linux-kernel - Re: [PATCH v2 00/13] SMM implementation for KVM

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Date:	Fri, 29 May 2015 21:34:00 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Radim Krčmář <rkrcmar@...hat.com>
CC:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	guangrong.xiao@...ux.intel.com, bdas@...hat.com
Subject: Re: [PATCH v2 00/13] SMM implementation for KVM



On 29/05/2015 21:03, Radim Krčmář wrote:
> I found a corner case that doesn't fit any specific patch:
> 
> We allow INIT while in SMM.  This brings some security complications as
> we also don't reset hflags (another long standing bug?), but we don't
> really need to because INIT in SMM is against the spec anyway;
> APM May 2013 2:10.3.3 Exceptions and Interrupts,
>   • INIT—The processor does not recognize INIT while in SMM.
> 
> SDM April 2015: 34.5.1  Initial SMM Execution Environment,
>   Maskable hardware interrupts, exceptions, NMI interrupts, SMI
>   interrupts, A20M interrupts, single-step traps, breakpoint traps, and
>   INIT operations are inhibited when the processor enters SMM.
> 
> And there is no mention of an exception for INIT.
> (Some extra old experiments say that INIT could be enabled, but that is
>  not applicable now,  http://www.rcollins.org/ddj/Mar97/Mar97.html)
> 
> I think that INIT received before RSM should be delivered after.

Yes.  I'll look at it next week and post a 14th patch.

Paolo
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