From nobody Sun Jun 14 12:19:46 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A0E6C433EF for ; Wed, 18 May 2022 04:56:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230089AbiERE4k (ORCPT ); Wed, 18 May 2022 00:56:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230077AbiERE4h (ORCPT ); Wed, 18 May 2022 00:56:37 -0400 Received: from esa12.hc1455-7.c3s2.iphmx.com (esa12.hc1455-7.c3s2.iphmx.com [139.138.37.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BB122E6AD for ; Tue, 17 May 2022 21:56:34 -0700 (PDT) X-IronPort-AV: E=McAfee;i="6400,9594,10350"; a="52840604" X-IronPort-AV: E=Sophos;i="5.91,234,1647270000"; d="scan'208";a="52840604" Received: from unknown (HELO yto-r1.gw.nic.fujitsu.com) ([218.44.52.217]) by esa12.hc1455-7.c3s2.iphmx.com with ESMTP; 18 May 2022 13:56:32 +0900 Received: from yto-m3.gw.nic.fujitsu.com (yto-nat-yto-m3.gw.nic.fujitsu.com [192.168.83.66]) by yto-r1.gw.nic.fujitsu.com (Postfix) with ESMTP id 1CEDBE5B22 for ; Wed, 18 May 2022 13:56:31 +0900 (JST) Received: from oym-om3.fujitsu.com (oym-om3.o.css.fujitsu.com [10.85.58.163]) by yto-m3.gw.nic.fujitsu.com (Postfix) with ESMTP id 54204D96DE for ; Wed, 18 May 2022 13:56:30 +0900 (JST) Received: from cn-r05-10.example.com (n3235113.np.ts.nmh.cs.fujitsu.co.jp [10.123.235.113]) by oym-om3.fujitsu.com (Postfix) with ESMTP id 29000403E921D; Wed, 18 May 2022 13:56:30 +0900 (JST) From: Kohei Tarumizu To: fenghua.yu@intel.com, reinette.chatre@intel.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org Subject: [PATCH] x86/resctrl: Fix to restore to original value when re-enabling hardware prefetch register Date: Wed, 18 May 2022 13:55:17 +0900 Message-Id: <20220518045517.2066518-1-tarumizu.kohei@fujitsu.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The current pseudo_lock.c code overwrites the value of the MSR_MISC_FEATURE_CONTROL to 0 even if the original value is not 0. Therefore, modify it to save and restore the original values. Fixes: 018961ae5579 ("x86/intel_rdt: Pseudo-lock region creation/removal co= re") Fixes: 443810fe6160 ("x86/intel_rdt: Create debugfs files for pseudo-lockin= g testing") Fixes: 8a2fc0e1bc0c ("x86/intel_rdt: More precise L2 hit/miss measurements") Signed-off-by: Kohei Tarumizu Acked-by: Reinette Chatre --- This patch was previously one of the following my patch series:. https://lore.kernel.org/lkml/20220420030223.689259-7-tarumizu.kohei@fujitsu= .com/ However, it doesn't depend on my patch series, so I extracted it as a separate patch. Best regards, Kohei Tarumizu --- arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cp= u/resctrl/pseudo_lock.c index db813f819ad6..4d8398986f78 100644 --- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c +++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c @@ -420,6 +420,7 @@ static int pseudo_lock_fn(void *_rdtgrp) struct pseudo_lock_region *plr =3D rdtgrp->plr; u32 rmid_p, closid_p; unsigned long i; + u64 saved_msr; #ifdef CONFIG_KASAN /* * The registers used for local register variables are also used @@ -463,6 +464,7 @@ static int pseudo_lock_fn(void *_rdtgrp) * the buffer and evict pseudo-locked memory read earlier from the * cache. */ + saved_msr =3D __rdmsr(MSR_MISC_FEATURE_CONTROL); __wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0); closid_p =3D this_cpu_read(pqr_state.cur_closid); rmid_p =3D this_cpu_read(pqr_state.cur_rmid); @@ -514,7 +516,7 @@ static int pseudo_lock_fn(void *_rdtgrp) __wrmsr(IA32_PQR_ASSOC, rmid_p, closid_p); =20 /* Re-enable the hardware prefetcher(s) */ - wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0); + wrmsrl(MSR_MISC_FEATURE_CONTROL, saved_msr); local_irq_enable(); =20 plr->thread_done =3D 1; @@ -871,6 +873,7 @@ bool rdtgroup_pseudo_locked_in_hierarchy(struct rdt_dom= ain *d) static int measure_cycles_lat_fn(void *_plr) { struct pseudo_lock_region *plr =3D _plr; + u32 saved_low, saved_high; unsigned long i; u64 start, end; void *mem_r; @@ -879,6 +882,7 @@ static int measure_cycles_lat_fn(void *_plr) /* * Disable hardware prefetchers. */ + rdmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0); mem_r =3D READ_ONCE(plr->kmem); /* @@ -895,7 +899,7 @@ static int measure_cycles_lat_fn(void *_plr) end =3D rdtsc_ordered(); trace_pseudo_lock_mem_latency((u32)(end - start)); } - wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0); + wrmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); local_irq_enable(); plr->thread_done =3D 1; wake_up_interruptible(&plr->lock_thread_wq); @@ -940,6 +944,7 @@ static int measure_residency_fn(struct perf_event_attr = *miss_attr, u64 hits_before =3D 0, hits_after =3D 0, miss_before =3D 0, miss_after = =3D 0; struct perf_event *miss_event, *hit_event; int hit_pmcnum, miss_pmcnum; + u32 saved_low, saved_high; unsigned int line_size; unsigned int size; unsigned long i; @@ -973,6 +978,7 @@ static int measure_residency_fn(struct perf_event_attr = *miss_attr, /* * Disable hardware prefetchers. */ + rdmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); wrmsr(MSR_MISC_FEATURE_CONTROL, prefetch_disable_bits, 0x0); =20 /* Initialize rest of local variables */ @@ -1031,7 +1037,7 @@ static int measure_residency_fn(struct perf_event_att= r *miss_attr, */ rmb(); /* Re-enable hardware prefetchers */ - wrmsr(MSR_MISC_FEATURE_CONTROL, 0x0, 0x0); + wrmsr(MSR_MISC_FEATURE_CONTROL, saved_low, saved_high); local_irq_enable(); out_hit: perf_event_release_kernel(hit_event); --=20 2.27.0