From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v2 3/3] X86, mpx: Intel MPX xstate feature definition
Date: Fri, 06 Dec 2013 09:55:12 -0800
Message-ID: <52A20F80.9000601@zytor.com>
References: <1386375658-2191-1-git-send-email-qiaowei.ren@intel.com> <1386375658-2191-3-git-send-email-qiaowei.ren@intel.com> <52A20AD6.8080706@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-15
Content-Transfer-Encoding: 7bit
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, x86@kernel.org,
	linux-kernel@vger.kernel.org, qemu-devel@nongnu.org,
	kvm@vger.kernel.org, Xudong Hao <xudong.hao@intel.com>,
	Liu Jinsong <jinsong.liu@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Qiaowei Ren <qiaowei.ren@intel.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <52A20AD6.8080706@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On 12/06/2013 09:35 AM, Paolo Bonzini wrote:
> 
> Sorry for the back-and-forth, but I think this and the removal of
> XSTATE_FLEXIBLE (perhaps XSTATE_LAZY?) makes your v2 worse than v1.
> 
> Since Peter already said the same, please undo these changes.
> 
> Also, how is XSTATE_EAGER used?  Should MPX be disabled when xsaveopt is
> disabled on the kernel command line?  (Liu, how would this affect the
> KVM patches, too?)
> 

There are two options: we could disable MPX etc. or we could force eager
saving (using xsave) even if xsaveopt is disabled.  It is a hard call to
make, but I guess I'm leaning towards the latter; we could add an
"lazyxsave" option to explicitly disable all eager features if there is
use for that.

	-hpa