linux-kernel - Re: [PATCH] x86/fpu/xstate: Return error if xfeature bit is unset in XSAVES compacted-format buffer

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Date:	Wed, 27 Jul 2016 11:00:28 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org,
	Dave Hansen <dave.hansen@...el.com>,
	Yu-Cheng Yu <yu-cheng.yu@...el.com>,
	Fenghua Yu <fenghua.yu@...el.com>,
	Ravi Shankar <ravi.v.shankar@...el.com>
Subject: Re: [PATCH] x86/fpu/xstate: Return error if xfeature bit is unset in
 XSAVES compacted-format buffer


* Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com> wrote:

> From: Sai Praneeth <sai.praneeth.prakhya@...el.com>
> 
> Currently, XSAVES compacted-format buffer will always contain space for
> all enabled states. If XSAVES compacted-format buffer is in use and
> an xstate component (E.g: PKRU xstate) is not present in the buffer
> (i.e. xcomp_bv does not have xfeature (E.g: XFEATURE_MASK_PKRU) bit
> set), then fpu__xfeature_set_state() returns error.

Please fix the changelog to conform to the standard changelog style:

 - first describe the symptoms of the bug - how does a user notice? 

 - then describe how the code behaves today and how that is causing the bug

 - and then only describe how it's fixed.

Thanks,

        Ingo