From mboxrd@z Thu Jan 1 00:00:00 1970 From: tgh Subject: Re: page table question! Date: Sun, 16 Dec 2007 11:07:49 +0800 Message-ID: <47649685.2030709@ncic.ac.cn> References: <907625E08839C4409CE5768403633E0B02561E12@sefsexmb1.amd.com> <200706131735.30820.mark.williamson@cl.cam.ac.uk> <20070614082755.GB15027@york.uk.xensource.com> <475AA9A9.4050103@sina.com.cn> <1197125421.27734.13.camel@thinkpad.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <1197125421.27734.13.camel@thinkpad.localdomain> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Daniel Stodden Cc: xen-devel@lists.xensource.com, Tim Deegan , Tim Deegan , MT Rezaie , "Petersson, Mats" , Mark Williamson List-Id: xen-devel@lists.xenproject.org some issues are still confuesed , Daniel Stodden =E5=86=99=E9=81=93: > =20 >> then there will not be a small mount of memory consumption for=20 >> hyperviser's limited VA ,is it? or where are those counterpart page=20 >> tables stored ? >> =20 > > Or do you mean the part of the VM dedicated to the hypervisor? Code > running in root mode is running in "host linear" address space, i.e. th= e > nested page table, not the guest's one. Actually, that's one major > benefit of nested paging: counteraction "address space compression". > =20 nested page table ,for the AMD NPT ,is stored in the dom0 linear space,=20 not in the hypervisor virtual address ,is it? or what is the meaning of=20 "that's one major benefit of nested paging: counteraction "address space=20 compression".",and what about the Intel EPT, is it similar ,or how does=20 it work, I am still comfused about the hypervisor' limited virtual=20 address space, it wont be used for storing the EPT or NPT, is it? or=20 what about the hypervisor's virtual address space in the AMD or=20 Intel-vt?how much space is it? or what is tricks behind, could you give=20 me a more detailed explanation about NPT and EPT another one ,"the guest system takes two levels of translation, while=20 the host(Xen, in this case) takes only one" , what is the meaning? guest=20 does virtual->physical, while physical->machine is translated by xen, is=20 it? what is the tricks, by say, guest takes two levels of translation? Thanks in advance > So, the guest system takes two levels of translation, while the host > (Xen, in this case) takes only one. > > Hope this helps. Clarify your question if it doesn't. > > regards, > daniel > > =20