Re: [Xen-devel] [V2 PATCH 6/9] x86/hvm: pkeys, add functions to support PKRU access

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 27/11/15 09:52, Huaitong Han wrote:
> This patch adds functions to support PKRU access.
>
> Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx>
> ---
>  xen/include/asm-x86/processor.h | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
> index 3f8411f..68d86cb 100644
> --- a/xen/include/asm-x86/processor.h
> +++ b/xen/include/asm-x86/processor.h
> @@ -342,6 +342,21 @@ static inline void write_cr4(unsigned long val)
>      asm volatile ( "mov %0,%%cr4" : : "r" (val) );
>  }
>  
> +/* Macros for PKRU domain */
> +#define PKRU_READ  0
> +#define PKRU_WRITE 1
> +#define PKRU_ATTRS 2
> +
> +/*
> + * PKRU defines 32 bits, there are 16 domains and 2 attribute bits per
> + * domain in pkru, pkeys is index to a defined domain, so the value of
> + * pte_pkeys * PKRU_ATTRS + R/W is offset of a defined domain attribute.
> + */
> +#define READ_PKRU_AD(pkru, pkey) \
> +    ((pkru >> (pkey * PKRU_ATTRS + PKRU_READ)) & 1)
> +#define READ_PKRU_WD(pkru, pkey) \
> +    ((pkru >> (pkey * PKRU_ATTRS + PKRU_WRITE)) & 1)

Both macro parameters need quoting, but these would be better still as
static inline functions.

~Andrew

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