Re: [PATCH qemu-server] cpu config: Add 'arch' property to cpu_fmt

[Arthur Bied-Charreton <a.bied-charreton@proxmox.com>]

On Mon, Feb 16, 2026 at 02:51:10PM +0100, Fiona Ebner wrote:
> Am 16.02.26 um 12:10 PM schrieb Arthur Bied-Charreton:
> > Preparatory step for adding support for configuring custom CPU types in
> > the PVE UI.
> > 
> > Add optional property 'arch' (x86_64|aarch64) to cpu_fmt to allow custom
> > models to indicate which architecture they belong to. 'arch' defaults to
> > x86_64 for backwards compatibility.
> > 
> > Update get_cpu_models to only return custom models that match the
> > arch to allow querying custom models for a given host architecture.
> > 
> 
> Please also add a check in validate_cpu_conf() that the 'reported-model'
> is available for the configured architecture. It's nicer UX if this
> fails early when configuring rather than only later when using.
> 
> get_cpu_options() could also get a check that the arch of the custom
> model matches the VM arch.
> 
> > Signed-off-by: Arthur Bied-Charreton <a.bied-charreton@proxmox.com>
> > ---
> >  src/PVE/QemuServer/CPUConfig.pm | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/src/PVE/QemuServer/CPUConfig.pm b/src/PVE/QemuServer/CPUConfig.pm
> > index 32ec4954..728c5562 100644
> > --- a/src/PVE/QemuServer/CPUConfig.pm
> > +++ b/src/PVE/QemuServer/CPUConfig.pm
> > @@ -374,6 +374,13 @@ my $cpu_fmt = {
> >              . " note that doing so will break live migration to CPUs with other values.",
> >          optional => 1,
> >      },
> > +    arch => {
> 
> To avoid getting out of sync, you could re-use the existing
> 'pve-qm-cpu-arch' standard option, overwriting the 'description',
> 'default' and 'optional' properties.
> 
> > +        type => 'string',
> > +        enum => [qw(x86_64 aarch64)],
> > +        default => 'x86_64',
> > +        description => 'The architecture the CPU model belongs to.',
> > +        optional => 1,
> > +    },
> >  };
> >  
> >  my $sev_fmt = {
> > @@ -612,9 +619,14 @@ sub get_cpu_models {
> >  
> >      my $conf = load_custom_model_conf();
> >      for my $custom_model (keys %{ $conf->{ids} }) {
> > +        my $custom_model_arch = $conf->{ids}->{$custom_model}->{'arch'};
> > +        $custom_model_arch //= $cpu_fmt->{'arch'}->{default};
> 
> Style nit: we usually avoid single quotes when not needed for hash keys.
> Note that you are not doing it for 'default' either. It's easier to read
> if consistent with the other code in the module.
> 
> > +        next if ($custom_model_arch ne $arch);
> 
> Style nit: no need for parentheses for post-if expression
> 
> > +
> >          my $reported_model = $conf->{ids}->{$custom_model}->{'reported-model'};
> >          $reported_model //= $cpu_fmt->{'reported-model'}->{default};
> >          my $vendor = $all_cpu_models->{$reported_model};
> > +
> >          push @$models,
> >              {
> >                  name => "custom-$custom_model",
>
Hey Fiona, thanks a lot for the feedback, addressed in v2:
https://lore.proxmox.com/pve-devel/20260217084105.72579-1-a.bied-charreton@proxmox.com/T/#t