From: Kees Cook <keescook@google.com>
To: "Woodhouse, David" <dwmw@amazon.co.uk>
Cc: "torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"konrad.wilk@oracle.com" <konrad.wilk@oracle.com>,
"juerg.haefliger@hpe.com" <juerg.haefliger@hpe.com>,
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"boris.ostrovsky@oracle.com" <boris.ostrovsky@oracle.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
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Subject: Re: Redoing eXclusive Page Frame Ownership (XPFO) with isolated CPUs in mind (for KVM to isolate its guests per CPU)
Date: Mon, 20 Aug 2018 15:18:20 -0700 [thread overview]
Message-ID: <CAGXu5jLSPGe7W0qpUYoQr4C-Yy5FV8Q=hUKRYO9zSbeUNSZn0g@mail.gmail.com> (raw)
In-Reply-To: <1534801939.10027.24.camel@amazon.co.uk>
On Mon, Aug 20, 2018 at 2:52 PM, Woodhouse, David <dwmw@amazon.co.uk> wrote:
> On Mon, 2018-08-20 at 14:48 -0700, Linus Torvalds wrote:
>>
>> Of course, after the long (and entirely unrelated) discussion about
>> the TLB flushing bug we had, I'm starting to worry about my own
>> competence, and maybe I'm missing something really fundamental, and
>> the XPFO patches do something else than what I think they do, or my
>> "hey, let's use our Meltdown code" idea has some fundamental weakness
>> that I'm missing.
>
> The interesting part is taking the user (and other) pages out of the
> kernel's 1:1 physmap.
>
> It's the *kernel* we don't want being able to access those pages,
> because of the multitude of unfixable cache load gadgets.
Right. And even before Meltdown, it was desirable to remove those from
the physmap to avoid SMAP (and in some cases SMEP) bypasses (as
detailed in the mentioned paper:
http://www.cs.columbia.edu/~vpk/papers/ret2dir.sec14.pdf).
-Kees
--
Kees Cook
Pixel Security
next prev parent reply other threads:[~2018-08-20 22:18 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-20 21:25 Redoing eXclusive Page Frame Ownership (XPFO) with isolated CPUs in mind (for KVM to isolate its guests per CPU) Konrad Rzeszutek Wilk
2018-08-20 21:48 ` Linus Torvalds
[not found] ` <1534801939.10027.24.camel@amazon.co.uk>
2018-08-20 22:18 ` Kees Cook [this message]
2018-08-20 22:27 ` Linus Torvalds
2018-08-20 22:35 ` Tycho Andersen
2018-08-20 22:59 ` Dave Hansen
2018-08-20 23:14 ` David Woodhouse
2018-08-20 23:26 ` Dave Hansen
2018-08-20 23:38 ` Linus Torvalds
2018-08-21 9:57 ` David Woodhouse
2018-08-21 14:01 ` Liran Alon
2018-08-21 14:22 ` David Woodhouse
2018-08-21 23:04 ` Liran Alon
2018-08-30 16:00 ` Julian Stecklina
2018-08-31 15:26 ` Tycho Andersen
2018-09-01 21:38 ` Linus Torvalds
2018-09-03 14:51 ` Julian Stecklina
2018-09-12 15:37 ` Julian Stecklina
2018-09-13 6:11 ` Juerg Haefliger
2018-09-17 10:01 ` Julian Stecklina
2018-09-17 10:19 ` Tycho Andersen
2018-09-17 13:27 ` Christoph Hellwig
2018-09-14 17:06 ` Khalid Aziz
2018-09-17 9:51 ` Julian Stecklina
2018-09-18 23:00 ` Khalid Aziz
2018-09-24 14:45 ` Stecklina, Julian
2018-10-15 8:07 ` Khalid Aziz
2018-10-24 11:00 ` Khalid Aziz
2018-10-24 15:00 ` Tycho Andersen
2018-09-03 15:26 ` Andi Kleen
2018-09-04 9:37 ` Julian Stecklina
[not found] ` <CACfEFw_h5uup-anKZwfBcWMJB7gHxb9NEPTRSUAY0+t11RiQbg@mail.gmail.com>
2018-09-03 15:36 ` Andi Kleen
2018-09-07 21:30 ` Khalid Aziz
2018-08-31 8:43 ` James Bottomley
2018-09-19 1:03 ` Balbir Singh
2018-09-19 15:43 ` Jonathan Adams
2018-09-23 2:33 ` Balbir Singh
2018-09-25 14:12 ` Stecklina, Julian
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