Re: [PATCH qemu-server v2] fix #5578: smbios: set serial number

[Manuel Federanko <m.federanko@proxmox.com>]

On 2026-02-19 3:55 PM, Fiona Ebner wrote:
> Am 19.02.26 um 12:19 PM schrieb Manuel Federanko:
>> If no smbios options are given on creation, default to generate a serial
>> number. This is required for Windows Autopilot to identify a user
>> device.
>> Use the already generated smbios uuid as serial number, it should be
>> unique enough for our purposes.
> 
> The bug report mentions VMWare using "VMware-42 xx yy zz .....". Maybe
> we should also use a "Proxmox-" prefix or similar?

Agreed, I'm open to suggestions on what exactly the prefix should be,
"Proxmox-" sounds good though, maybe "PMX-" or "PVE-" as suggested by
Stoiko off-list.

> I do wonder if we should set this unconditionally or somehow guard it,
> e.g. only do it for win11 OS type, or if guarding would be overly
> cautious. It does only affect new VMs, so if this does cause some kind
> of regression, we can still adapt it again.
> 
>> The base64 here is needed since all configuration options are stored as
>> a base64 encoded string, which is ensured by the format. This ensures
>> that the values are properly decoded in the gui, for example.
>> 
>> Since all fields are forced to be stored in base64 format it might make
>> sense for a future patch to a) remove the flag or b) allow values
>> different than base64 encoded data in the other fields.
> 
> Note that absence of the flag is needed for backwards compatibility with
> pre-existing configuration files (also in backups) from before the flag
> was introduced [0]. If the base64=1 is not set, the values are
> interpreted directly and not decoded first.
> 
>> Tested by creating a new vm via the gui and command line.
>> 
>> Signed-off-by: Manuel Federanko <m.federanko@proxmox.com>
>> ---
>> Changes since v1:
>> * switch serial to be the same uuid
>> * use print_smbios1 over manually constructing strings
>> * remove the dedicated generate_smbios1_uuid subroutine
>> 
>>  src/PVE/API2/Qemu.pm  |  9 ++++++++-
>>  src/PVE/CLI/qm.pm     | 10 +++++++++-
>>  src/PVE/QemuServer.pm |  4 ----
>>  3 files changed, 17 insertions(+), 6 deletions(-)
>> 
>> diff --git a/src/PVE/API2/Qemu.pm b/src/PVE/API2/Qemu.pm
>> index c2e185a6..bbf534e4 100644
>> --- a/src/PVE/API2/Qemu.pm
>> +++ b/src/PVE/API2/Qemu.pm
> 
> Missing use statement for MIME::Base64
> 
>> @@ -1471,7 +1471,14 @@ __PACKAGE__->register_method({
>>  
>>                      # auto generate uuid if user did not specify smbios1 option
>>                      if (!$conf->{smbios1}) {
>> -                        $conf->{smbios1} = PVE::QemuServer::generate_smbios1_uuid();
>> +                        my $smbios1_uuid = PVE::QemuServer::generate_uuid();
>> +                        my $smbios1_serial = MIME::Base64::encode_base64($smbios1_uuid, "");
>> +                        my %smbios1 = (
> 
> Style nit: our code base mostly uses hash references rather than hashes
> directly. Especially, since you need to pass it along as a reference,
> you can already define it as such.
> 
>> +                            uuid => $smbios1_uuid,
>> +                            serial => $smbios1_serial,
>> +                            base64 => 1,
>> +                        );
>> +                        $conf->{smbios1} = PVE::QemuServer::print_smbios1(\%smbios1);
>>                      }
>>  
>>                      if (
>> diff --git a/src/PVE/CLI/qm.pm b/src/PVE/CLI/qm.pm
>> index bdae9641..0daf402d 100755
>> --- a/src/PVE/CLI/qm.pm
>> +++ b/src/PVE/CLI/qm.pm
> 
> Missing use statement for MIME::Base64
> 
>> @@ -912,7 +912,15 @@ __PACKAGE__->register_method({
>>          eval {
>>              # order matters, as do_import() will load_config() internally
>>              $conf->{vmgenid} = PVE::QemuServer::generate_uuid();
>> -            $conf->{smbios1} = PVE::QemuServer::generate_smbios1_uuid();
>> +            my $smbios1_uuid = PVE::QemuServer::generate_uuid();
>> +            my $smbios1_serial = MIME::Base64::encode_base64($smbios1_uuid, "");
>> +            my %smbios1 = (
>> +                uuid => $smbios1_uuid,
>> +                serial => $smbios1_serial,
>> +                base64 => 1,
>> +            );
>> +            $conf->{smbios1} = PVE::QemuServer::print_smbios1(\%smbios1);
>> +
>>              PVE::QemuConfig->write_config($vmid, $conf);
>>  
>>              foreach my $disk (@{ $parsed->{disks} }) {
>> diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
>> index 545758dc..b371d00b 100644
>> --- a/src/PVE/QemuServer.pm
>> +++ b/src/PVE/QemuServer.pm
>> @@ -8082,10 +8082,6 @@ sub generate_uuid {
>>      return $uuid_str;
>>  }
>>  
>> -sub generate_smbios1_uuid {
>> -    return "uuid=" . generate_uuid();
> 
> Rather than removing the helper here, it could be extended. This would
> avoid duplicating the behavior on the (previous) call sites that need it.

Will extend the helper, which makes the use statements moot, and switch to
a hash reference.

>> -}
>> -
>>  sub create_reboot_request {
>>      my ($vmid) = @_;
>>      open(my $fh, '>', "/run/qemu-server/$vmid.reboot")
> 
> [0]:
> https://git.proxmox.com/?p=qemu-server.git;a=commitdiff;h=1f30ac3a9f18c215d3e3c657f9e81d9d3125f46c