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Date: Mon, 26 May 2014 13:53:39 -0700
From: "H. Peter Anvin" <hpa@linux.intel.com>
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To: "Yu, Fenghua" <fenghua.yu@intel.com>,
        Andy Lutomirski <luto@amacapital.net>, Ingo Molnar <mingo@elte.hu>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Mallick, Asit K" <asit.k.mallick@intel.com>
CC: linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>
Subject: Re: [PATCH 0/15] x86/xsaves: Optimize xstate context switch by xsaves/xrstors
References: <1401123682-5384-1-git-send-email-fenghua.yu@intel.com> <538397F5.6010002@amacapital.net> <3E5A0FA7E9CA944F9D5414FEC6C712205A605703@ORSMSX106.amr.corp.intel.com>
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On 05/26/2014 01:13 PM, Yu, Fenghua wrote:
> 
> So I don't see we need xsaves/xrstors in user space. But I could be
> wrong.
> 

XSAVES/XRSTORS are privileged.  The user-space equivalents are
XSAVEC/XRSTOR.

	-hpa