From 3553e5d34d72a3aac5d967ec8b4d45a88340d679 Mon Sep 17 00:00:00 2001
From: Eric Northup <digitaleric@google.com>
Date: Tue, 3 Nov 2015 18:03:53 +0100
Subject: [PATCH] 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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