From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH v2 2/8] tools: arm: report an error if the guest RAM is too large Date: Fri, 25 Apr 2014 13:04:22 +0100 Message-ID: <1398427462.18537.440.camel@kazak.uk.xensource.com> References: <1398424945.18537.424.camel@kazak.uk.xensource.com> <1398424967-9306-2-git-send-email-ian.campbell@citrix.com> <535A4C08.6000108@linaro.org> <1398426699.18537.433.camel@kazak.uk.xensource.com> <535A4EB3.1050903@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <535A4EB3.1050903@linaro.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Julien Grall Cc: ian.jackson@eu.citrix.com, stefano.stabellini@eu.citrix.com, tim@xen.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Fri, 2014-04-25 at 13:01 +0100, Julien Grall wrote: > > On 25/04/14 12:51, Ian Campbell wrote: > > On Fri, 2014-04-25 at 12:50 +0100, Julien Grall wrote: > >> Hi Ian, > >> > >> On 25/04/14 12:22, Ian Campbell wrote: > >>> Due to the layout of the guest physical address space we cannot support more > >>> than 768M of RAM before overrunning the area set aside for the grant table. Due > >>> to the presence of the magic pages at the end of the RAM region guests are > >>> actually limited to 767M. > >>> > >>> Catch this case during domain build and fail gracefully instead of obscurely > >>> later on. > >>> > >>> Signed-off-by: Ian Campbell > >>> --- > >>> This is the only patch in this series which I consider to be suitable for > >>> backporting to Xen 4.4 > >> > >> I agree with you. Without this the guest can crash with weird error. > > > > I've found that it just hangs silently, which is even more frustrating. > > When I try to create a domain with 800M of RAM I get some error from libxl: With 768M I get a hang. > libxl: notice: libxl_numa.c:494:libxl__get_numa_candidate: NUMA placement failed, performance might be affected > libxl: error: libxl_device.c:934:device_backend_callback: unable to add device with path /local/domain/0/backend/vbd/5/51712 > libxl: error: libxl_create.c:1062:domcreate_launch_dm: unable to add disk devices > libxl: error: libxl_device.c:934:device_backend_callback: unable to remove device with path /local/domain/0/backend/vbd/5/51712 > libxl: error: libxl.c:1470:devices_destroy_cb: libxl__devices_destroy failed for 5 > >