Re: [PATCH v3 1/9] x86: define CPUINFO_features used as the base offset for cpu features

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 28/04/14 04:13, Feng Wu wrote:
> This patch defines CPUINFO_features which can be used as the base of
> the offset for cpu features.
>
> Signed-off-by: Feng Wu <feng.wu@intel.com>
> ---
>  xen/arch/x86/boot/head.S          | 2 +-
>  xen/arch/x86/x86_64/asm-offsets.c | 2 +-
>  xen/include/asm-x86/asm_defns.h   | 2 ++
>  3 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
> index 1777c17..2b5b26a 100644
> --- a/xen/arch/x86/boot/head.S
> +++ b/xen/arch/x86/boot/head.S
> @@ -131,7 +131,7 @@ __start:
>          mov     $0x80000001,%eax
>          cpuid
>  1:      mov     %edx,sym_phys(cpuid_ext_features)
> -        mov     %edx,sym_phys(boot_cpu_data)+CPUINFO86_ext_features
> +        mov     %edx,sym_phys(boot_cpu_data)+CPUINFO_ext_features

Personally I feel this would be better as CPUINFO_features + 4, rather
than having another #define in asm_defn.h solely for this purpose.

However, functionally it looks fine.

~Andrew

>  
>          /* Check for availability of long mode. */
>          bt      $29,%edx
> diff --git a/xen/arch/x86/x86_64/asm-offsets.c b/xen/arch/x86/x86_64/asm-offsets.c
> index b0098b3..76fafb9 100644
> --- a/xen/arch/x86/x86_64/asm-offsets.c
> +++ b/xen/arch/x86/x86_64/asm-offsets.c
> @@ -159,7 +159,7 @@ void __dummy__(void)
>      OFFSET(IRQSTAT_softirq_pending, irq_cpustat_t, __softirq_pending);
>      BLANK();
>  
> -    OFFSET(CPUINFO86_ext_features, struct cpuinfo_x86, x86_capability[1]);
> +    OFFSET(CPUINFO_features, struct cpuinfo_x86, x86_capability[0]);
>      BLANK();
>  
>      OFFSET(MB_flags, multiboot_info_t, flags);
> diff --git a/xen/include/asm-x86/asm_defns.h b/xen/include/asm-x86/asm_defns.h
> index a4601ba..e8fa989 100644
> --- a/xen/include/asm-x86/asm_defns.h
> +++ b/xen/include/asm-x86/asm_defns.h
> @@ -29,6 +29,8 @@ void ret_from_intr(void);
>      " .previous\n"
>  #endif
>  
> +#define CPUINFO_ext_features (CPUINFO_features+4)
> +
>  #define _ASM_EXTABLE(from, to)     _ASM__EXTABLE(, from, to)
>  #define _ASM_PRE_EXTABLE(from, to) _ASM__EXTABLE(.pre, from, to)
>