From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35669) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ws7eW-00089m-S7 for qemu-devel@nongnu.org; Wed, 04 Jun 2014 05:38:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ws7eQ-00008s-JY for qemu-devel@nongnu.org; Wed, 04 Jun 2014 05:38:36 -0400 Message-ID: <538EE913.6090609@suse.de> Date: Wed, 04 Jun 2014 11:38:27 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1401869330-32449-1-git-send-email-aik@ozlabs.ru> <538EE73D.4080408@ozlabs.ru> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 0/4] cpus: Add generic NMI support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , Alexey Kardashevskiy Cc: Alex Bligh , Markus Armbruster , QEMU Developers , Luiz Capitulino , "qemu-ppc@nongnu.org" , Stefan Hajnoczi , Cornelia Huck , Paolo Bonzini , =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= , Richard Henderson On 04.06.14 11:33, Peter Maydell wrote: > On 4 June 2014 10:30, Alexey Kardashevskiy wrote: >> On 06/04/2014 07:16 PM, Peter Maydell wrote: >>> On 4 June 2014 09:08, Alexey Kardashevskiy wrote: >>>> This adds an NMI handler per CPUs. x86, s390 and ppc CPUS are supported. >>>> >>>> The change to existing behaviour is that x86 only delivers NMI to >>>> the current monitored CPU now, not to every CPU. >>> So this series means that the "nmi" command and handler does >>> * NMI on x86 >>> * reset on PPC >> The vector is called "reset" but it is an interrupt, and I do not see any >> way to mask it. >> >>> * restart on S390 >> The vector is called "restart" but it is still an interrupt. > So? ARM has an interrupt called "NMI" but there's zero reason > you'd want to poke it from the monitor, any more than you'd > want to try to hand-send any other kind of interrupt. > >>> That doesn't seem generic at all, and suggests this should >>> not be a common CPU method/callback. >> Oh. Ok. Suggestions? > I dunno. What are you actually trying to achieve? Linux configures certain interrupts to trigger an emergency situation - usually to get you into a debugger or to start a crash kexec kernel. The command is called "nmi" because it originally was used on x86 to do this and there the NMI interrupt is the one Linux uses for that purpose. In fact, on x86 bringup systems you often have an "NMI" button next to the "reset" and "power on" buttons. Alex