From mboxrd@z Thu Jan 1 00:00:00 1970 From: tgh Subject: question about memory auto-translate and paravirtual and no pseudophysical overlay Date: Tue, 03 Apr 2007 10:59:03 +0800 Message-ID: <4611C2F7.9060800@ncic.ac.cn> References: <991B62EB36934C4EBD5B605518A724764C421E@pdsmsx404.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <991B62EB36934C4EBD5B605518A724764C421E@pdsmsx404.ccr.corp.intel.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 hi I try to understand the code of xen memory there are gmfn, gpfn and pfn in the xen and in the /xen/include/xen/mm.h there are some explanation about them as follows: * 1. gpfn/gpaddr: A guest-specific pseudo-physical frame number or address. * 2. gmfn/gmaddr: A machine address from the p.o.v. of a particular guest. * 3. mfn/maddr: A real machine frame number or address. * 4. pfn/paddr: Used in 'polymorphic' functions that work across all * address spaces, depending on context. See the pagetable * conversion macros in asm-x86/page.h for examples. * Also 'paddr_t' is big enough to store any physical address. * I seems to understand the meaning about them,but I am confused about the different memory-management modes as follows * This scheme provides consistent function and variable names even when * different guests are running in different memory-management modes. * 1. A guest running in auto-translated mode (e.g., shadow_mode_translate()) * will have gpfn == gmfn and gmfn != mfn. * 2. A paravirtualised x86 guest will have gpfn != gmfn and gmfn == mfn. * 3. A paravirtualised guest with no pseudophysical overlay will have * gpfn == gpmfn == mfn. * what is the meaning about auto-translated mode,is it not the same with paravirtualised one ? does the auto-translated mode work for hvm and shadow mode? how does it work? and what is the mechanism about paravirtualised guest with no pseudophysical overlay? I am confused about it could you help me Thanks in advance