From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 0/2] Introduce panic hypercall Date: Mon, 20 Jun 2011 19:13:52 +0200 Message-ID: <4DFF7FD0.4070002@siemens.com> References: <1308577094-17551-1-git-send-email-gollub@b1-systems.de> <20110620153825.GH13042@redhat.com> <4DFF6B20.7090107@redhat.com> <201106201826.32975.gollub@b1-systems.de> <4DFF76B1.8020509@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Daniel Gollub , "Daniel P. Berrange" , kvm@vger.kernel.org, qemu-devel To: Avi Kivity Return-path: Received: from david.siemens.de ([192.35.17.14]:18352 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751197Ab1FTROE (ORCPT ); Mon, 20 Jun 2011 13:14:04 -0400 In-Reply-To: <4DFF76B1.8020509@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2011-06-20 18:34, Avi Kivity wrote: >> > >> > Do ILO cards / IPMI support something like this? We could follow >> their >> > lead in that case. >> >> The only two things which came to my mind are: >> >> * NMI (aka. ipmitool diag) - already available in qemu/kvm - but >> requires >> in-guest kexec/kdump >> * Hardware-Watchdog (also available in qemu/libvirt) > > A watchdog has the advantage that is also detects lockups. > > In fact you could implement the panic device via the existing > watchdogs. Simply program the timer for the minimum interval and > *don't* service the interrupt. This would work for non-virt setups as > well as another way to issue a reset. If you manage to bring down the other guest CPUs fast enough. Otherwise, they may corrupt your crashdump before the host had a chance to collect all pieces. Synchronous signaling to the hypervisor is a bit safer. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux