[PATCH v12 5/5] x86/cpufeature: enable RING3MWAIT for Knights Mill

From: Grzegorz Andrejczuk
Date: Fri Jan 20 2017 - 08:23:27 EST


From: Piotr Luc <piotr.luc@xxxxxxxxx>

Enable ring 3 MONITOR/MWAIT for Intel Xeon Phi
codenamed Knights Mill. We can't guarantee that this (KNM)
will be the last CPU model that needs this hack.
But, we do recognize that this is far from optimal,
and there is an effort to ensure we don't keep doing
extending this hack forever.

Signed-off-by: Piotr Luc <piotr.luc@xxxxxxxxx>
---
arch/x86/kernel/cpu/intel.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 213cbf0..b1b1af5 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -79,7 +79,9 @@ static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
* Ring 3 MONITOR/MWAIT feature cannot be detected without
* cpu model and family comparison.
*/
- if (c->x86 != 6 || c->x86_model != INTEL_FAM6_XEON_PHI_KNL)
+ if (c->x86 != 6 ||
+ (c->x86_model != INTEL_FAM6_XEON_PHI_KNL &&
+ c->x86_model != INTEL_FAM6_XEON_PHI_KNM))
return;

if (ring3mwait_disabled) {
--
2.5.1