From: Don Zickus <dzickus@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
Suresh Siddha <suresh.b.siddha@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Prarit Bhargava <prarit@redhat.com>
Subject: Re: [PATCH] x86, x2apic: Only WARN on broken BIOSes inside a virtual guest
Date: Thu, 31 Jan 2013 14:34:27 -0500 [thread overview]
Message-ID: <20130131193427.GP98867@redhat.com> (raw)
In-Reply-To: <20130131185200.GA1757@redhat.com>
On Thu, Jan 31, 2013 at 08:52:00PM +0200, Gleb Natapov wrote:
> > http://www.invisiblethingslab.com/resources/2011/Software%20Attacks%20on%20Intel%20VT-d.pdf
> >
> > After talking with folks, the threat of irq injections on virtual guests
> > made sense. However, when discussing if this was possible on bare metal
> > machines, we could not come up with a plausible scenario.
> >
> The irq injections is something that a guest with assigned device does
> to attack a hypervisor it runs on. Interrupt remapping protects host
> from this attack. According to pdf above if x2apic is disabled in a
> hypervisor interrupt remapping can be bypassed and leave host vulnerable
> to guest attack. This means that situation is exactly opposite: warning
> has sense on a bare metal, but not in a guest. I am not sure that there is
> a hypervisor that emulates interrupt remapping device though and without
> it the warning cannot be triggered in a guest.
Ah, it makes sense. Not sure how I got it backwards then. So my patch is
pointless then? I'll asked for it to be dropped.
>From my previous discussions with folks, is that KVM was protected from
this type of attack. Is that still true?
Cheers,
Don
next prev parent reply other threads:[~2013-01-31 19:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 16:40 [PATCH] x86, x2apic: Only WARN on broken BIOSes inside a virtual guest Don Zickus
2013-01-31 18:52 ` Gleb Natapov
2013-01-31 19:34 ` Don Zickus [this message]
2013-01-31 20:00 ` Gleb Natapov
2013-01-31 20:52 ` Alex Williamson
2013-02-01 22:00 ` Andy Lutomirski
2013-02-01 22:57 ` [PATCH] intel_irq_remapping: Clean up x2apic optout security warning mess Andy Lutomirski
2013-02-03 19:29 ` [tip:x86/apic] x86/intel/irq_remapping: Clean up x2apic opt-out " tip-bot for Andy Lutomirski
2013-02-04 18:20 ` [PATCH] intel_irq_remapping: Clean up x2apic optout " Don Zickus
2013-02-04 19:04 ` Alex Williamson
2013-02-04 19:19 ` Andy Lutomirski
2013-02-04 19:39 ` Alex Williamson
2013-02-04 19:47 ` Andy Lutomirski
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