x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs without the...
authorHans de Goede <hdegoede@redhat.com>
Wed, 30 Aug 2017 10:58:11 +0000 (12:58 +0200)
committerIngo Molnar <mingo@kernel.org>
Thu, 31 Aug 2017 09:17:27 +0000 (11:17 +0200)
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>
arch/x86/kernel/apic/apic.c

index eebee4c..7834f73 100644 (file)
@@ -597,9 +597,13 @@ static const struct x86_cpu_id deadline_match[] = {
 
 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;