Re: [PATCH 2/5] x86/asm: Split __wr{fs,gs}base() out of write_{fs,gs}_base()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 09.09.2020 11:59, Andrew Cooper wrote:
> To match the read side which is already split out.  A future change will want
> to use them.
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
Of course ...

> --- a/xen/include/asm-x86/msr.h
> +++ b/xen/include/asm-x86/msr.h
> @@ -156,6 +156,24 @@ static inline unsigned long __rdgsbase(void)
>      return base;
>  }
>  
> +static inline void __wrfsbase(unsigned long base)
> +{
> +#ifdef HAVE_AS_FSGSBASE
> +    asm volatile ( "wrfsbase %0" :: "r" (base) );
> +#else
> +    asm volatile ( ".byte 0xf3, 0x48, 0x0f, 0xae, 0xd0" :: "a" (base) );
> +#endif
> +}
> +
> +static inline void __wrgsbase(unsigned long base)
> +{
> +#ifdef HAVE_AS_FSGSBASE
> +    asm volatile ( "wrgsbase %0" :: "r" (base) );
> +#else
> +    asm volatile ( ".byte 0xf3, 0x48, 0x0f, 0xae, 0xd8" :: "a" (base) );
> +#endif
> +}

... I'd have preferred if you had used just a single leading
underscore, despite realizing this would introduce an inconsistency
with the read sides.

Jan