Re: [Xen-devel] [PATCH 2/3] x86/xsaves: fix overwriting between non-lazy/lazy xsave[sc]

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 22.02.16 at 06:35, <shuai.ruan@xxxxxxxxxxxxxxx> wrote:

First of all I wonder on what basis you collect your Cc lists on
patches.

> --- a/xen/arch/x86/i387.c
> +++ b/xen/arch/x86/i387.c
> @@ -118,7 +118,7 @@ static inline uint64_t vcpu_xsave_mask(const struct vcpu 
> *v)
>      if ( v->fpu_dirtied )
>          return v->arch.nonlazy_xstate_used ? XSTATE_ALL : XSTATE_LAZY;
>  
> -    return v->arch.nonlazy_xstate_used ? XSTATE_NONLAZY : 0;
> +    return ( cpu_has_xsaves || cpu_has_xsavec ) ? XSTATE_ALL : 
> XSTATE_NONLAZY;
>  }

The description lacks any mention of the performance impact,
and what investigation was done to find ways to perhaps
overcome this. For example, regardless of cpu_has_xsaves,
do we really always need to _use_ XSAVES?

Also - coding style (stray spaces inside parentheses).

Jan


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