From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] Re: [PATCH] Fix bug for vcpu hotplug Date: Thu, 19 Aug 2010 14:04:27 -0500 Message-ID: <4C6D803B.2000806@codemonkey.ws> References: <4C67D844.5060306@redhat.com> <4C6B8CC8.3040200@redhat.com> <4C6D4CA2.5060500@codemonkey.ws> <4C6D4F21.6070605@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Liu, Jinsong" , "Yang, Sheng" , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , "Li, Xin" To: Avi Kivity Return-path: Received: from mail-iw0-f174.google.com ([209.85.214.174]:63043 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752736Ab0HSTEc (ORCPT ); Thu, 19 Aug 2010 15:04:32 -0400 Received: by iwn1 with SMTP id 1so371881iwn.19 for ; Thu, 19 Aug 2010 12:04:32 -0700 (PDT) In-Reply-To: <4C6D4F21.6070605@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/19/2010 10:34 AM, Avi Kivity wrote: > On 08/19/2010 06:24 PM, Anthony Liguori wrote: >> On 08/18/2010 02:33 AM, Avi Kivity wrote: >>> On 08/18/2010 10:17 AM, Liu, Jinsong wrote: >>>> During test, we found qemu-kvm has a bug result in guestos shutdown >>>> when vcpu hotadd. >>>> This patch is to fix the bug, allow hotplug for sysbus qdev. >>>> >>>> --- a/hw/qdev.c >>>> +++ b/hw/qdev.c >>>> @@ -108,6 +108,7 @@ DeviceState *qdev_create(BusState *bus, const >>>> char *name) >>>> if (!bus) { >>>> if (!main_system_bus) { >>>> main_system_bus = qbus_create(&system_bus_info, NULL, >>>> "main-system-bus"); >>>> + main_system_bus->allow_hotplug = 1; >>>> } >>>> bus = main_system_bus; >>>> } >>> >>> >>> Looks reasonable to me. >> >> Not really to me. >> >> SysBus does not support hotplugging and CPU hot plug shouldn't have >> anything to do with qdev hotplug. >> >> Can you explain a bit more why this is needed? >> > > On cpu hotplug an apic is added, and apics live on main_system_bus. That's the problem then. An APIC does not live on any bus and that's where the problem ought to be fixed. Regards, Anthony Liguori