. In some scenarios, re-installing certain drivers might be -required. You should also check for snapshots with RAM that were taken with -these machine versions (i.e. the `runningmachine` configuration entry). +If you see a deprecation warning, you should change the machine version to a +newer one. Be sure to have a working backup first and be prepared for changes to +how the guest sees hardware. In some scenarios, re-installing certain drivers +might be required. You should also check for snapshots with RAM that were taken +with these machine versions (i.e. the `runningmachine` configuration entry). Unfortunately, there is no way to change the machine version of a snapshot, so you'd need to load the snapshot to salvage any data from it.