[pve-devel] [PATCH 3/3] kvm: introduce qemuver and set machine flag based on qemuver

[Stefan Priebe]

Am 28.05.2013 06:19, schrieb Dietmar Maurer:
>> Signed-off-by: Stefan Priebe <s.priebe at profihost.ag>
>> ---
>>   PVE/QemuServer.pm |   35 ++++++++++++++++++++++++++++++++++-
>>   1 file changed, 34 insertions(+), 1 deletion(-)
>>
>> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm index
>> 2dba4ec..8e633bb 100644
>> --- a/PVE/QemuServer.pm
>> +++ b/PVE/QemuServer.pm
>> @@ -242,6 +242,11 @@ my $confdesc = {
>>   	description => "qemu machine version",
>>   	enum => [qw(pc q35 pc-q35-1.6 pc-q35-1.5 pc-q35-1.4 pc-i440fx-1.6
>> pc-i440fx-1.5 pc-i440fx-1.4)],
>
>
> We will end up with an endless list here?
>
> q35 pc-q35-1.6 q35 pc-q35-1.7 q35 pc-q35-1.8 q35 pc-q35-1.9 .....
>
>>       },
>> +    qemuver => {
>> +	optional => 1,
>> +	type => 'string',
>> +	description => "last qemu version when vm was started",
>> +    },
>>       description => {
>>   	optional => 1,
>>   	type => 'string',
>> @@ -688,6 +693,26 @@ sub version_to_int {
>>       die "Cannot read version $ver\n";
>>   }
>>
>> +my @qemuver_to_machine = (
>> +    { ver => version_to_int('1.4'), machine => 'pc-i440fx-1.4' },
>> +    { ver => version_to_int('1.5'), machine => 'pc-i440fx-1.5' },
>> +    { ver => version_to_int('1.6'), machine => 'pc-i440fx-1.6' }, );
>> +
>> +sub get_kvm_machine_by_qemuver {
>> +    my $qemuver = shift;
>> +
>> +    # we have no qemu version at all this might happen on VMs never started
>> since introducing qemuver
>> +    return $qemuver_to_machine[0]->{machine} if !$qemuver;
>> +
>> +    # this is an ordered array to the first reversed match is fine
>> +    foreach my $qm (reverse @qemuver_to_machine) {
>> +       return $qm->{machine} if ($qm->{ver} <= version_to_int($qemuver));
>> +    }
>> +
>> +    die "unsupported qemu version: $qemuver\n"; }
>> +
>>   my $kernel_has_vhost_net = -c '/dev/vhost-net';
>>
>>   sub disknames {
>> @@ -2390,7 +2415,9 @@ sub config_to_command {
>>
>>       push @$rtcFlags, 'driftfix=slew' if $tdf;
>>
>> -    push @$machineFlags, $conf->{machine} if $conf->{machine};
>> +    my $machine = $conf->{machine} //
>> get_kvm_machine_by_qemuver($conf->{qemuver});
>> +    push @$machineFlags, $machine;
>> +
>>       if ($nokvm) {
>>   	push @$machineFlags, 'accel=tcg';
>>       } else {
>> @@ -2997,6 +3024,12 @@ sub vm_start {
>>   	# set environment variable useful inside network script
>>   	$ENV{PVE_MIGRATED_FROM} = $migratedfrom if $migratedfrom;
>>
>> +        # always safe qemu version in config file - if we have a fresh start
>> +        if (!$statefile && !$migratedfrom) {
>> +            $conf->{qemuver} = kvm_user_version();
>> +            update_config_nolock($vmid, $conf, 1);
>> +        }
>> +
>
> IMHO vm_start should not touch/modify the configuration file.
> I guess we just need to save the machine for snapshots.

But the qemu version might have change since you started the VM. So if 
you query the version on doing the snapshot it might not be the version 
actually running. This also affects migrations.

Stefan