[PATCH] KVM: VMX: Inform user about INTEL_TXT dependency

[Jan Kiszka <jan.kiszka@web.de>]

From: Jan Kiszka <jan.kiszka@siemens.com>

Without CONFIG_INTEL_TXT, the user must not enable this feature in the
BIOS. Otherwise, KVM will not work. Explain this dependency via a kernel
log message.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 arch/x86/kvm/vmx.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9367abc..ebafd57 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1306,8 +1306,13 @@ static __init int vmx_disabled_by_bios(void)
 			&& tboot_enabled())
 			return 1;
 		if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
-			&& !tboot_enabled())
+			&& !tboot_enabled()) {
+#ifndef CONFIG_INTEL_TXT
+			printk(KERN_INFO "kvm: if TXT is enabled in the bios, "
+					 "kvm depends on CONFIG_INTEL_TXT\n");
+#endif
 			return 1;
+		}
 	}
 
 	return 0;
-- 
1.7.1