From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:35128) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QmUhJ-0001Xf-TA for qemu-devel@nongnu.org; Thu, 28 Jul 2011 13:48:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QmUhH-00076F-UT for qemu-devel@nongnu.org; Thu, 28 Jul 2011 13:48:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7764) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QmUhH-00075v-Jw for qemu-devel@nongnu.org; Thu, 28 Jul 2011 13:48:35 -0400 Date: Thu, 28 Jul 2011 14:48:31 -0300 From: Luiz Capitulino Message-ID: <20110728144831.766fa270@doriath> In-Reply-To: <20110728143923.3183d349@doriath> 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> <20110728143923.3183d349@doriath> 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 14:39:23 -0300 Luiz Capitulino wrote: > 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? It already does, so we don't have permanent stops. > > 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. >