[pve-devel] [PATCH qemu-server v3 12/18] machine: fallback to creation QEMU version for windows starting with 9.1

[Fiona Ebner]

Starting from QEMU creation version 9.1, pin to the creation version
instead. Support for machine version 5.1 is expected to drop with QEMU
11.1 and it would still be good to handle Windows VMs that do not have
explicit machine version for whatever reason. For example, explicitly
setting the machine without a version on the CLI/API after creation is
one way to end up with such a machine.

Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---
 PVE/QemuServer/Machine.pm | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/PVE/QemuServer/Machine.pm b/PVE/QemuServer/Machine.pm
index 915913c0..40100555 100644
--- a/PVE/QemuServer/Machine.pm
+++ b/PVE/QemuServer/Machine.pm
@@ -4,6 +4,7 @@ use strict;
 use warnings;
 
 use PVE::QemuServer::Helpers;
+use PVE::QemuServer::MetaInfo;
 use PVE::QemuServer::Monitor;
 use PVE::JSONSchema qw(get_standard_option parse_property_string print_property_string);
 
@@ -221,11 +222,24 @@ sub get_vm_machine {
 
     if (!$machine || $machine =~ m/^(?:pc|q35|virt)$/) {
 	my $kvmversion //= PVE::QemuServer::Helpers::kvm_user_version();
-	# we must pin Windows VMs without a specific version to 5.1, as 5.2 fixed a bug in ACPI
-	# layout which confuses windows quite a bit and may result in various regressions..
+	# we must pin Windows VMs without a specific version and no meta info about creation QEMU to
+	# 5.1, as 5.2 fixed a bug in ACPI layout which confuses windows quite a bit and may result
+	# in various regressions..
 	# see: https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg08484.html
+	# Starting from QEMU 9.1, pin to the creation version instead. Support for 5.1 is expected
+	# to drop with QEMU 11.1 and it would still be good to handle Windows VMs that do not have
+	# an explicit machine version for whatever reason.
 	if (PVE::QemuServer::Helpers::windows_version($conf->{ostype})) {
-	    $machine = windows_get_pinned_machine_version($machine, '5.1', $kvmversion);
+	    my $base_version = '5.1';
+	    # TODO PVE 10 - die early if there is a Windows VM both without explicit machine version
+	    # and without meta info.
+	    if (my $meta = PVE::QemuServer::MetaInfo::parse_meta_info($conf->{meta})) {
+		if (PVE::QemuServer::Helpers::min_version($meta->{'creation-qemu'}, 9, 1)) {
+		    # need only major.minor
+		    ($base_version) = ($meta->{'creation-qemu'} =~ m/^(\d+.\d+)/);
+		}
+	    }
+	    $machine = windows_get_pinned_machine_version($machine, $base_version, $kvmversion);
 	}
 	$arch //= 'x86_64';
 	$machine ||= default_machine_for_arch($arch);
-- 
2.39.5