From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35025) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vbtq7-0001eN-Db for qemu-devel@nongnu.org; Thu, 31 Oct 2013 11:07:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vbtq2-0008DW-EV for qemu-devel@nongnu.org; Thu, 31 Oct 2013 11:07:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49637) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vbtq2-0008DL-4v for qemu-devel@nongnu.org; Thu, 31 Oct 2013 11:07:10 -0400 Date: Thu, 31 Oct 2013 17:09:55 +0200 From: "Michael S. Tsirkin" Message-ID: <20131031150955.GE9948@redhat.com> References: <1377187852-11192-1-git-send-email-pbonzini@redhat.com> <20131024023903.GD16757@G08FNSTD100614.fnst.cn.fujitsu.com> <20131031143004.GA9948@redhat.com> <52726A0B.4080805@redhat.com> <52726B95.6020006@redhat.com> <20131031145234.GC9948@redhat.com> <52726FAA.6000502@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52726FAA.6000502@redhat.com> Subject: Re: [Qemu-devel] pvpanic plans? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: pkrempa@redhat.com, lersek@redhat.com, marcel.a@redhat.com, libvir-list@redhat.com, Hu Tao , qemu-devel@nongnu.org, armbru@redhat.com, rhod@redhat.com, kraxel@redhat.com, anthony@codemonkey.ws, lcapitulino@redhat.com, afaerber@suse.de On Thu, Oct 31, 2013 at 03:56:42PM +0100, Paolo Bonzini wrote: > Il 31/10/2013 15:52, Michael S. Tsirkin ha scritto: > >> > Yes, it does. > > What does it break exactly? > > The point of a panicked event is to examine the guest at a particular > moment in time (e.g. host-initiated crash dump). If you let the guest > run, it may reboot and prevent you from getting a meaningful dump. Well we trust guest anyway, so I think we can trust it to call halt. > >> > But I think that, once we make the pvpanic device is > >> > optional, to a large extent there is no bug. Adding the pvpanic > >> > device to the VM will make libvirt obey instead of the > >> > in-guest setting, and that's it. > >> > > >> > Two months have passed and no casualties have been reported due to > >> > pvpanic. Let's just remove the auto-pvpanic from all machine types in > >> > 1.7 (yes, that's backwards incompatible in a strict sense), document > >> > it in the release notes, and hope that the old QEMU versions with > >> > mandatory pvpanic die of old age. > > > > Nod. I'm fine with that. > > > > I think we still need to do get rid of the PANICKED state somehow. > > If we can't replace it with RUNNING state, let's replace it with PAUSED. > > > > For example, you can't continue from panicked for some reason. > > You can't do a reset. But you can pause and then continue. > > We need to keep the PANICKED state, but we can make it a normal > "resumable" state. If it's resumable how is it different from PAUSED? > Basically it's patches 1 and 2 at > http://permalink.gmane.org/gmane.comp.emulators.qemu/229131. Rebasing > will fix the problem highlighted in the commit message of patch 2. > > Paolo Looks like all transitions from paused state should be allowed from panicked state. So why keep it separate?