From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [V3 PATCH 6/9] x86/hvm: pkeys,
 add xstate support for pkeys
Date: Fri, 11 Dec 2015 02:36:51 -0700
Message-ID: <566AA74302000078000BE88C@prv-mh.provo.novell.com>
References: <1449479780-19146-1-git-send-email-huaitong.han@intel.com>
	<1449479780-19146-7-git-send-email-huaitong.han@intel.com>
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To: Huaitong Han <huaitong.han@intel.com>
Cc: kevin.tian@intel.com, wei.liu2@citrix.com, ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, george.dunlap@eu.citrix.com, andrew.cooper3@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xen.org, jun.nakajima@intel.com, keir@xen.org
List-Id: xen-devel@lists.xenproject.org

>>> On 07.12.15 at 10:16, <huaitong.han@intel.com> wrote:
> --- a/xen/arch/x86/xstate.c
> +++ b/xen/arch/x86/xstate.c
> @@ -146,12 +146,15 @@ static void __init setup_xstate_comp(void)
>      }
>  }
>  
> -static void *get_xsave_addr(void *xsave, unsigned int xfeature_idx)
> +void *get_xsave_addr(void *xsave, unsigned int xfeature_idx)
>  {
>      if ( !((1ul << xfeature_idx) & xfeature_mask) )
>          return NULL;
>  
> -    return xsave + xstate_comp_offsets[xfeature_idx];
> +    if ( xsave_area_compressed(xsave) )
> +        return xsave + xstate_comp_offsets[xfeature_idx];
> +    else
> +        return xsave + xstate_offsets[xfeature_idx];

For constructs like this I'd really like to ask to avoid as much of the
redundancy as possible. The most compact form would probably be

        return xsave + (xsave_area_compressed(xsave)
                        ? xstate_comp_offsets
                        : xstate_offsets)[xfeature_idx];

But at the very least the "else" should go away.

Jan