From: Avi Kivity <avi@redhat.com>
Date: Thu, 6 Aug 2009 17:40:00 +0000 (-0300)
Subject: KVM: Make EFER reads safe when EFER does not exist
X-Git-Tag: v2.6.27.32~25
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f06f0605b998dfe1453380bfff72bd861ca3a016;p=pandora-kernel.git

KVM: Make EFER reads safe when EFER does not exist

(cherry picked from commit e286e86e6d2042d67d09244aa0e05ffef75c9d54)

Some processors don't have EFER; don't oops if userspace wants us to
read EFER when we check NX.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1454992e6ace..662cf12d1db9 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -983,9 +983,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 
 static int is_efer_nx(void)
 {
-	u64 efer;
+	unsigned long long efer = 0;
 
-	rdmsrl(MSR_EFER, efer);
+	rdmsrl_safe(MSR_EFER, &efer);
 	return efer & EFER_NX;
 }