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Subject: Re: [PATCH 6/6] x86: Fix stray A/D bit setting into non-present PTEs
To: Brian Gerst <brgerst@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
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On 06/30/2016 08:06 PM, Brian Gerst wrote:
>> > It's not like anybody will ever care about 32-bit page tables on
>> > Knights Landing anyway.
> Could this affect a 32-bit guest VM?

This isn't about 32-bit *mode*.  It's about using the the 32-bit 2-level
_paging_ mode that supports only 4GB virtual and 4GB physical addresses.
 That mode also doesn't support the No-eXecute (NX) bit, which basically
everyone needs today for its security benefits.

Even the little Quark CPU supports PAE (64-bit page tables).