From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: several Qs about domain live migration Date: Tue, 18 Nov 2008 08:13:11 +0000 Message-ID: References: <20081118011724.GA8523@edwin-srv.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081118011724.GA8523@edwin-srv.sh.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: "Zhai, Edwin" Cc: "Tian, Kevin" , Xen Developers List-Id: xen-devel@lists.xenproject.org On 18/11/08 01:17, "Zhai, Edwin" wrote: > We are trying to fix a HVM live migration bug, and found "Use main memory for > video memory" in r18383 cause guest hang after restore. > > Following changes make all valid pages migrated, including vlapic page > (0xFEE00), and share page(0xFFFFF), so an extra memory population for these 2 > pages would override previous mapping then cause guest hang (if using vlapic > acceleration). > > What do you think of possible fixing? Skipping these specific pages in > xc_domain_save except video memory, or change the HVM domain creation. Try changing gmfn_to_mfn(FOREIGNDOM, l1e_get_pfn(nl1e)) in mod_l1_entry() to: mfn = gfn_to_mfn(FOREIGNDOM, l1e_get_pfn(nl1e), &p2mt); if ( !p2m_is_ram(p2mt) || (mfn == INVALID_MFN) ) .... This will prevent foreign mappings of 'mmio' pages. Pretty sensible and will fix this problem. -- Keir