Re: [Patch v2 08/14] UefiCpuPkg/Include/Register/ArchitecturalMsr.h: Change structure definition.

["Ni, Ruiyu" <ruiyu.ni@Intel.com>]

On 9/21/2018 3:41 PM, Eric Dong wrote:
>       UINT32  User:1;
> -    UINT32  Reserved1:2;
> +    ///
> +    /// [Bit 4] PwrEvtEn.
> +    ///
> +    UINT32  PwrEvtEn:1;
> +    ///
> +    /// [Bit 5] FUPonPTW.
> +    ///
> +    UINT32  FUPonPTW:1;
>       ///
>       /// [Bit 6] FabricEn. If (CPUID.(EAX=07H, ECX=0):ECX[3] = 1).
>       ///
> @@ -4672,7 +4679,10 @@ typedef union {
>       /// [Bit 11] DisRETC.
>       ///
>       UINT32  DisRETC:1;
> -    UINT32  Reserved2:1;
> +    ///
> +    /// [Bit 12] PTWEn.
> +    ///
> +    UINT32  PTWEn:1;
>       ///
>       /// [Bit 13] BranchEn.
>       ///
> @@ -4681,17 +4691,17 @@ typedef union {
>       /// [Bits 17:14] MTCFreq. If (CPUID.(EAX=07H, ECX=0):EBX[3] = 1).
>       ///
>       UINT32  MTCFreq:4;
> -    UINT32  Reserved3:1;
> +    UINT32  Reserved7:1;

I prefer to not change this field name since the bit range for this 
Reserved6 is not changed.

>       ///
>       /// [Bits 22:19] CYCThresh. If (CPUID.(EAX=07H, ECX=0):EBX[1] = 1).
>       ///
>       UINT32  CYCThresh:4;
> -    UINT32  Reserved4:1;
> +    UINT32  Reserved8:1;

I prefer to not change this field name since the bit range for this 
Reserved6 is not changed.

>       ///
>       /// [Bits 27:24] PSBFreq. If (CPUID.(EAX=07H, ECX=0):EBX[1] = 1).
>       ///
>       UINT32  PSBFreq:4;
> -    UINT32  Reserved5:4;
> +    UINT32  Reserved9:4;

I prefer to not change this field name since the bit range for this 
Reserved6 is not changed.

>       ///
>       /// [Bits 35:32] ADDR0_CFG. If (CPUID.(EAX=07H, ECX=1):EAX[2:0] > 0).
>       ///
> @@ -4708,7 +4718,7 @@ typedef union {
>       /// [Bits 47:44] ADDR3_CFG. If (CPUID.(EAX=07H, ECX=1):EAX[2:0] > 3).
>       ///
>       UINT32  ADDR3_CFG:4;
> -    UINT32  Reserved6:16;
> +    UINT32  Reserved10:16;

I prefer to not change this field name since the bit range for this 
Reserved6 is not changed.

>     } Bits;


Eric,
As comments above, I suggest we keep the original Reserved## name if the 
bit range for that field doesn't change. We can only update the 
Reserved## name if the bit range changes.

In this way, we can maximally avoid build failure and also avoid silent 
failure.

In general, the Reserved## name is updated when the bit range changes.
The ## is updated to
1 + MAX (all numbers used by Reserved## in this structure).


Laszlo,
What's your opinion?

-- 
Thanks,
Ray