From mboxrd@z Thu Jan 1 00:00:00 1970 From: OGAWA Hirofumi Subject: Re: nmi is broken? Date: Thu, 28 Apr 2011 23:23:57 +0900 Message-ID: <87k4eeihdu.fsf@devron.myhome.or.jp> 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> Mime-Version: 1.0 Content-Type: text/plain Cc: Jan Kiszka , kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mail.parknet.co.jp ([210.171.160.6]:45746 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760506Ab1D1OYB (ORCPT ); Thu, 28 Apr 2011 10:24:01 -0400 In-Reply-To: <87sjt2ij8b.fsf@devron.myhome.or.jp> (OGAWA Hirofumi's message of "Thu, 28 Apr 2011 22:44:04 +0900") Sender: kvm-owner@vger.kernel.org List-ID: OGAWA Hirofumi writes: > Avi Kivity writes: > >>> This seems to be complex stuff depending on hardware configurations. I'm >>> not fully understanding though, current state of it is, >>> >>> Yes, PIC is in AEOI mode if linux is using IO-APIC. Um.., kvm says >>> irq == 0 is mp_INT mode in MADT, not mp_ExtINT. >> >> That is correct, kvm doesn't connect the master 8259 output to the >> IOAPIC. Instead the 8259 is connected to LINT0 (which is configured for >> ExtInt when the IOAPIC is disabled, or for NMI which the NMI watchdog is >> enabled). >> >> However, now I can't see how it would work. auto EOI works on the INTA >> cycle, which would only occur if LINT0 is configured for ExtInt. If it >> is configured for NMI, I don't think it would issue the INTA cycle. So >> the NMI watchdog not working is actually correct for our hardware >> configuration! >> >> But I may be misunderstanding something here. > > I see. If the physical machine was configured as above, I guess (not > pretty sure, I don't have this configuration machine), IOAPIC test > (check_timer() in io_apic.c) should fail, and IOAPIC wouldn't have any > effect. And I think MADT should tell mp_ExtINT. > > Yes, I also guess the above configuration wouldn't work NMI watchdog of > IOAPIC mode, and linux will report as NMI watchdog can't work in > check_timer(). Hm.., if smp was enabled, what configuration model is used by kvm? I think this configuration model can't work on smp. Thanks. -- OGAWA Hirofumi