From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48707) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8XIp-0005yq-Ao for qemu-devel@nongnu.org; Sun, 11 Aug 2013 11:11:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V8XIk-0001C8-6D for qemu-devel@nongnu.org; Sun, 11 Aug 2013 11:11:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15293) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V8XIj-0001C2-TC for qemu-devel@nongnu.org; Sun, 11 Aug 2013 11:11:26 -0400 From: Marcel Apfelbaum Date: Sun, 11 Aug 2013 18:10:41 +0300 Message-Id: <1376233843-19410-1-git-send-email-marcel.a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [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: qemu-devel@nongnu.org Cc: aliguori@us.ibm.com, gleb@redhat.com, mst@redhat.com, hutao@cn.fujitsu.com, Marcel Apfelbaum , kraxel@redhat.com, pbonzini@redhat.com, afaerber@suse.de, vrozenfe@redhat.com 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 >=3D 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=20 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. This patch series reworks the patchset from Hu Tao (don't create pvpanic device by default) addressing comments and modifying behaviour according to what was discussed on the call. Please review and consider for 1.6. A related discussion can be followed at=20 http://lists.nongnu.org/archive/html/qemu-devel/2013-08/msg00036.html.=20 This is a continuation of patches sent by Hu Tao: http://lists.nongnu.org/archive/html/qemu-devel/2013-08/msg00124.html http://lists.nongnu.org/archive/html/qemu-devel/2013-08/msg00125.html Changes from v1 (by Hu Tao): - Keep pvpanic device enabled by default for 1.5 for backport compatibility - Addressed Andreas F=C3=A4rber review (removed bus type) - Small changes to be posible to enable pvpanic both from command line and from machine_init - Added pvpanic to MISC category Marcel Apfelbaum (2): hw/misc: don't create pvpanic device by default hw/misc: make pvpanic known to user hw/i386/pc_piix.c | 9 ++++----- hw/i386/pc_q35.c | 7 ++++--- hw/misc/pvpanic.c | 25 ++++++++++--------------- 3 files changed, 18 insertions(+), 23 deletions(-) --=20 1.8.3.1