From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH 1/2] x86/xen: do not identity map UNUSABLE regions in the machine E820 Date: Fri, 16 Aug 2013 18:20:12 +0100 Message-ID: <520E5F4C.2080006@citrix.com> References: <1376664176-27535-1-git-send-email-david.vrabel@citrix.com> <1376664176-27535-2-git-send-email-david.vrabel@citrix.com> <20130816152356.GC12047@konrad-lan.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130816152356.GC12047@konrad-lan.dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk Cc: Boris Ostrovsky , David Vrabel , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 16/08/13 16:23, Konrad Rzeszutek Wilk wrote: > On Fri, Aug 16, 2013 at 03:42:55PM +0100, David Vrabel wrote: >> From: David Vrabel >> >> If there are UNUSABLE regions in the machine memory map, dom0 will >> attempt to map them 1:1 which is not permitted by Xen and the kernel >> will crash. >> >> There isn't anything interesting in the UNUSABLE region that the dom0 >> kernel needs access to so we can avoid making the 1:1 mapping and >> treat it as RAM. >> >> We only do this for dom0, as we do not expect any domU to ever have a >> UNUSABLE region in their pseudo-physical map. > > Hm, you are going to be disappointed that this is in libxl: The code is fine though since it only messes with UNUSABLE regions for the initial domain. Feel free to fix up the comments and commit description. David