Re: [XEN PATCH v1 13/15] x86: wire cpu_has_{svm/vmx}_* to false when svm/vmx not enabled

[Jan Beulich]

On 16.04.2024 08:46, Sergiy Kibrik wrote:
> --- a/xen/arch/x86/include/asm/hvm/svm/svm.h
> +++ b/xen/arch/x86/include/asm/hvm/svm/svm.h
> @@ -38,10 +38,18 @@ extern u32 svm_feature_flags;
>  #define SVM_FEATURE_SSS           19 /* NPT Supervisor Shadow Stacks */
>  #define SVM_FEATURE_SPEC_CTRL     20 /* MSR_SPEC_CTRL virtualisation */
>  
> +#ifdef CONFIG_SVM
>  static inline bool cpu_has_svm_feature(unsigned int feat)
>  {
>      return svm_feature_flags & (1u << feat);
>  }
> +#else
> +static inline bool cpu_has_svm_feature(unsigned int feat)
> +{
> +    return false;
> +}
> +#endif

Already

static inline bool cpu_has_svm_feature(unsigned int feat)
{
#ifdef CONFIG_SVM
     return svm_feature_flags & (1u << feat);
#else
    return false;
#endif
}

would be less redundancy. But why not simply

static inline bool cpu_has_svm_feature(unsigned int feat)
{
     return is_ENABLED(CONFIG_SVM) && (svm_feature_flags & (1u << feat));
}

?

Jan