linux-kernel - [tip:x86/pti] x86/l1tf: Show actual SMT state

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Date:   Wed, 28 Nov 2018 06:26:43 -0800
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     david.c.stewart@...el.com, longman9394@...il.com,
        casey.schaufler@...el.com, jkosina@...e.cz,
        torvalds@...ux-foundation.org, tglx@...utronix.de,
        peterz@...radead.org, dwmw@...zon.co.uk, mingo@...nel.org,
        gregkh@...uxfoundation.org, hpa@...or.com,
        asit.k.mallick@...el.com, ak@...ux.intel.com,
        arjan@...ux.intel.com, keescook@...omium.org, luto@...nel.org,
        linux-kernel@...r.kernel.org, aarcange@...hat.com,
        jpoimboe@...hat.com, dave.hansen@...el.com,
        tim.c.chen@...ux.intel.com, jcm@...hat.com, thomas.lendacky@....com
Subject: [tip:x86/pti] x86/l1tf: Show actual SMT state

Commit-ID:  130d6f946f6f2a972ee3ec8540b7243ab99abe97
Gitweb:     https://git.kernel.org/tip/130d6f946f6f2a972ee3ec8540b7243ab99abe97
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Sun, 25 Nov 2018 19:33:40 +0100
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Wed, 28 Nov 2018 11:57:08 +0100

x86/l1tf: Show actual SMT state

Use the now exposed real SMT state, not the SMT sysfs control knob
state. This reflects the state of the system when the mitigation status is
queried.

This does not change the warning in the VMX launch code. There the
dependency on the control knob makes sense because siblings could be
brought online anytime after launching the VM.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Ingo Molnar <mingo@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Jiri Kosina <jkosina@...e.cz>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Cc: David Woodhouse <dwmw@...zon.co.uk>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Casey Schaufler <casey.schaufler@...el.com>
Cc: Asit Mallick <asit.k.mallick@...el.com>
Cc: Arjan van de Ven <arjan@...ux.intel.com>
Cc: Jon Masters <jcm@...hat.com>
Cc: Waiman Long <longman9394@...il.com>
Cc: Greg KH <gregkh@...uxfoundation.org>
Cc: Dave Stewart <david.c.stewart@...el.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: stable@...r.kernel.org
Link: https://lkml.kernel.org/r/20181125185004.613357354@linutronix.de


---
 arch/x86/kernel/cpu/bugs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 5625b323ff32..2dc4ee2bedcb 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -832,13 +832,14 @@ static ssize_t l1tf_show_state(char *buf)
 
 	if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_EPT_DISABLED ||
 	    (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER &&
-	     cpu_smt_control == CPU_SMT_ENABLED))
+	     sched_smt_active())) {
 		return sprintf(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG,
 			       l1tf_vmx_states[l1tf_vmx_mitigation]);
+	}
 
 	return sprintf(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG,
 		       l1tf_vmx_states[l1tf_vmx_mitigation],
-		       cpu_smt_control == CPU_SMT_ENABLED ? "vulnerable" : "disabled");
+		       sched_smt_active() ? "vulnerable" : "disabled");
 }
 #else
 static ssize_t l1tf_show_state(char *buf)