From: Tycho Andersen <tycho@tycho.ws>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Woodhouse <dwmw@amazon.co.uk>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
juerg.haefliger@hpe.com, deepa.srinivasan@oracle.com,
Jim Mattson <jmattson@google.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
linux-mm <linux-mm@kvack.org>,
Thomas Gleixner <tglx@linutronix.de>,
joao.m.martins@oracle.com, pradeep.vincent@oracle.com,
Andi Kleen <ak@linux.intel.com>,
Khalid Aziz <khalid.aziz@oracle.com>,
kanth.ghatraju@oracle.com, Liran Alon <liran.alon@oracle.com>,
Kees Cook <keescook@google.com>,
jsteckli@os.inf.tu-dresden.de,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
chris.hyser@oracle.com, Tyler Hicks <tyhicks@canonical.com>,
John Haxby <john.haxby@oracle.com>, Jon Masters <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: Mon, 20 Aug 2018 16:35:57 -0600 [thread overview]
Message-ID: <20180820223557.GC16961@cisco.cisco.com> (raw)
In-Reply-To: <CA+55aFxyUdhYjnQdnmWAt8tTwn4HQ1xz3SAMZJiawkLpMiJ_+w@mail.gmail.com>
On Mon, Aug 20, 2018 at 03:27:52PM -0700, Linus Torvalds wrote:
> On Mon, Aug 20, 2018 at 3:02 PM Woodhouse, David <dwmw@amazon.co.uk> wrote:
> >
> > It's the *kernel* we don't want being able to access those pages,
> > because of the multitude of unfixable cache load gadgets.
>
> Ahh.
>
> I guess the proof is in the pudding. Did somebody try to forward-port
> that patch set and see what the performance is like?
>
> It used to be just 500 LOC. Was that because they took horrible
> shortcuts? Are the performance numbers for the 32-bit case that
> already had the kmap() overhead?
The last version I worked on was a bit before Meltdown was public:
https://lkml.org/lkml/2017/9/7/445
The overhead was a lot, but Dave Hansen gave some ideas about how to
speed things up in this thread: https://lkml.org/lkml/2017/9/20/828
Since meltdown hit, I haven't worked seriously on understand and
implementing his suggestions, in part because it wasn't clear to me
what pieces of the infrastructure we might be able to re-use. Someone
who knows more about mm/ might be able to suggest an approach, though.
Tycho
next prev parent reply other threads:[~2018-08-20 22:36 UTC|newest]
Thread overview: 52+ 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
2018-08-20 21:52 ` Woodhouse, David
2018-08-20 22:18 ` Kees Cook
2018-08-20 22:18 ` Kees Cook
2018-08-20 22:27 ` Linus Torvalds
2018-08-20 22:35 ` Tycho Andersen [this message]
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
2018-09-01 22:33 ` Wes Turner
2018-09-03 15:36 ` Andi Kleen
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 10:01 ` 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
2018-09-24 14:45 ` Stecklina, Julian
2018-10-15 8:07 ` Khalid Aziz
2018-10-15 8:07 ` Khalid Aziz
2018-10-24 11:00 ` Khalid Aziz
2018-10-24 11:00 ` Khalid Aziz
2018-10-24 15:00 ` Tycho Andersen
2018-10-24 15:00 ` Tycho Andersen
2018-09-03 15:26 ` Andi Kleen
2018-09-04 9:37 ` Julian Stecklina
2018-09-04 9:37 ` Julian Stecklina
2018-09-07 21:30 ` Khalid Aziz
2018-08-31 8:43 ` James Bottomley
2018-08-31 8:43 ` James Bottomley
2018-09-19 1:03 ` Balbir Singh
2018-09-19 1:03 ` Balbir Singh
2018-09-19 15:34 ` Jonathan Adams
2018-09-19 15:38 ` Jonathan Adams
2018-09-19 15:43 ` Jonathan Adams
2018-09-23 2:33 ` Balbir Singh
2018-09-25 14:12 ` Stecklina, Julian
2018-09-25 14:12 ` Stecklina, Julian
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