From: David Woodhouse <dwmw2@infradead.org>
To: Dave Hansen <dave.hansen@intel.com>,
Tycho Andersen <tycho@tycho.ws>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: 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: Tue, 21 Aug 2018 00:14:40 +0100 [thread overview]
Message-ID: <1534806880.10027.29.camel@infradead.org> (raw)
In-Reply-To: <bd148fb6-e139-a065-1bf5-8054f932d30a@intel.com>
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On Mon, 2018-08-20 at 15:59 -0700, Dave Hansen wrote:
> On 08/20/2018 03:35 PM, Tycho Andersen wrote:
> > 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
>
> Unfortunately, I'm not sure there's much of KPTI we can reuse. KPTI
> still has a very static kernel map (well, two static kernel maps) and
> XPFO really needs a much more dynamic map.
>
> We do have a bit of infrastructure now to do TLB flushes near the kernel
> exit point, but it's entirely for the user address space, which isn't
> affected by XPFO.
One option is to have separate kernel address spaces, both with and
without the full physmap.
If you need the physmap, then rather than manually mapping with 4KiB
pages, you just switch. Having first ensured that no malicious guest or
userspace is running on a sibling, of course.
I'm not sure it's a win, but it might be worth looking at.
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next prev parent reply other threads:[~2018-08-20 23:15 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 [this message]
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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