From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:48927) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QmUYT-0006Ei-91 for qemu-devel@nongnu.org; Thu, 28 Jul 2011 13:39:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QmUYS-0005HZ-BH for qemu-devel@nongnu.org; Thu, 28 Jul 2011 13:39:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43057) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QmUYS-0005HG-36 for qemu-devel@nongnu.org; Thu, 28 Jul 2011 13:39:28 -0400 Date: Thu, 28 Jul 2011 14:39:23 -0300 From: Luiz Capitulino Message-ID: <20110728143923.3183d349@doriath> In-Reply-To: <4E317E49.5090708@web.de> References: <20110727154229.656532d4@doriath> <4E310E6A.6000004@redhat.com> <20110728103143.548d7bb1@doriath> <4E3165FD.7040805@redhat.com> <4E316FE7.6030005@web.de> <20110728121811.11dc8434@doriath> <4E317E49.5090708@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC] Introduce vm_stop_permanent() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Blue Swirl , Avi Kivity , qemu-devel On Thu, 28 Jul 2011 17:20:41 +0200 Jan Kiszka wrote: > On 2011-07-28 17:18, Luiz Capitulino wrote: > > On Thu, 28 Jul 2011 16:19:19 +0200 > > Jan Kiszka wrote: > > > >> On 2011-07-28 15:37, Avi Kivity wrote: > >>> On 07/28/2011 04:31 PM, Luiz Capitulino wrote: > >>>> On Thu, 28 Jul 2011 10:23:22 +0300 > >>>> Avi Kivity wrote: > >>>> > >>>>> On 07/28/2011 12:44 AM, Blue Swirl wrote: > >>>>> > On Wed, Jul 27, 2011 at 9:42 PM, Luiz > >>>> Capitulino wrote: > >>>>> > > This function should be used when the VM is not supposed to > >>>> resume > >>>>> > > execution (eg. by issuing 'cont' monitor command). > >>>>> > > > >>>>> > > Today, we allow the user to resume execution even when: > >>>>> > > > >>>>> > > o the guest shuts down and -no-shutdown is used > >>>>> > > o there's a kvm internal error > >>>>> > > o loading the VM state with -loadvm or "loadvm" in the > >>>> monitor fails > >>>>> > > > >>>>> > > I think only badness can happen from the cases above. > >>>>> > > >>>>> > I'd suppose a system_reset should bring the system back to > >>>> sanity and > >>>>> > then clear vm_permanent_stopped (where's -ly?) > >>>> > >>>> What's -ly? > >>>> > >>> > >>> permanent-ly. > >>> > >>>>> > except maybe for KVM > >>>>> > internal error if that can't be recovered. Then it would not very > >>>>> > permanent anymore, so the name would need adjusting. > >>>>> > >>>>> Currently, all kvm internal errors are recoverable by reset (and > >>>>> possibly by fiddling with memory/registers). > >>>> > >>>> Ok, but a poweroff in the guest isn't recoverable with system_reset > >>>> right? Or does it depend on the guest? > >>> > >>> Right, it's not recoverable if you shut the power down where the tractor > >>> beam is coupled to the main reactor. > >> > >> system_reset will bring all emulated devices back into their power-on > >> state - unless we have remaining bugs to fix. Actually, one may consider > >> issuing this reset automatically on vm_start after "permant" vm_stop. The only permanent vm_stop we'd have is poweroff when -no-shutdown is used. Are you saying that system_reset should be able to recover from that too? If yes, then I guess the right place is do_cont(). But I'm not sure we should do that (if -no-shutdown is not used, we'll exit() anyway). > > > > I'm going to abandon the vm_stop_permanent() idea. > > > > I'm thinking something towards having a stop_kind argument to vm_stop(), > > which could be temporary (which is what we have today), only with > > system_reset or permanent. > > > > Or maybe vm_stop_opt(), which allows for fine grained control of stop > > (vm_stop() would default to today's behavior)... > > But the right point for reset is start, not stop. Otherwise we loose the > state before the stop.