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

[Stoiko Ivanov <s.ivanov@proxmox.com>]

Thanks for tackling this!

comments/questions inline:

On Wed, 18 Feb 2026 15:29:35 +0100
Manuel Federanko <m.federanko@proxmox.com> wrote:

> 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.
The commit message could include a few more details - explaining some
choices - e.g. - the bugzilla request suggest to use a (substring of) the
smbios UUID (which should be unique and thus maybe a ok choice for a
machine-serial number) as serial number - why did you chose to generate
another random string? (if possible re-using parts of the uuid would sound
elegant to me)


> 
> Signed-off-by: Manuel Federanko <m.federanko@proxmox.com>
> ---
>  src/PVE/API2/Qemu.pm  | 5 ++++-
>  src/PVE/CLI/qm.pm     | 5 ++++-
>  src/PVE/QemuServer.pm | 6 ++++++
>  3 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/src/PVE/API2/Qemu.pm b/src/PVE/API2/Qemu.pm
> index c2e185a6..8d1e3ec0 100644
> --- a/src/PVE/API2/Qemu.pm
> +++ b/src/PVE/API2/Qemu.pm
> @@ -1471,7 +1471,10 @@ __PACKAGE__->register_method({
>  
>                      # auto generate uuid if user did not specify smbios1 option
>                      if (!$conf->{smbios1}) {
> -                        $conf->{smbios1} = PVE::QemuServer::generate_smbios1_uuid();
> +                        $conf->{smbios1} =
> +                            PVE::QemuServer::generate_smbios1_uuid() . ","
> +                            . PVE::QemuServer::generate_smbios1_serial()
> +                            . ",base64=1";
why add the base64 here - the commit introducing it mentions embedded
nul-bytes:

>                      }
>  
>                      if (
> diff --git a/src/PVE/CLI/qm.pm b/src/PVE/CLI/qm.pm
> index bdae9641..44c74eed 100755
> --- a/src/PVE/CLI/qm.pm
> +++ b/src/PVE/CLI/qm.pm
> @@ -912,7 +912,10 @@ __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();
> +            $conf->{smbios1} =
> +                PVE::QemuServer::generate_smbios1_uuid() . ","
> +                . PVE::QemuServer::generate_smbios1_serial()
> +                . ",base64=1";
>              PVE::QemuConfig->write_config($vmid, $conf);
>  
>              foreach my $disk (@{ $parsed->{disks} }) {
> diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
> index 545758dc..a8cc7d85 100644
> --- a/src/PVE/QemuServer.pm
> +++ b/src/PVE/QemuServer.pm
> @@ -8086,6 +8086,12 @@ sub generate_smbios1_uuid {
>      return "uuid=" . generate_uuid();
>  }
>  
> +sub generate_smbios1_serial {
> +    my @population = ('0' .. '9', 'A' .. 'Z', 'a' .. 'z');
> +    my $serial = join('', map($population[rand(@population)], 1 .. 12));
> +    return "serial=" . encode_base64($serial, "");
> +}
> +
>  sub create_reboot_request {
>      my ($vmid) = @_;
>      open(my $fh, '>', "/run/qemu-server/$vmid.reboot")