From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH 02/11] KVM: x86: tag the instructions which are used to
 write page table
Date: Mon, 22 Aug 2011 11:32:35 -0300
Message-ID: <20110822143235.GA4797@amt.cnet>
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 <4E4A1117.1030608@cn.fujitsu.com>
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Cc: Avi Kivity <avi@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
	KVM <kvm@vger.kernel.org>
To: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
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On Tue, Aug 16, 2011 at 02:41:27PM +0800, Xiao Guangrong wrote:
> The idea is from Avi:
> | tag instructions that are typically used to modify the page tables, and
> | drop shadow if any other instruction is used.
> | The list would include, I'd guess, and, or, bts, btc, mov, xchg, cmpxchg,
> | and cmpxchg8b.
> 
> This patch is used to tag the instructions and in the later path, shadow page
> is dropped if it is written by other instructions

What is the advantage of doing this again? What is the point of
dropping shadow if the instruction is emulated?