From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40038) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fixx6-0006Rr-NV for qemu-devel@nongnu.org; Fri, 27 Jul 2018 04:18:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fixx3-0002wQ-JB for qemu-devel@nongnu.org; Fri, 27 Jul 2018 04:18:20 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56740 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fixx3-0002wI-BX for qemu-devel@nongnu.org; Fri, 27 Jul 2018 04:18:17 -0400 Reply-To: thuth@redhat.com References: <153252992640.319494.8451297710133862507.stgit@bahia.lan> <20180727052724.GJ3694@umbus.fritz.box> <20180727095452.45edee8b@bahia> From: Thomas Huth Message-ID: Date: Fri, 27 Jul 2018 10:18:14 +0200 MIME-Version: 1.0 In-Reply-To: <20180727095452.45edee8b@bahia> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-3.1] tests/cpu-plug-test: check CPU hotplug on ppc64 with KVM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz , David Gibson Cc: qemu-devel@nongnu.org, =?UTF-8?Q?C=c3=a9dric_Le_Goater?= On 07/27/2018 09:54 AM, Greg Kurz wrote: > On Fri, 27 Jul 2018 15:27:24 +1000 > David Gibson wrote: > >> On Wed, Jul 25, 2018 at 04:45:26PM +0200, Greg Kurz wrote: >>> Commit b585395b655 fixed a regression introduced by some recent changes >>> in the XICS code, that was causing QEMU to crash instantly during CPU >>> hotplug with KVM. This is typically the kind of bug we'd like our >>> test suite to detect before it gets merged. Unfortunately, the current >>> tests run with '-machine accel=qtest' and don't exercise KVM specific >>> paths in QEMU. >>> >>> This patch hence changes add_pseries_test_case() to launch QEMU with >>> '-machine accel=kvm' if KVM is available. >>> >>> A notable consequence is that the guest will execute SLOF, but for some >>> reasons SLOF sometimes hits a program exception. This causes the guest >>> to loop forever and the test to be stuck. Since we don't need the guest >>> to be truely running, let's pass -S to QEMU to avoid that. >>> >>> Also disable machine capabilities that could be unavailable in KVM, eg, >>> when using PR KVM. >>> >>> Signed-off-by: Greg Kurz >> >> I'm pretty sure trying to change the accelerator on a qtest test just >> doesn't make sense. We'd need a different approach for testing cpu >> hotplug against kvm & tcg backends. >> > > The test starts QEMU, triggers the CPU hotplug code with a QMP command > and checks the command didn't fail (or QEMU didn't crash, as it would > have before commit b585395b655a)... I really don't understand what > is wrong with that... Please elaborate. For a "real" test, I think you'd need a guest OS that is reacting to the hot plug events. So maybe this should rather be done in the avocado framework instead? Thomas