From nobody Thu Sep 18 08:47:43 2025 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 A6715C352A1 for ; Wed, 7 Dec 2022 11:29:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230039AbiLGL3i (ORCPT ); Wed, 7 Dec 2022 06:29:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230058AbiLGL3e (ORCPT ); Wed, 7 Dec 2022 06:29:34 -0500 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00E8547304 for ; Wed, 7 Dec 2022 03:29:33 -0800 (PST) Received: by mail-yb1-xb4a.google.com with SMTP id i19-20020a253b13000000b0070358cca7f7so4902765yba.9 for ; Wed, 07 Dec 2022 03:29:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=io7txIjxWH6pJVXEI7Hxrn83i6WbHyJAQOFZka8ddgg=; b=Au1I/GqNOl4lybF3LIlQtIcU2l9cxCRe1QfmEW4fw92Ey/0wqzuku7b+yTlT7mOjuF AFsJypsJppZG8+tKZ+8l+NUfWopF3nR7Vfc03Yg4DE+ZwSSz9pDLZGhYKpzayV+DQUgL 31kKadJ/OffOKwwPGK0avlB0pahEHypEg5Cc5Jxbt5nJPp6TWVy5Du0G7gSxaJ1X2DVY uOUq9JgOBAIQoGL8Dn5ffesmHkO1z6qrxItgjpZpdp9DNZQKHdAcjlx/1pJCzhVUpLX4 lpsK88Pb9zgheJPp/U/PRH/b3tcuCJGmCPo/AGHb3NTStKx2/fpw9tLn8ni5MmlV8tSg yyCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=io7txIjxWH6pJVXEI7Hxrn83i6WbHyJAQOFZka8ddgg=; b=GKJDKTb/HHqSlasHWfVWgR2oXxmvMKmpPt8Qf7gSuiGOyqSOwG1KEdlv66oFEoeANL zbPdTRAZf1HESUqReUsJzTaYf/AlTCOn7RHwiCc4pI8UH9WvXoyAj9gk/03kyq3ghGBd AI49moaZknMlHELoDa0QpNtcgrzD3xqGaLtKyuM0K0N1xl/zopJ0VpNZDUJktanPeVlG hprAmAEdH2bgQwoVTOrLS7+rHoOhQwtxMUDEjLS7pdyHXYor43nQxH6Rq6ZYse/VdF1x 5SuCA3oES3NITykha+ROvdMOgNMP+zbK1FkS8PbWtNnOBNLyPKWlnyRKWFfxIhBToLPu ujEQ== X-Gm-Message-State: ANoB5pk9deHDos4QQRyzj+J2HDDf4nQ+N/Aob9ITarX/fv6drWWb4YKF FIA4rO/aKJtKYA15ecDMWIPjGAzPQc1rr5ufeQ== X-Google-Smtp-Source: AA0mqf4OEiSIHezAUsM2xUHu6RfGjAOI4hyDSXkl7rNwOK3p6hyEDw40rm3mH8UonKFrBi7/dRF2cJ7ZgMmf+HNIrw== X-Received: from peternewman10.zrh.corp.google.com ([2a00:79e0:9d:6:d6fd:f294:ba46:7a93]) (user=peternewman job=sendgmr) by 2002:a81:110f:0:b0:3c3:ed97:3ea3 with SMTP id 15-20020a81110f000000b003c3ed973ea3mr45636117ywr.198.1670412572260; Wed, 07 Dec 2022 03:29:32 -0800 (PST) Date: Wed, 7 Dec 2022 12:29:24 +0100 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog Message-ID: <20221207112924.3602960-1-peternewman@google.com> Subject: [PATCH] x86/resctrl: Fix event counts regression in reused RMIDs From: Peter Newman To: Fenghua Yu , Reinette Chatre Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , James Morse , Shaopeng Tan , Jamie Iles , linux-kernel@vger.kernel.org, eranian@google.com, Peter Newman Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When creating a new monitoring group, the RMID allocated for it may have been used by a group which was previously removed. In this case, the hardware counters will have non-zero values which should be deducted from what is reported in the new group's counts. resctrl_arch_reset_rmid() initializes the prev_msr value for counters to 0, causing the initial count to be charged to the new group. Resurrect __rmid_read() and use it to initialize prev_msr correctly. Fixes: 1d81d15db39c ("x86/resctrl: Move mbm_overflow_count() into resctrl_a= rch_rmid_read()") Signed-off-by: Peter Newman --- arch/x86/kernel/cpu/resctrl/monitor.c | 39 ++++++++++++++++++--------- 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/re= sctrl/monitor.c index efe0c30d3a12..404dd9c472c7 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -146,6 +146,24 @@ static inline struct rmid_entry *__rmid_entry(u32 rmid) return entry; } +static u64 __rmid_read(u32 rmid, enum resctrl_event_id eventid) +{ + u64 val; + + /* + * As per the SDM, when IA32_QM_EVTSEL.EvtID (bits 7:0) is configured + * with a valid event code for supported resource type and the bits + * IA32_QM_EVTSEL.RMID (bits 41:32) are configured with valid RMID, + * IA32_QM_CTR.data (bits 61:0) reports the monitored data. + * IA32_QM_CTR.Error (bit 63) and IA32_QM_CTR.Unavailable (bit 62) + * are error bits. + */ + wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid); + rdmsrl(MSR_IA32_QM_CTR, val); + + return val; +} + static struct arch_mbm_state *get_arch_mbm_state(struct rdt_hw_domain *hw_= dom, u32 rmid, enum resctrl_event_id eventid) @@ -170,10 +188,17 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, = struct rdt_domain *d, { struct rdt_hw_domain *hw_dom =3D resctrl_to_arch_dom(d); struct arch_mbm_state *am; + uint64_t val; am =3D get_arch_mbm_state(hw_dom, rmid, eventid); - if (am) + if (am) { memset(am, 0, sizeof(*am)); + + /* Record any initial, non-zero count value. */ + val =3D __rmid_read(rmid, eventid); + if (!(val & (RMID_VAL_ERROR | RMID_VAL_UNAVAIL))) + am->prev_msr =3D val; + } } static u64 mbm_overflow_count(u64 prev_msr, u64 cur_msr, unsigned int widt= h) @@ -195,17 +220,7 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, str= uct rdt_domain *d, if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask)) return -EINVAL; - /* - * As per the SDM, when IA32_QM_EVTSEL.EvtID (bits 7:0) is configured - * with a valid event code for supported resource type and the bits - * IA32_QM_EVTSEL.RMID (bits 41:32) are configured with valid RMID, - * IA32_QM_CTR.data (bits 61:0) reports the monitored data. - * IA32_QM_CTR.Error (bit 63) and IA32_QM_CTR.Unavailable (bit 62) - * are error bits. - */ - wrmsr(MSR_IA32_QM_EVTSEL, eventid, rmid); - rdmsrl(MSR_IA32_QM_CTR, msr_val); - + msr_val =3D __rmid_read(rmid, eventid); if (msr_val & RMID_VAL_ERROR) return -EIO; if (msr_val & RMID_VAL_UNAVAIL) base-commit: 76dcd734eca23168cb008912c0f69ff408905235 -- 2.39.0.rc0.267.gcb52ba06e7-goog