From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [Qemu-devel] [PATCH 2/2 V7] qemu,qmp: add inject-nmi qmp command Date: Wed, 06 Apr 2011 20:17:47 +0200 Message-ID: <4D9CAE4B.7080305@siemens.com> References: <4D74A8C9.2020408@cn.fujitsu.com> <4D74A974.6090509@cn.fujitsu.com> <20110404105949.GA30324@redhat.com> <4D99BF99.1040305@redhat.com> <4D99C22C.4070401@codemonkey.ws> <20110406144723.45333682@doriath> <4D9CAAF9.7000509@codemonkey.ws> <20110406150818.56707b9b@doriath> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , Lai Jiangshan , Jiangshan , kvm@vger.kernel.org, Markus Armbruster , qemu-devel@nongnu.org, Avi Kivity To: Luiz Capitulino Return-path: Received: from david.siemens.de ([192.35.17.14]:26841 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755350Ab1DFSSG (ORCPT ); Wed, 6 Apr 2011 14:18:06 -0400 In-Reply-To: <20110406150818.56707b9b@doriath> Sender: kvm-owner@vger.kernel.org List-ID: On 2011-04-06 20:08, Luiz Capitulino wrote: > On Wed, 06 Apr 2011 13:03:37 -0500 > Anthony Liguori wrote: > >> On 04/06/2011 12:47 PM, Luiz Capitulino wrote: >>> On Mon, 04 Apr 2011 08:05:48 -0500 >>> Anthony Liguori wrote: >>> >>>> On 04/04/2011 07:54 AM, Avi Kivity wrote: >>>>> On 04/04/2011 01:59 PM, Daniel P. Berrange wrote: >>>>>> Interesting that with HMP you need to specify a single CPU index, but >>>>>> with QMP it is injecting to all CPUs at once. Is there any compelling >>>>>> reason why we'd ever need the ability to only inject to a single CPU >>>>>> from an app developer POV ? >>>>> When a PC has an NMI button, it is (I presume) connected to all CPUs' >>>>> LINT1 pin, which is often configured as an NMI input. So the all-cpu >>>>> variant corresponds to real hardware, while the single-cpu variant >>>>> doesn't. >>>>> >>>>> wrt the app developer POV, the only use I'm aware of is that you can >>>>> configure Windows to dump core when the NMI button is pressed and thus >>>>> debug driver problems. It's likely more reliable when sent to all cpus. >>>> It either needs to be removed from HMP or added to QMP. HMP shouldn't >>>> have more features than QMP (even if those features are non-sensible). >>> Is anyone against changing HMP behavior to send it to all CPUs? >> >> Makes sense to me. > > So, Lai, in order to get this merged could you please do the following: > > 1. Address checkpath.pl errors > > 2. Change the HMP to use this implementation, which send the NMI > to all CPUs HMP is currently x86-only, thus it's probably OK to model it after some PC feature (though I don't know if there aren't NMI buttons with BP-only wirings). But will the consolidate version be defined for all architectures? We should avoid "exporting" x86-specific assumptions. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux