From mboxrd@z Thu Jan 1 00:00:00 1970 From: tgh Subject: question about the differences for xen in x86_32 and x86_64 Date: Thu, 17 May 2007 16:53:59 +0800 Message-ID: <464C1827.4020602@ncic.ac.cn> References: <200705170825.l4H8PsrQ009170@fjmscan503.ms.jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <200705170825.l4H8PsrQ009170@fjmscan503.ms.jp.fujitsu.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org =BE hi I am confused about the differences betwoon xen in x86_32 and x86_64 in x86_32,Ring 1 for guest OS, ring3 for user-space, Xen lives in top=20 64MB of linear addr space, Segmentation used to protect Xen as switching=20 page tables too slow on standard x86, Hypercalls jump to Xen in ring 0,=20 Guest OS with =91fast trap=92 handler could direct user-space to guest OS= =20 system calls, is it right? while in x86_64 ,both guestos and userapplications seem to run in ring3,=20 and what about other thing memtioned above for x86_64? such as the=20 memory mapping for xen and guestos kernel and applications , system call=20 fast trap handling I am confused about it could you help me Thanks in advance