From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48379) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8uxU-0003lN-5Q for qemu-devel@nongnu.org; Mon, 12 Aug 2013 12:27:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V8uxO-0002Bh-5Q for qemu-devel@nongnu.org; Mon, 12 Aug 2013 12:27:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34227) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8uxN-0002Au-TJ for qemu-devel@nongnu.org; Mon, 12 Aug 2013 12:26:58 -0400 Message-ID: <1376324800.10576.3.camel@localhost.localdomain> From: Marcel Apfelbaum Date: Mon, 12 Aug 2013 19:26:40 +0300 In-Reply-To: <52090505.1010802@redhat.com> References: <1376233843-19410-1-git-send-email-marcel.a@redhat.com> <52090505.1010802@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-1.6 V2 0/2] pvpanic: Separate pvpanic from machine type List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: aliguori@us.ibm.com, gleb@redhat.com, mst@redhat.com, hutao@cn.fujitsu.com, qemu-devel@nongnu.org, vrozenfe@redhat.com, pbonzini@redhat.com, afaerber@suse.de, kraxel@redhat.com On Mon, 2013-08-12 at 09:53 -0600, Eric Blake wrote: > On 08/11/2013 09:10 AM, Marcel Apfelbaum wrote: > > Creating the pvpanic device as part of the machine type has the > > potential to trigger guest OS, guest firmware and driver bugs. > > The potential of such was originally viewed as minimal. > > However, since releasing 1.5 with pvpanic as part > > of the builtin machine type, several issues were observed > > in the field: > > - Some Windows versions triggered 'New Hardware Wizard' and > > an unidentified device appeared in Device Manager. > > - Issue reported off list: on Linux >= 3.10 > > the pvpanic driver breaks the reset on crash option: > > VM stops instead of being reset. > > > > pvpanic device also changes monitor command behaviour in some cases, > > such silent incompatible changes aren't expected by management tools: > > - Monitor command requires 'cont' before 'system_reset' > > in order to restart the VM after kernel panic/BSOD > > > > Note that libvirt is the main user and libvirt people indicated their > > preference to creating device with -device pvpanic rather than a > > built-in one that can't be removed. > > > > These issues were raised at last KVM call. The agreement reached > > there was that we were a bit too rash to make the device > > a builtin, and that for 1.6 we should drop the pvpanic device from the > > default machine type, instead teach management tools to add it by > > default using -device pvpanic. > > It's not clear whether changing 1.5 behaviour at this point > > is a sane thing, so this patchset doesn't touch 1.5 machine type. > > Thanks for doing this; it makes sense to get this in for 1.6. From the > libvirt point of view: Eric, my pleasure! And I really think that using "-device pvpanic" is the right thing to to do. Marcel > > Series: Reviewed-by: Eric Blake >