From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH] Fix emergency_restart (sysrq-b) with kvm loaded on Intel hosts Date: Mon, 25 Aug 2008 11:30:20 +0200 Message-ID: <20080825093020.GA5617@elte.hu> References: <1219655506-27418-1-git-send-email-avi@qumranet.com> <20080825091508.GC9114@elte.hu> <48B27AFE.3080704@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx2.mail.elte.hu ([157.181.151.9]:44208 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753828AbYHYJad (ORCPT ); Mon, 25 Aug 2008 05:30:33 -0400 Content-Disposition: inline In-Reply-To: <48B27AFE.3080704@qumranet.com> Sender: kvm-owner@vger.kernel.org List-ID: * Avi Kivity wrote: > Ingo Molnar wrote: >> * Avi Kivity wrote: >> >> >>> Enabling Intel VT has the curious side effect whereby the INIT signal >>> is blocked. Rather than comment on the wisdom of this side effect, >>> this patch adds an emergency restart reboot notifier, and modifies >>> the kvm reboot notifier to disable VT on emergency reboot. >>> >> >> looks good to me - i was bitten by that problem on a testbox. >> > > I'm a little worried about making emergency restart more complex. > > Another thing that worries me is that emergency_restart() doesn't > reset the box -- it sends INIT. We could do better by using the ACPI > FADT reset register (hopefully that's connected to RESET). reboot was always a bit fragile - i think we should only do that if we find a box where the FADT reset works better than the first-wave approaches we try. > Which seems to be what we want? Maybe we should just try acpi_reboot() > before the other stuff. perhaps in a separate commit, for v2.6.28 at the earliest. Ingo