linux-kernel - [PATCH v10 5/5] x86/cpufeature: enable RING3MWAIT for Knights Mill

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 16 Dec 2016 19:00:04 +0100
From:   Grzegorz Andrejczuk <grzegorz.andrejczuk@...el.com>
To:     tglx@...utronix.de, mingo@...hat.com, hpa@...or.com, x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, Piotr.Luc@...el.com,
        dave.hansen@...ux.intel.com, Piotr Luc <piotr.luc@...el.com>
Subject: [PATCH v10 5/5] x86/cpufeature: enable RING3MWAIT for Knights Mill

From: Piotr Luc <piotr.luc@...el.com>

This patch enables 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@...el.com>
---
 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 70d4985..1507c7c 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -78,7 +78,9 @@ 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