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	for speck@linutronix.de; Wed, 25 Apr 2018 20:11:56 +0200
Date: Wed, 25 Apr 2018 11:11:52 -0700
From: Andi Kleen <ak@linux.intel.com>
Subject: [MODERATED] Re: [PATCH 1/6] Patch 1
Message-ID: <20180425181152.GK14273@tassilo.jf.intel.com>
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To: speck@linutronix.de
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On Wed, Apr 25, 2018 at 11:00:57AM -0700, speck for Linus Torvalds wrote:
> 
> 
> On Wed, 25 Apr 2018, speck for Andi Kleen wrote:
> > 
> > If the MAX_PA-1 bit is inverted the address is not pointing to MMIO space anymore,
> > but likely to some real cached memory.
> 
> What the hell are you blathering about?
> 
> This is all only about the SWAP ENTRY. 

Ok. My patchkit handles both mprotect and swap entries. You're right 
we don't need it for swap entries and could use the inversion
there.

I was talking about mprotect though.

We need to handle mprotect (and potentially also non lazy fault mmap PROT_NONE)
because if we're in a guest setting something to PROT_NONE allows to bypass EPT temporarily, so you could suddenly see the values of some other guest pages.

What's your opinion on that case?

-Andi