From mboxrd@z Thu Jan 1 00:00:00 1970 From: Min Lee Subject: Re: [Q] mfn_to_gmfn macro, log-dirty bitmap, Date: Mon, 28 Jun 2010 10:25:59 -0400 Message-ID: <4C28B0F7.3040509@gatech.edu> References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: 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, thanks, but I don't understand. dinfo->p2m_size:67584, (XEN) addr:bff25000 accessible, mfn:5f8eb, gmfn:5f8eb (XEN) addr:bff26000 accessible, mfn:6e003, gmfn:6e003 (XEN) addr:bff27000 accessible, mfn:425da, gmfn:425da This domain has 256MB ram (67584 frames, slightly more than 65536) as p2m_size indicates, and I have dirty-bit bitmap which I believe has 67584 bits. but In this case above, three frames has mfn of 0x5f8eb, 0x6e003, 0x425da which I cannot use as index in my dirt_bit bitmap. I understand PV guest directly use mfn into page table entry, but regarding log-dirt-bit bitmap, I think I need gmfn index here. Am I misunderstanding something? What I'm doing is to read dirty bit for my virtual frame. so I need know which bit in log-dirty bit corresponds to my virtual frame. Thanks Min On 6/28/2010 9:50 AM, Keir Fraser wrote: > On 28/06/2010 14:40, "Min Lee" wrote: > >> I'm running 32bit PV-domu on 64bit xen&dom0 and I'm using >> XEN_DOMCTL_SHADOW_OP_PEEK to get log-dirty bitmap. >> First, I'm assuming this bitmap is indexed by gmfn, right? because we're >> passing p2m->size parameter to xen. >> Second, I have mfn (not gmfn) which I want to translate to gmfn so that I >> can correctly read corresponding bit in log-dirty bitmap. so I've tried >> mfn_to_gmfn() macro below but it doesn't seem to work. (always mfn==gmfn) >> Maybe because m2p table is not enabled? >> How can I properly do mfn_to_gmfn? > > For a PV guest, GMFN and MFN are equivalent. > > -- Keir > > >