From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: nmi is broken? Date: Tue, 03 May 2011 16:35:50 +0300 Message-ID: <4DC004B6.3030503@redhat.com> References: <87sjtbe7fz.fsf@devron.myhome.or.jp> <877hak1t1s.fsf@devron.myhome.or.jp> <4DB3C6D3.9040703@redhat.com> <4DB41696.6060606@web.de> <4DB7DA11.8040503@redhat.com> <871v0njhab.fsf@devron.myhome.or.jp> <4DB93A6D.3010703@redhat.com> <87sjt2ij8b.fsf@devron.myhome.or.jp> <87k4eeihdu.fsf@devron.myhome.or.jp> <87mxj7urb0.fsf@devron.myhome.or.jp> <4DBE6F6B.6090103@redhat.com> <8739kxgoo0.fsf@devron.myhome.or.jp> <4DBFCC81.9080401@redhat.com> <4DBFD3F5.8020406@redhat.com> <87hb9blxvt.fsf@devron.myhome.or.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jan Kiszka , kvm@vger.kernel.org To: OGAWA Hirofumi Return-path: Received: from mx1.redhat.com ([209.132.183.28]:22710 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751910Ab1ECNfz (ORCPT ); Tue, 3 May 2011 09:35:55 -0400 In-Reply-To: <87hb9blxvt.fsf@devron.myhome.or.jp> Sender: kvm-owner@vger.kernel.org List-ID: On 05/03/2011 04:25 PM, OGAWA Hirofumi wrote: > Avi Kivity writes: > > > On 05/03/2011 12:36 PM, Avi Kivity wrote: > >> > >>> I don't know about live migration of kvm. If we said the wiring is like > >>> figure 5-2, what is required for the live migration? It was required > >>> only if IMCR was required? > >> > >> The issue with live migration is that we can't change the running > >> configuration while the system is running, like adding the IMCR or > >> changing the wiring. The hardware will be programmed for the old > >> configuration and will likely fail with the new one. For example, the > >> current wiring has the PIT output wired to PIC IRQ0 and IOAPIC INTI0; > >> we need to change it to IOAPIC INTI2 instead. > >> > > > > btw, I believe that the configuration currently implemented is legal > > (it's similar to config 7 in table 5-2 of the mpspec); the only problem > > is that it can't support the NMI watchdog through the I/O APIC trick, > > yet we allow it through a hack. > > I'm confused a bit. "config 7 in table 5-2" says PIT output wired to > IOAPIC INTIN2. So, we don't need to change it? We're like config 7 in that the 8259A output isn't wired to the IOAPIC. However we're unlike config 7 in that the PIT output is wired to IOAPIC INTIN0. I think we can keep it that way. > > Something we can do is connect the 8259A output to the I/O APIC INTIN2; > > it should be masked so live migration will continue to work. We just > > have to make sure that the guest is able to find that it is connected there. > > 8259A INTR to IOAPIC INTIN2 sounds strange. Isn't it IOAPIC INTIN0? Usually yes, but we already have the PIT wired to INTIN0. I saw that the kernel consults the mptable to see which pin to use, so with the right BIOS magic we can get things to work. -- error compiling committee.c: too many arguments to function