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Date: Mon, 04 Apr 2011 08:05:48 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH 2/2 V7] qemu,qmp: add inject-nmi qmp command
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To: Avi Kivity <avi@redhat.com>
Cc: Lai Jiangshan <eag0628@gmail.com>, Lai Jiangshan <laijs@cn.fujitsu.com>, kvm@vger.kernel.org, Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org, Luiz Capitulino <lcapitulino@redhat.com>

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).

Regards,

Anthony Liguori