KVM: VMX: Don't allow uninhibited access to EFER on i386

upstream 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@cs.cmu.edu>
Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7611af576829d820eba8de4a79d389e8baef7759..90de4443ef41b90b220121b24990bba2b4807e77 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -928,11 +928,11 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
        int ret = 0;
 
        switch (msr_index) {
-#ifdef CONFIG_X86_64
        case MSR_EFER:
                vmx_load_host_state(vmx);
                ret = kvm_set_msr_common(vcpu, msr_index, data);
                break;
+#ifdef CONFIG_X86_64
        case MSR_FS_BASE:
                vmcs_writel(GUEST_FS_BASE, data);
                break;