From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Garron Subject: Re: BUG: unable to handle kernel paging request - balloon_init - xen-4.1.0 - 2.6.32.39 Date: Fri, 29 Apr 2011 12:56:40 -0400 Message-ID: <4DBAEDC8.4090102@sce.pridelands.org> References: <4DB60C04.6050802@sce.pridelands.org> <20110426031545.GB20779@dumpdata.com> <4DB6522A.9000304@sce.pridelands.org> <20110427200937.GA19853@dumpdata.com> <4DB8AAA6.4050808@sce.pridelands.org> <20110428183019.GA9852@dumpdata.com 4DBA1EA4.5010004@sce.pridelands.org> 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: Dan Magenheimer Cc: xen-devel@lists.xensource.com, Konrad Wilk List-Id: xen-devel@lists.xenproject.org On 4/29/2011 10:43 AM, Dan Magenheimer wrote: > That multiply is correct. In C, when you add an integer X to a > pointer to a struct of size N, the result is the same as if you were > accessing the Xth element of an array of those structs. Oh yeah! I completely forgot about that. (Haven't done any programming for about six years, so ... rusty) > 1) Is your guest an HVM or PV? IIRC, earlier versions of the > balloon driver did not run properly in an HVM guest. Compare your > source with a latest upstream balloon_init. This machine is too old to have the ability to run a guest as HVM (it's pre-Pacifica/AMD-V), but the problem isn't with running a domU. It won't boot into dom0 (privileged domain) due to this bug. Oddly enough, the build in question *does* work as a PV domU when the hardware is booted to the Debian stock linux-image-xen-amd64 kernel (2.6.32-5-xen-amd64). > 2) Are you building xen/stable-2.6.32.x as the kernel in a guest? > Any chance you might be loading a balloon module that doesn't match > the kernel you built? I'm building the kernel on a separate, faster machine than the one I'm trying to boot it on. I wasn't aware that where it was being built made much of a difference as long as the configured processor type was correct. Both machines are x86_64, but one is Xeon and the other is Opteron. If it does matter where it's built, how do distributions put out pre-compiled dom0 kernels? Also, if it does matter, I can try building it on the slower machine. (The faster one is a production server, so I'm not testing all of these reboots on that) > 3) I think developers generally use the xen/stable-2.6.32.x for dom0 > and use distro kernels (or newer upstream kernels) for guest kernels. > So it is very possible that you are the only one having this problem > because you are the only one using a balloon driver on a > xen/stable-2.6.32.x kernel in a non-dom0 (HVM?) guest. I *am* trying to use it in a dom0 guest. It's: Hardware/BIOS -> Xen4.1 -> this xen/stable-2.6.32.x dom0 -> crash > 4) The latest upstream balloon driver does some magic with the E820 > memory map. Perhaps your machine has an odd or incorrect E820 map > from the BIOS? (This is outside of my area of expertise so apologies > if this doesn't make sense.) I suppose it could be odd. The machine is about 8 years old. I'd imagine that they were doing things a bit differently back then. -- Scott Garron