KVM: x86: Check LMA bit before set_efer

kvm_x86_ops->set_efer() would execute vcpu->arch.efer = efer, so the
checking of LMA bit didn't work.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/x86.c

@@ -709,11 +709,11 @@ static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
 			return 1;
 	}
 
-	kvm_x86_ops->set_efer(vcpu, efer);
-
 	efer &= ~EFER_LMA;
 	efer |= vcpu->arch.efer & EFER_LMA;
 
+	kvm_x86_ops->set_efer(vcpu, efer);
+
 	vcpu->arch.efer = efer;
 
 	vcpu->arch.mmu.base_role.nxe = (efer & EFER_NX) && !tdp_enabled;