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From: Balbir Singh <bsingharora@gmail.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>,
	"deepa.srinivasan@oracle.com" <deepa.srinivasan@oracle.com>,
	"jmattson@google.com" <jmattson@google.com>,
	"andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"boris.ostrovsky@oracle.com" <boris.ostrovsky@oracle.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"joao.m.martins@oracle.com" <joao.m.martins@oracle.com>,
	"pradeep.vincent@oracle.com" <pradeep.vincent@oracle.com>,
	"ak@linux.intel.com" <ak@linux.intel.com>,
	"khalid.aziz@oracle.com" <khalid.aziz@oracle.com>,
	"kanth.ghatraju@oracle.com" <kanth.ghatraju@oracle.com>,
	"liran.alon@oracle.com" <liran.alon@oracle.com>,
	"keescook@google.com" <keescook@google.com>,
	"jsteckli@os.inf.tu-dresden.de" <jsteckli@os.inf.tu-dresden.de>,
	"kernel-hardening@lists.openwall.com" 
	<kernel-hardening@lists.openwall.com>,
	"chris.hyser@oracle.com" <chris.hyser@oracle.com>,
	"tyhicks@canonical.com" <tyhicks@canonical.com>,
	"john.haxby@oracle.com" <john.haxby@oracle.com>,
	"jcm@redhat.com" <jcm@redhat.com>
Subject: Re: Redoing eXclusive Page Frame Ownership (XPFO) with isolated CPUs in mind (for KVM to isolate its guests per CPU)
Date: Wed, 19 Sep 2018 11:03:37 +1000	[thread overview]
Message-ID: <20180919010337.GC8537@350D> (raw)
In-Reply-To: <1534801939.10027.24.camel@amazon.co.uk>

On Mon, Aug 20, 2018 at 09:52:19PM +0000, Woodhouse, David 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.

I am missing why we need this since the kernel can't access
(SMAP) unless we go through to the copy/to/from interface
or execute any of the user pages. Is it because of the dependency
on the availability of those features?

Balbir Singh.


  parent reply	other threads:[~2018-09-19  1:03 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
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 [this message]
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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