From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56862) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VCb5t-00073U-Fw for qemu-devel@nongnu.org; Thu, 22 Aug 2013 16:03:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VCb5o-0000ru-Co for qemu-devel@nongnu.org; Thu, 22 Aug 2013 16:02:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55040) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VCb5o-0000ra-4v for qemu-devel@nongnu.org; Thu, 22 Aug 2013 16:02:52 -0400 Message-ID: <52166E68.5070609@redhat.com> Date: Thu, 22 Aug 2013 14:02:48 -0600 From: Eric Blake MIME-Version: 1.0 References: <1377187852-11192-1-git-send-email-pbonzini@redhat.com> <5216471E.7020209@redhat.com> <5216642A.7010503@redhat.com> <52166974.4030703@redhat.com> In-Reply-To: <52166974.4030703@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="kXklX7WPollvHUv0vaaPQfE4JhiJ3QHnP" Subject: Re: [Qemu-devel] [libvirt] pvpanic plans? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laszlo Ersek Cc: pkrempa@redhat.com, marcel.a@redhat.com, libvir-list@redhat.com, mst@redhat.com, qemu-devel@nongnu.org, rhod@redhat.com, anthony@codemonkey.ws, Paolo Bonzini , afaerber@suse.de This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --kXklX7WPollvHUv0vaaPQfE4JhiJ3QHnP Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 08/22/2013 01:41 PM, Laszlo Ersek wrote: > On 08/22/13 21:19, Paolo Bonzini wrote: >> Il 22/08/2013 19:15, Laszlo Ersek ha scritto: >>>> 2) On all versions, will only work if the element is ther= e. >>> >>> I like this, because, if on_crash doesn't work without panic_notifier= >>> *at all*, then we can just drop panic_notifier, and make on_crash mea= n >>> (on_crash && panic_notifier) in the original sense. >>> >>> IOW, drop "panic_notifier", and make "on_crash" work *always*. >> >> No, we cannot because of backwards compatibility. VMs could have no >> on_crash element (which means destroy) and yet th= e >> guest admin could expect them to reboot on panic. >=20 > Ah. I thought "no on_crash" meant ignore, or > something like that -- if on_crash was absent, the guest wouldn't see a= > working pvpanic device in ACPI, and wouldn't trigger the event in qemu.= Unfortunately, ignore does not exist in current libvirt codebase, and is always present on output (if omitted on input, it is present as destroy on output; but MOST vms have it as restart thanks to virt-install's defaults). In short, libvirt's problem is that older libvirt basically ignored the setting (whether default of destroy or set by virt-manager to restart), BOTH of those common options are most sensibly implemented by having a panic device, but adding a panic device is guest visible, and therefore must be controlled by some NEW piece of XML. If we add ignore