KVM: VMX: fix detection of BIOS disabling VMX

This patch fixes the logic used to detect whether BIOS has disabled VMX, for
the case where VMX is enabled only under SMX, but tboot is not active.

Signed-off-by:  Joseph Cihula <joseph.cihula@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/vmx.c

@@ -1333,19 +1333,25 @@ static __init int vmx_disabled_by_bios(void)
 
 	rdmsrl(MSR_IA32_FEATURE_CONTROL, msr);
 	if (msr & FEATURE_CONTROL_LOCKED) {
+		/* launched w/ TXT and VMX disabled */
 		if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
 			&& tboot_enabled())
 			return 1;
+		/* launched w/o TXT and VMX only enabled w/ TXT */
 		if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
+			&& (msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
 			&& !tboot_enabled()) {
 			printk(KERN_WARNING "kvm: disable TXT in the BIOS or "
-				" activate TXT before enabling KVM\n");
+				"activate TXT before enabling KVM\n");
 			return 1;
 		}
+		/* launched w/o TXT and VMX disabled */
+		if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
+			&& !tboot_enabled())
+			return 1;
 	}
 
 	return 0;
-	/* locked but not enabled */
 }
 
 static void kvm_cpu_vmxon(u64 addr)