From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55590) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9Amh-0002Nr-PA for qemu-devel@nongnu.org; Wed, 16 Dec 2015 07:02:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a9Amd-000238-NR for qemu-devel@nongnu.org; Wed, 16 Dec 2015 07:02:19 -0500 Received: from mail-wm0-x233.google.com ([2a00:1450:400c:c09::233]:36475) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a9Amd-00022E-IA for qemu-devel@nongnu.org; Wed, 16 Dec 2015 07:02:15 -0500 Received: by mail-wm0-x233.google.com with SMTP id n186so206743407wmn.1 for ; Wed, 16 Dec 2015 04:02:15 -0800 (PST) Sender: Paolo Bonzini References: <1450256449-23779-1-git-send-email-den@openvz.org> <56712AF4.9030105@redhat.com> <20151216095029.GW1404639@andariel.pipo.sk> From: Paolo Bonzini Message-ID: <567152C4.1010004@redhat.com> Date: Wed, 16 Dec 2015 13:02:12 +0100 MIME-Version: 1.0 In-Reply-To: <20151216095029.GW1404639@andariel.pipo.sk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH 1/1] qmp: process system-reset event in paused state List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Krempa Cc: "Denis V. Lunev" , qemu-devel@nongnu.org, Dmitry Andreev , Markus Armbruster On 16/12/2015 10:50, Peter Krempa wrote: > We check that the state is "paused" and continue the vCPUs only in > that case. The panic devices will move the VM to 'crashed' state. > The code that is issuing 'system_reset' does not modify the state > in any way. Ok, thanks. > I'd say NACK here. This will break the possibility to reset a > system while the vCPUs are paused. The problem should be fixed in > libvirt. It is indeed a QEMU bug, and it was introduced in commit df39076 ("vl: allow "cont" from panicked state", 2013-11-04). Until that commit, a system_reset in panicked state would change the status to paused. The commit changed that as a side effect of removing VM_STATE_GUEST_PANICKED from runstate_needs_reset; see the call to runstate_needs_reset in main_loop_should_exit. IMO, after a reset, main_loop_should_exit should actually transition to VM_STATE_PRELAUNCH (*not* RUN_STATE_PAUSED) for *all* states except RUN_STATE_INMIGRATE, RUN_STATE_SAVE_VM (which I think cannot happen there) and (of course) RUN_STATE_RUNNING. Some changes will be required to the transition table as well. This will fix similar bugs for other runstates as well, though most of them probably cannot be triggered from libvirt. Thanks, Paolo