From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tim Deegan <Tim.Deegan@citrix.com>
Subject: Re: where is writable page table implemented?
Date: Tue, 1 Apr 2008 08:38:25 +0000
Message-ID: <20080401083825.GA4628@york.uk.xensource.com>
References: <add59a3f0803240918m1f882115h7c2ba64e2ca2139a@mail.gmail.com>
	<20080324162510.GD30315@york.uk.xensource.com>
	<add59a3f0803241126i603eb40qfa1b57f917103e74@mail.gmail.com>
	<20080325104351.GA30991@york.uk.xensource.com>
	<add59a3f0803301643r740ba4c5xda84c40b46d7a157@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Return-path: <xen-devel-bounces@lists.xensource.com>
Content-Disposition: inline
In-Reply-To: <add59a3f0803301643r740ba4c5xda84c40b46d7a157@mail.gmail.com>
List-Unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: weiming <zephyr.zhao@gmail.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
List-Id: xen-devel@lists.xenproject.org

At 19:43 -0400 on 30 Mar (1206906207), weiming wrote:
> with writable page table, why guest os still calls update_va_mapping to
> update the pte? 

It's faster to call into Xen with an explicit modification, or a list of
them, than to have xen trap and do a full x86 instruction emaulation to
figure out what you werere doing.

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, Citrix Systems (R&D) Ltd.
[Company #02300071, SL9 0DZ, UK.]