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Date: Tue, 8 Nov 2016 14:16:00 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
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Subject: Re: [PATCH 0/4] x86: enable User-Mode Instruction Prevention
Message-ID: <20161108131600.GF3117@twins.programming.kicks-ass.net>
References: <1478585533-19406-1-git-send-email-ricardo.neri-calderon@linux.intel.com>
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On Mon, Nov 07, 2016 at 10:12:09PM -0800, Ricardo Neri wrote:
> There is a caveat, however. Certain applications running in virtual-8086
> mode, such as DOSEMU[1] and Wine[2], want to utilize the SGDT, SIDT and
> SLDT instructions for legitimate reasons. In order to keep such
> applications working, UMIP must be disabled/enabled when entering/exiting
> virtual-8086 mode. 

Would it not be better to emulate these instructions for them? What way
we can verify they're not malicious.