Patch "x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs without the feature" has been added to the 4.13-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs without the feature

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-apic-silence-fw_bug-tsc_deadline-disabled-due-to-errata-on-cpus-without-the-feature.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 594a30fb12424717a41c62323d2a8bf167dbccad Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Wed, 30 Aug 2017 12:58:11 +0200
Subject: x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs without the feature

From: Hans de Goede <hdegoede@redhat.com>

commit 594a30fb12424717a41c62323d2a8bf167dbccad upstream.

When booting 4.13 on a VirtualBox VM on a Skylake host the following
error shows up in the logs:

 [    0.000000] [Firmware Bug]: TSC_DEADLINE disabled due to Errata;
                please update microcode to version: 0xb2 (or later)

This is caused by apic_check_deadline_errata() only checking CPU model
and not the X86_FEATURE_TSC_DEADLINE_TIMER flag (which VirtualBox does
NOT export to the guest), combined with VirtualBox not exporting the
micro-code version to the guest.

This commit adds a check for X86_FEATURE_TSC_DEADLINE_TIMER to
apic_check_deadline_errata(), silencing this error on VirtualBox VMs.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frank Mehnert <frank.mehnert@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Thayer <michael.thayer@oracle.com>
Cc: Michal Necasek <michal.necasek@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: bd9240a18e ("x86/apic: Add TSC_DEADLINE quirk due to errata")
Link: http://lkml.kernel.org/r/20170830105811.27539-1-hdegoede@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/apic/apic.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -599,9 +599,13 @@ static const struct x86_cpu_id deadline_
 
 static void apic_check_deadline_errata(void)
 {
-	const struct x86_cpu_id *m = x86_match_cpu(deadline_match);
+	const struct x86_cpu_id *m;
 	u32 rev;
 
+	if (!boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER))
+		return;
+
+	m = x86_match_cpu(deadline_match);
 	if (!m)
 		return;
 


Patches currently in stable-queue which might be from hdegoede@redhat.com are

queue-4.13/x86-apic-silence-fw_bug-tsc_deadline-disabled-due-to-errata-on-hypervisors.patch
queue-4.13/x86-apic-silence-fw_bug-tsc_deadline-disabled-due-to-errata-on-cpus-without-the-feature.patch