[pve-devel] [PATCH qemu-server/docs v4 00/16] adapt to changes in QEMU machine version deprecation/removal

[Fiona Ebner]

Changes in v4:
* dropped already applied patch
* move import for get_host_arch() to earlier patch where it is already needed
* squash rename and move patches for get_command_for_arch() together
* rename machine_version_at_least -> is_machine_version_at_least
* use a dedicated section to describe the new removal policy
* drop table, instead describe how the cut-off decision is made with examples

Changes in v3:
* improve code readibility for Windows machine version fallback change

Changes in v2:
* change deprecation logic into QEMU itself rather than just weakening
  the warning there (so no need to change the deprecation logic in
  qemu-server anymore)
* get rid of outdated information from "Update to a Newer Machine
  Version" section in docs

In QEMU commit a35f8577a0 ("include/hw: add macros for deprecation &
removal of versioned machines"), a new machine version deprecation and
removal policy was introduced. After only 3 years a machine version
will be deprecated while being removed after 6 years.

The deprecation is a bit early considering major PVE releases are
approximately every 2 years. This means that a deprecation warning can
already happen for a machine version that was introduced during the
previous major release. This would scare users for no good reason, so
avoid deprecating machine versions in PVE too early and define a
baseline of machine versions that will be supported throughout a
single major PVE release.

The new policy takes effect only in QEMU 10.1, see QEMU commit
c9fd2d9a48 ("include/hw: temporarily disable deletion of versioned
machine types"). Machine versions <=2.3 were already deprecated for a
while, with PVE also warning about it since commit dec371d9 ("vm
start: add warning about deprecated machine version") in qemu-server
8.0.8. These have been dropped in QEMU 9.1, so the baseline for PVE 8
is 2.4.

This series is intended to allow broader QEMU 9.1 rollout. Still
required in addition to this series before PVE 9:
* wiki article about what to look out for when changing machine
  version
* checks in pve8to9 script giving errors/warnings when machine version
  is too old

qemu-server:

Fiona Ebner (15):
  machine: drop unused parameter from assert_valid_machine_property()
    helper
  move get_command_for_arch() helper to helpers module
  move kvm_user_version() function to helpers module
  move get_vm_arch() helper to helpers module
  machine: add default_machine_for_arch() helper
  move get_installed_machine_version() helper to machine module
  move windows_get_pinned_machine_version() function to machine module
  move get_vm_machine() function to machine module
  move meta information handling to its own module
  machine: fallback to creation QEMU version for windows starting with
    9.1
  machine: add check_and_pin_machine_string() helper
  api: update vm config: pin machine version when switching to windows
    os type
  machine: log informational line when pinning machine version for
    Windows guest
  machine: rename machine_version() function to
    is_machine_version_at_least()
  machine: code cleanup: avoid superfluous augmented assignment operator

 PVE/API2/Qemu.pm                 |  44 +++++---
 PVE/QemuServer.pm                | 184 +++----------------------------
 PVE/QemuServer/Helpers.pm        |  49 ++++++++
 PVE/QemuServer/Machine.pm        | 108 +++++++++++++++++-
 PVE/QemuServer/Makefile          |   1 +
 PVE/QemuServer/MetaInfo.pm       |  47 ++++++++
 test/run_config2command_tests.pl |   3 +-
 7 files changed, 249 insertions(+), 187 deletions(-)
 create mode 100644 PVE/QemuServer/MetaInfo.pm


pve-docs:

Fiona Ebner (1):
  qm: machine version: document support in PVE

 qm.adoc | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)


Summary over all repositories:
  8 files changed, 275 insertions(+), 195 deletions(-)

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