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Subject: Re: [Qemu-devel] [PATCH] qemu: Fix inject-nmi
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Lai Jiangshan <laijs@cn.fujitsu.com>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

On 09/25/2011 08:22 PM, Jan Kiszka wrote:
> On 2011-09-25 16:07, Avi Kivity wrote:
> >  On 09/23/2011 12:31 PM, Lai Jiangshan wrote:
> >>  >   Moreover: wrong indention.
> >>  >
> >>  >   You know that this won't work for qemu-kvm with in-kernel irqchip? You
> >>  >   may want to provide a patch for that tree, emulating the unavailable
> >>  >   LINT1 injection via testing the APIC configration and then raising an
> >>  >   NMI as before if it is accepted.
> >>  >
> >>
> >>  It works in my box but the NMI is not injected through the in-kernel
> >>  irqchip,
> >>  I will implement it as you suggested.
> >
> >  Somewhat hacky; isn't it better to test LINT1 in the kernel (and
> >  redefine the KVM_NMI ioctl as "toggle LINT1")?
>
> KVM_NMI is required for user space IRQ chip as well.

We could define KVM_NMI as edging the core NMI input if 
!irqchip_in_kernel, and toggling LINT1 otherwise.  Hardly nice though.

The current KVM_NMI with irqchip_in_kernel is not meaningful, since it 
doesn't obey the rules of any NMI source.

> Introducing some KVM_SET_LINT1 is an option though. But emulating it for
> the NMI button on older kernels sounds worthwhile nevertheless.
>

Perhaps this is the best option to avoid confusion.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.