Re: [PATCH v2 1/3] x86/match-cpu: Improvements to x86_match_cpu()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 18.07.2025 16:20, Andrew Cooper wrote:
> --- a/xen/arch/x86/cpu/common.c
> +++ b/xen/arch/x86/cpu/common.c
> @@ -1007,19 +1007,26 @@ void cpu_uninit(unsigned int cpu)
>  
>  const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id table[])
>  {
> -     const struct x86_cpu_id *m;
> -     const struct cpuinfo_x86 *c = &boot_cpu_data;
> +    const struct x86_cpu_id *m;
> +    const struct cpuinfo_x86 *c = &boot_cpu_data;
>  
> -     for (m = table; m->vendor | m->family | m->model | m->feature; m++) {
> -             if (c->x86_vendor != m->vendor)
> -                     continue;
> -             if (c->x86 != m->family)
> -                     continue;
> -             if (c->x86_model != m->model)
> -                     continue;
> -             if (!cpu_has(c, m->feature))
> -                     continue;
> -             return m;
> -     }
> -     return NULL;
> +    /*
> +     * Although derived from Linux originally, Xen has no valid rows where
> +     * ->vendor is nonzero, so used this in place of checking all metadata.
> +     */

s/nonzero/zero/, I expect? Then
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

> +    for ( m = table; m->vendor; m++ )
> +    {
> +        if ( c->vendor != m->vendor )
> +            continue;
> +        if ( c->family != m->family )
> +            continue;
> +        if ( c->model != m->model )
> +            continue;
> +        if ( !cpu_has(c, m->feature) )
> +            continue;
> +
> +        return m;
> +    }
> +
> +    return NULL;
>  }