From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: kernel-hardening@lists.openwall.com,
Liran Alon <liran.alon@oracle.com>,
Deepa Srinivasan <deepa.srinivasan@oracle.com>,
linux-mm@kvack.org, juerg.haefliger@hpe.com,
khalid.aziz@oracle.com, chris.hyser@oracle.com,
tyhicks@canonical.com, dwmw@amazon.co.uk, keescook@google.com,
andrew.cooper3@citrix.com, jcm@redhat.com,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Kanth <kanth.ghatraju@oracle.com>,
Joao Martins <joao.m.martins@oracle.com>,
jmattson@google.com, pradeep.vincent@oracle.com,
Linus Torvalds <torvalds@linux-foundation.org>,
ak@linux.intel.com, john.haxby@oracle.com,
jsteckli@os.inf.tu-dresden.de
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de
Subject: Redoing eXclusive Page Frame Ownership (XPFO) with isolated CPUs in mind (for KVM to isolate its guests per CPU)
Date: Mon, 20 Aug 2018 17:25:56 -0400 [thread overview]
Message-ID: <20180820212556.GC2230@char.us.oracle.com> (raw)
Hi!
See eXclusive Page Frame Ownership (https://lwn.net/Articles/700606/) which was posted
way back in in 2016..
In the last couple of months there has been a slew of CPU issues that have complicated
a lot of things. The latest - L1TF - is still fresh in folks's mind and it is
especially acute to virtualization workloads.
As such a bunch of various folks from different cloud companies (CCed) are looking
at a way to make Linux kernel be more resistant to hardware having these sort of
bugs.
In particular we are looking at a way to "remove as many mappings from the global
kernel address space as possible. Specifically, while being in the
context of process A, memory of process B should not be visible in the
kernel." (email from Julian Stecklina). That is the high-level view and
how this could get done, well, that is why posting this on
LKML/linux-hardening/kvm-devel/linux-mm to start the discussion.
Usually I would start with a draft of RFC patches so folks can rip it apart, but
thanks to other people (Juerg thank you!) it already exists:
(see https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1222756.html)
The idea would be to extend this to:
1) Only do it for processes that run under CPUS which are in isolcpus list.
2) Expand this to be a per-cpu page tables. That is each CPU has its own unique
set of pagetables - naturally _START_KERNEL -> __end would be mapped but the
rest would not.
Thoughts? Is this possible? Crazy? Better ideas?
next reply other threads:[~2018-08-20 21:26 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-20 21:25 Konrad Rzeszutek Wilk [this message]
2018-08-20 21:48 ` Redoing eXclusive Page Frame Ownership (XPFO) with isolated CPUs in mind (for KVM to isolate its guests per CPU) 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
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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