[patch 23/48] KVM: VMX: Dont allow uninhibited access to EFER on i386

From: Greg KH
Date: Fri Sep 04 2009 - 16:19:56 EST

2.6.27-stable review patch. If anyone has any objections, please let us know.

From: Avi Kivity <avi@xxxxxxxxxx>

(cherry picked from commit 16175a796d061833aacfbd9672235f2d2725df65)

vmx_set_msr() does not allow i386 guests to touch EFER, but they can still
do so through the default: label in the switch. If they set EFER_LME, they
can oops the host.

Fix by having EFER access through the normal channel (which will check for
EFER_LME) even on i386.

Reported-and-tested-by: Benjamin Gilbert <bgilbert@xxxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
arch/x86/kvm/vmx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -898,11 +898,11 @@ static int vmx_set_msr(struct kvm_vcpu *
int ret = 0;

switch (msr_index) {
-#ifdef CONFIG_X86_64
case MSR_EFER:
ret = kvm_set_msr_common(vcpu, msr_index, data);
+#ifdef CONFIG_X86_64
vmcs_writel(GUEST_FS_BASE, data);

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/