From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 1/1 V5] kernel/kvm: introduce KVM_SET_LINT1 and fix improper nmi emulation Date: Mon, 17 Oct 2011 12:21:21 +0200 Message-ID: <4E9C01A1.3090709@siemens.com> References: <20110913093835.GB4265@localhost.localdomain> <20110914093441.e2bb305c.kamezawa.hiroyu@jp.fujitsu.com> <4E705BC3.5000508@cn.fujitsu.com> <20110915164704.9cacd407.kamezawa.hiroyu@jp.fujitsu.com> <4E71B28F.7030201@cn.fujitsu.com> <4E72F3BA.2000603@jp.fujitsu.com> <4E73200A.7040908@jp.fujitsu.com> <4E76C6AA.9080403@cn.fujitsu.com> <4E7B04DC.1030407@cn.fujitsu.com> <4E7B4B8F.507@siemens.com> <4E7C51E4.2000503@cn.fujitsu.com> <4E7F3585.40108@redhat.com> <4E7F635E.6080009@web.de> <4E8035F9.9080908@redhat.com> <4E928B54.1070707@cn.fujitsu.com> <4E92958E.9000509@web.de> <4E9476E2.1070804@cn.fujitsu.com> <4E948842.4030406@web.de> <4E978827.6070008@cn.fujitsu.com> <4E97CE42.9020102@web.de> <4E97D85C.7070107@cn.fujitsu.com> <4E97DB62.9020605@web.de> <4E97FAC7.6080007@cn.fujitsu.com> <4E9A A657.1050503@redhat.com> <4E9BF2A0.40306@cn.fujitsu.com> <4E9BFB3D.5030704@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Lai Jiangshan , Kenji Kaneshige , KAMEZAWA Hiroyuki , "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" To: Avi Kivity Return-path: Received: from goliath.siemens.de ([192.35.17.28]:22457 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750946Ab1JQKVv (ORCPT ); Mon, 17 Oct 2011 06:21:51 -0400 In-Reply-To: <4E9BFB3D.5030704@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2011-10-17 11:54, Avi Kivity wrote: > On 10/17/2011 11:17 AM, Lai Jiangshan wrote: >> On 10/16/2011 05:39 PM, Avi Kivity wrote: >>> On 10/14/2011 11:03 AM, Lai Jiangshan wrote: >>>> Currently, NMI interrupt is blindly sent to all the vCPUs when NMI >>>> button event happens. This doesn't properly emulate real hardware on >>>> which NMI button event triggers LINT1. Because of this, NMI is sent to >>>> the processor even when LINT1 is masked in LVT. For example, this >>>> causes the problem that kdump initiated by NMI sometimes doesn't work >>>> on KVM, because kdump assumes NMI is masked on CPUs other than CPU0. >>>> >>>> With this patch, we introduce introduce KVM_SET_LINT1, >>>> and we can use KVM_SET_LINT1 to correctly emulate NMI button >>>> without change the old KVM_NMI behavior. >>>> >>>> @@ -759,6 +762,8 @@ struct kvm_clock_data { >>>> #define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce) >>>> /* Available with KVM_CAP_RMA */ >>>> #define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma) >>>> +/* Available with KVM_CAP_SET_LINT1 for x86 */ >>>> +#define KVM_SET_LINT1 _IO(KVMIO, 0xaa) >>>> >>>> >>> >>> LINT1 may have been programmed as a level -triggered interrupt instead >>> of edge triggered (NMI or interrupt). We can use the ioctl argument for >>> the level (and pressing the NMI button needs to pulse the level to 1 and >>> back to 0). >>> >> >> Hi, Avi, >> >> How to handle level=0 in the kernel? >> Or just ignore it? > > It needs to be handled according to the delivery mode, polarity, and > trigger mode bits in the LVT. > > For example, a Fixed delivery mode with polarity 1 and level trigger > mode will post the interrupt as long as it is in level 0 and not masked > by the ISR. __apic_accept_irq() should handle this. But I think it's not yet fully prepared for this (level is only considered for APIC_DM_INIT e.g.). Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:33974) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RFkKN-0003Jj-NM for qemu-devel@nongnu.org; Mon, 17 Oct 2011 06:21:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RFkKJ-00074e-Jy for qemu-devel@nongnu.org; Mon, 17 Oct 2011 06:21:51 -0400 Received: from goliath.siemens.de ([192.35.17.28]:33848) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RFkKJ-00074R-8u for qemu-devel@nongnu.org; Mon, 17 Oct 2011 06:21:47 -0400 Message-ID: <4E9C01A1.3090709@siemens.com> Date: Mon, 17 Oct 2011 12:21:21 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <20110913093835.GB4265@localhost.localdomain> <20110914093441.e2bb305c.kamezawa.hiroyu@jp.fujitsu.com> <4E705BC3.5000508@cn.fujitsu.com> <20110915164704.9cacd407.kamezawa.hiroyu@jp.fujitsu.com> <4E71B28F.7030201@cn.fujitsu.com> <4E72F3BA.2000603@jp.fujitsu.com> <4E73200A.7040908@jp.fujitsu.com> <4E76C6AA.9080403@cn.fujitsu.com> <4E7B04DC.1030407@cn.fujitsu.com> <4E7B4B8F.507@siemens.com> <4E7C51E4.2000503@cn.fujitsu.com> <4E7F3585.40108@redhat.com> <4E7F635E.6080009@web.de> <4E8035F9.9080908@redhat.com> <4E928B54.1070707@cn.fujitsu.com> <4E92958E.9000509@web.de> <4E9476E2.1070804@cn.fujitsu.com> <4E948842.4030406@web.de> <4E978827.6070008@cn.fujitsu.com> <4E97CE42.9020102@web.de> <4E97D85C.7070107@cn.fujitsu.com> <4E97DB62.9020605@web.de> <4E97FAC7.6080007@cn.fujitsu.com> <4E9AA657.1050503@redhat.com> <4E9BF2A0.40306@cn.fujitsu.com> <4E9BFB3D.5030704@redhat.com> In-Reply-To: <4E9BFB3D.5030704@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/1 V5] kernel/kvm: introduce KVM_SET_LINT1 and fix improper nmi emulation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , Lai Jiangshan , KAMEZAWA Hiroyuki , Kenji Kaneshige On 2011-10-17 11:54, Avi Kivity wrote: > On 10/17/2011 11:17 AM, Lai Jiangshan wrote: >> On 10/16/2011 05:39 PM, Avi Kivity wrote: >>> On 10/14/2011 11:03 AM, Lai Jiangshan wrote: >>>> Currently, NMI interrupt is blindly sent to all the vCPUs when NMI >>>> button event happens. This doesn't properly emulate real hardware on >>>> which NMI button event triggers LINT1. Because of this, NMI is sent to >>>> the processor even when LINT1 is masked in LVT. For example, this >>>> causes the problem that kdump initiated by NMI sometimes doesn't work >>>> on KVM, because kdump assumes NMI is masked on CPUs other than CPU0. >>>> >>>> With this patch, we introduce introduce KVM_SET_LINT1, >>>> and we can use KVM_SET_LINT1 to correctly emulate NMI button >>>> without change the old KVM_NMI behavior. >>>> >>>> @@ -759,6 +762,8 @@ struct kvm_clock_data { >>>> #define KVM_CREATE_SPAPR_TCE _IOW(KVMIO, 0xa8, struct kvm_create_spapr_tce) >>>> /* Available with KVM_CAP_RMA */ >>>> #define KVM_ALLOCATE_RMA _IOR(KVMIO, 0xa9, struct kvm_allocate_rma) >>>> +/* Available with KVM_CAP_SET_LINT1 for x86 */ >>>> +#define KVM_SET_LINT1 _IO(KVMIO, 0xaa) >>>> >>>> >>> >>> LINT1 may have been programmed as a level -triggered interrupt instead >>> of edge triggered (NMI or interrupt). We can use the ioctl argument for >>> the level (and pressing the NMI button needs to pulse the level to 1 and >>> back to 0). >>> >> >> Hi, Avi, >> >> How to handle level=0 in the kernel? >> Or just ignore it? > > It needs to be handled according to the delivery mode, polarity, and > trigger mode bits in the LVT. > > For example, a Fixed delivery mode with polarity 1 and level trigger > mode will post the interrupt as long as it is in level 0 and not masked > by the ISR. __apic_accept_irq() should handle this. But I think it's not yet fully prepared for this (level is only considered for APIC_DM_INIT e.g.). Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux