From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 12 May 2008 19:21:15 +0000 (+0200)
Subject: x86: prevent PGE flush from interruption/preemption
X-Git-Tag: v2.6.26-rc4~11^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1979a5fda7869a790f4fd83fb06c78498d26ba1;p=pandora-kernel.git

x86: prevent PGE flush from interruption/preemption

CR4 manipulation is not protected against interrupts and preemption,
but KVM uses smp_function_call to manipulate the X86_CR4_VMXE bit
either from the CPU hotplug code or from the kvm_init call.

We need to protect the CR4 manipulation from both interrupts and
preemption.

Original bug report: http://lkml.org/lkml/2008/5/7/48
Bugzilla entry: http://bugzilla.kernel.org/show_bug.cgi?id=10642

This is not a regression from 2.6.25, it's a long standing and hard to
trigger bug.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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