Re: [PATCH 05/32] x86/mtrr: Stop using 32-bit MSR interfaces

[Ingo Molnar]

* Juergen Gross <jgross@xxxxxxxx> wrote:

>  amd_get_mtrr(unsigned int reg, unsigned long *base,
>  	     unsigned long *size, mtrr_type *type)
>  {
> -	unsigned long low, high;
> +	unsigned long val;
> +	struct msr msr;

So, 'struct msr' is defined in <asm/msr.h>, but:

>  static void
>  amd_set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type)
>  {
> -	u32 regs[2];
> +	union {
> +		u32 regs[2];
> +		u64 val;
> +	} msr;

Why do we use a local anonymous union here with overlapping
nomenclature and a confusingly different but (AFAICS) functionally
equivalent definition to 'struct msr'?

Thanks,

	Ingo