[PATCH for-4.13 0/2] Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on hypervisors

[PATCH for-4.13 0/2] Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on hypervisors

[Paolo Bonzini]

Both fixes cherry pick nicely, but only the second patch was submitted for
stable and therefore didn't apply; I'm sending out both now.

Paolo

Hans de Goede (1):
  x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs
    without the feature

Paolo Bonzini (1):
  x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on
    hypervisors

 arch/x86/kernel/apic/apic.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

-- 
2.14.2

[PATCH for-4.13 1/2] x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs without the feature

[Paolo Bonzini]

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

[ upstream commit 594a30fb12424717a41c62323d2a8bf167dbccad ]

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

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 98b3dd8cf2bf..b3273c842850 100644
--- 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_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;
 
-- 
2.14.2

[PATCH for-4.13 2/2] x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on hypervisors

[Paolo Bonzini]

[ upstream commit cc6afe2240298049585e86b1ade85efc8a7f225d ]

Commit 594a30fb1242 ("x86/apic: Silence "FW_BUG TSC_DEADLINE disabled
due to Errata" on CPUs without the feature", 2017-08-30) was also about
silencing the warning on VirtualBox; however, KVM does expose the TSC
deadline timer, and it's virtualized so that it is immune from CPU errata.

Therefore, booting 4.13 with "-cpu Haswell" shows this in the logs:

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

Even if you had a hypervisor that does _not_ virtualize the TSC deadline
and rather exposes the hardware one, it should be the hypervisors task
to update microcode and possibly hide the flag from CPUID.  So just
hide the message when running on _any_ hypervisor, not just those that
do not support the TSC deadline timer.

The older check still makes sense, so keep it.

Fixes: bd9240a18e ("x86/apic: Add TSC_DEADLINE quirk due to errata")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1507630377-54471-1-git-send-email-pbonzini@redhat.com
---
 arch/x86/kernel/apic/apic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index b3273c842850..a7be1b4283a0 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -602,7 +602,8 @@ static void apic_check_deadline_errata(void)
 	const struct x86_cpu_id *m;
 	u32 rev;
 
-	if (!boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER))
+	if (!boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER) ||
+	    boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return;
 
 	m = x86_match_cpu(deadline_match);
-- 
2.14.2

Re: [PATCH for-4.13 0/2] Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on hypervisors

[Greg KH]

On Wed, Oct 18, 2017 at 11:15:47AM +0200, Paolo Bonzini wrote:
> Both fixes cherry pick nicely, but only the second patch was submitted for
> stable and therefore didn't apply; I'm sending out both now.
> 
> Paolo
> 
> Hans de Goede (1):
>   x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs
>     without the feature
> 
> Paolo Bonzini (1):
>   x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on
>     hypervisors

Thanks, now applied.

greg k-h