From: Eric Northup <digitaleric@google.com>
Date: Tue, 3 Nov 2015 17:03:53 +0000 (+0100)
Subject: KVM: x86: work around infinite loop in microcode when #AC is delivered
X-Git-Tag: v3.2.73~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3553e5d34d72a3aac5d967ec8b4d45a88340d679;p=pandora-kernel.git

KVM: x86: work around infinite loop in microcode when #AC is delivered

commit 54a20552e1eae07aa240fa370a0293e006b5faed upstream.

It was found that a guest can DoS a host by triggering an infinite
stream of "alignment check" (#AC) exceptions.  This causes the
microcode to enter an infinite loop where the core never receives
another interrupt.  The host kernel panics pretty quickly due to the
effects (CVE-2015-5307).

Signed-off-by: Eric Northup <digitaleric@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.2:
 - Add definition of AC_VECTOR
 - Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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