From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex =?utf-8?Q?Benn=C3=A9e?= Subject: Re: [PATCH 2/2] KVM: Create debugfs dir and stat files for each VM Date: Mon, 30 Nov 2015 15:10:53 +0000 Message-ID: <87a8pvbk02.fsf@linaro.org> References: <56576FD6.40506@de.ibm.com> <56581A59.4080705@de.ibm.com> <565C0ACA.9080204@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Tyler Baker , Christian Borntraeger , kvm@vger.kernel.org, pbonzini@redhat.com, pmorel@linux.vnet.ibm.com, dan.carpenter@oracle.com, Kevin's boot bot To: Janosch Frank Return-path: Received: from mail-wm0-f48.google.com ([74.125.82.48]:37202 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754209AbbK3PLB (ORCPT ); Mon, 30 Nov 2015 10:11:01 -0500 Received: by wmww144 with SMTP id w144so141648735wmw.0 for ; Mon, 30 Nov 2015 07:10:59 -0800 (PST) In-reply-to: <565C0ACA.9080204@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: Janosch Frank writes: > On 11/27/2015 09:42 PM, Tyler Baker wrote: >> On 27 November 2015 at 10:53, Tyler Baker w= rote: >>> On 27 November 2015 at 09:08, Tyler Baker = wrote: >>>> On 27 November 2015 at 00:54, Christian Borntraeger >>>> wrote: >>>>> On 11/26/2015 09:47 PM, Christian Borntraeger wrote: >>>>>> On 11/26/2015 05:17 PM, Tyler Baker wrote: >>>>>>> Hi Christian, >>>>>>> >>>>>>> The kernelci.org bot recently has been reporting kvm guest boot >>>>>>> failures[1] on various arm64 platforms in next-20151126. The bo= t >>>>>>> bisected[2] the failures to the commit in -next titled "KVM: Cr= eate >>>>>>> debugfs dir and stat files for each VM". I confirmed by reverti= ng this >>>>>>> commit on top of next-20151126 it resolves the boot issue. >>>>>>> >> > After a quick look into qemu I guess I've found the problem: > kvm_init creates a vm, does checking and self initialization and > then calls kvm_arch_init. The arch initialization indirectly > calls kvm_arm_create_scratch_host_vcpu and that's where the > trouble begins, as it also creates a VM. > > My assumption was, that nobody would create multiple VMs under > the same PID. Christian and I are working on a solution on kernel > side. Yeah ARM is a little weird in that respect as the scratch VM is used to probe capabilities. There is nothing in the API that says you can't hav= e multiple VMs per PID so I guess a better unique identifier is needed. -- Alex Benn=C3=A9e