Re: [PATCH v2 01/74] x86/cpu/vfm: Add/initialize x86_vfm field to struct cpuinfo_x86

[Thomas Gleixner]

On Mon, Apr 01 2024 at 11:23, Tony Luck wrote:

> Refactor struct cpuinfo_x86 so that the vendor, family, and model
> fields are overlayed in a union with a 32-bit field that combines
> all three (together with a one byte reserved field in the upper
> byte).
>
> This will make it easy, cheap, and reliable to check all three
> values at once.
>
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

> ---
>  arch/x86/include/asm/processor.h | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 811548f131f4..4c5d166aa473 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -108,9 +108,15 @@ struct cpuinfo_topology {
>  };
>  
>  struct cpuinfo_x86 {
> -	__u8			x86;		/* CPU family */
> -	__u8			x86_vendor;	/* CPU vendor */
> -	__u8			x86_model;
> +	union {
> +		struct {
> +			__u8	x86_model;
> +			__u8	x86;		/* CPU family */
> +			__u8	x86_vendor;	/* CPU vendor */
> +			__u8	x86_reserved;
> +		};
> +		__u32		x86_vfm;	/* combined vendor, family, model */
> +	};
>  	__u8			x86_stepping;
>  #ifdef CONFIG_X86_64
>  	/* Number of 4K pages in DTLB/ITLB combined(in pages): */