From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Bainbridge Subject: Re: can't boot dom0 Date: Thu, 6 Oct 2005 08:58:16 +0100 Message-ID: <623652d50510060058p30ecd783i@mail.gmail.com> References: <983B408465C04C49B0344D51FA21C7553E74FC@trudi.bpmmail.local> <623652d50510051132t2399d058m@mail.gmail.com> <364032b989f0c3bc7a785c4b0594d1f1@cl.cam.ac.uk> Reply-To: Chris Bainbridge Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <364032b989f0c3bc7a785c4b0594d1f1@cl.cam.ac.uk> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: xen-devel List-Id: xen-devel@lists.xenproject.org On 05/10/05, Keir Fraser wrote: > > On 5 Oct 2005, at 19:32, Chris Bainbridge wrote: > > > Ah-ha! So it looks like you need CONFIG_X86_UP_IOAPIC or SMP to get it > > working. > > > > Bug 1) xen with non apic kernel is broken > > Bug 2) compile error with CONFIG_PCI_MSI > > Trying to boot an SMP system with a non-APIC domain0 is a recipe for > disaster. We depend an awful lot on domain0 to get interrupt routing > correct. If Xen has booted an SMP system, probed IO-APICs and so on, > domain0 needs to have the same world view. > > The 'bug' is really that we don't make it harder for people to shoot > themselves in the foot in their configuration. Possibly forcing the > APIC options is the way to go, or at least indicate that setting them > to N is DANGEROUS. In my case "SMP" was just uniprocessor hyperthreading, not really SMP, so I expected it to work. It's a non-obvious error that will trip up a lot of people, I'd recommend forcing it, or detecting the hypervisor/kernel SMP mismatch at boottime and printing a big warning.