From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amit Shah Subject: Re: [PATCH 1/1] kvmclock: fix guest stop notification Date: Mon, 8 Oct 2012 16:13:34 +0530 Message-ID: <20121008104334.GD25290@amit.redhat.com> References: <20120930230516.GA3923@amt.cnet> <1389829631.4053667.1349056207458.JavaMail.root@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Marcelo Tosatti , qemu list , kvm list , Eric B Munson , Raghavendra K T , Andreas =?iso-8859-1?Q?F=E4rber?= , Paolo Bonzini , Laszlo Ersek To: Amos Kong Return-path: Received: from mx1.redhat.com ([209.132.183.28]:39275 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750833Ab2JHKns (ORCPT ); Mon, 8 Oct 2012 06:43:48 -0400 Content-Disposition: inline In-Reply-To: <1389829631.4053667.1349056207458.JavaMail.root@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On (Sun) 30 Sep 2012 [21:50:07], Amos Kong wrote: > ----- Original Message ----- > > On Thu, Sep 20, 2012 at 09:46:41AM -0300, Marcelo Tosatti wrote: > > > On Thu, Sep 20, 2012 at 01:55:20PM +0530, Amit Shah wrote: > > > > Commit f349c12c0434e29c79ecde89029320c4002f7253 added the guest > > > > stop > > In commitlog of f349c12c0434e29c79ecde89029320c4002f7253: > > ## This patch uses the qemu Notifier system to tell the guest it _is about to be_ stopped > > > > > > notification, but it did it in a way that the stop notification > > > > would > > > > never reach the kernel. The kvm_vm_state_changed() function gets > > > > a > > > > value of 0 for the 'running' parameter when the VM is stopped, > > > > making > > > > all the code added previously dead code. > > > > > > > > This patch reworks the code so that it's called when 'running' is > > > > 0, > > > > which indicates the VM was stopped. > > Amit, did you touch any real issue? guest gets call trace with current code? > which kind of context? I guess you're asking for a testcase to trigger softlockups? Run a VM, make it do some work (like kernel compile). Then, 'stop' from the monitor for a few minutes. Later, on 'cont', the softlockup detector in the guest wakes up and shows a warning message mentioning the cpus were stuck for seconds. For this particular patch, though, I didn't really test things; just 'found' this by examining code. But as Marcelo points out, this patch is wrong. > Someone told me he got call trace when shutdown guest by 'init 0', I didn't > verify this issue. That sounds like a completely different thing, unless the trace is invoked by the softlockup detector. Amit