From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH] KVM: VMX: Translate interrupt shadow when waiting on
 NMI window
Date: Tue, 16 Feb 2010 12:06:35 +0200
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Cc: Avi Kivity <avi@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>,
	kvm <kvm@vger.kernel.org>
To: Jan Kiszka <jan.kiszka@siemens.com>
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On Tue, Feb 16, 2010 at 11:04:10AM +0100, Jan Kiszka wrote:
> Gleb Natapov wrote:
> > On Tue, Feb 16, 2010 at 10:16:12AM +0100, Jan Kiszka wrote:
> >> Found while browsing Xen code: While we assume that the STI interrupt
> >> shadow also inplies virtual NMI blocking, some processors may have a
> >> different opinion (SDM 3: 22.3). To avoid misunderstandings that would
> >> cause endless VM entry attempts, translate STI into MOV SS blocking when
> >> requesting the NMI window.
> >>
> > Why not just remove "block by STI" check in vmx_nmi_allowed()? IIRC this
> > is documented that on some CPUs STI does not block NMI.
> > 
> 
> Probably because we will stumble and fall on those CPUs that do care.
> 
But this defines behaviour of cpu _we_ emulate. So on _our_ cpu NMI will
not be blocked by STI.

--
			Gleb.