From mboxrd@z Thu Jan 1 00:00:00 1970 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7F8F2CAC5B0 for ; Fri, 3 Oct 2025 12:22:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C8AC28E0007; Fri, 3 Oct 2025 08:22:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C61EC8E0003; Fri, 3 Oct 2025 08:22:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B9F938E0007; Fri, 3 Oct 2025 08:22:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id A718B8E0003 for ; Fri, 3 Oct 2025 08:22:44 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 4846F1A074E for ; Fri, 3 Oct 2025 12:22:44 +0000 (UTC) X-FDA: 83956716648.05.8066C22 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by imf15.hostedemail.com (Postfix) with ESMTP id 5F008A0009 for ; Fri, 3 Oct 2025 12:22:42 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=none; spf=pass (imf15.hostedemail.com: domain of jonathan.cameron@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=jonathan.cameron@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1759494162; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OeDVDlwSeC1BlDNuZhiAP1Uyu1ZwbSRhEUGWJoBsNQI=; b=cHQI0PChUCuG9Rrwme+TBGE4JAHwZGJNrxkrX66KTDc6MYaZLW6pdsVCxPp106GI7IpiwP ksA48jeup1wpcZpP8rekKOvcV8CsHse3kyBeOZrz9CB9PP2IEKbRNVIuNRY/E2lraNWugE 2w9BB4RhidVk2sjdZuju1UkSkOuJ4o4= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759494162; a=rsa-sha256; cv=none; b=Hnb9zA7UP5BPUd2pLJcH2scTqTGK2xD9VPNXpVRK+eoayLI2IpgW2MP6ot1nbGv79hZKzU eA84yiOVm0Kw84KUmaO8ShMEvVnE67HbLddER7Xh+p3fy9g72JPBgZmjG39UhY1gunTXFj 8MtHlQ4MHnUlQsYGQBjbuNybKC8/Bi8= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=none; spf=pass (imf15.hostedemail.com: domain of jonathan.cameron@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=jonathan.cameron@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.216]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4cdSQS4xR6z6K8Xc; Fri, 3 Oct 2025 20:19:28 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 07A4E140372; Fri, 3 Oct 2025 20:22:40 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 3 Oct 2025 13:22:38 +0100 Date: Fri, 3 Oct 2025 13:22:36 +0100 From: Jonathan Cameron To: Bharata B Rao CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [RFC PATCH v2 5/8] x86: ibs: Enable IBS profiling for memory accesses Message-ID: <20251003132236.00002ecd@huawei.com> In-Reply-To: <20250910144653.212066-6-bharata@amd.com> References: <20250910144653.212066-1-bharata@amd.com> <20250910144653.212066-6-bharata@amd.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.203.177.15] X-ClientProxiedBy: lhrpeml500012.china.huawei.com (7.191.174.4) To dubpeml100005.china.huawei.com (7.214.146.113) X-Rspamd-Queue-Id: 5F008A0009 X-Stat-Signature: 6dsbgamfd3w3oe3snaaufm8a1n5trscs X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1759494162-431401 X-HE-Meta: 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 ThVgJIJo LcXM/efn4lJKMYxGdvi4vimhIsnd1k22dW7pnv+KGzBX+K7eQhtKq5TaRPFqBhA9kc7yybtyAR2OgyRN/Tcm5zOTrLgQfOwCvR+XPEPQGWKWaFvS8XWvSen1RVr+iKKvpTpmgRDsqbF1Ebh+/zz3K/wJRx63STUHsdMZrEMNzVVYVBMYNlfOuf2qde/VsB1R5bbeCJxkNd001XGVQoCDLgbvXCq7Zu6eEXmka9Ql/89EsRMm+iWeba3uRwMOmGwfVpXsL5hbWxlENoDV9i/QRHxkmKUOnG7RL9iW1n8QVVd2mQgau1DNjTKuqplmJx13rWQEq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, 10 Sep 2025 20:16:50 +0530 Bharata B Rao wrote: > Enable IBS memory access data collection for user memory > accesses by programming the required MSRs. The profiling > is turned ON only for user mode execution and turned OFF > for kernel mode execution. Profiling is explicitly disabled > for NMI handler too. > > TODOs: > > - IBS sampling rate is kept fixed for now. > - Arch/vendor separation/isolation of the code needs relook. > > Signed-off-by: Bharata B Rao One "oops I misread it" wrt to review of previous patch. + a really trivial thing. J > --- > arch/x86/include/asm/entry-common.h | 3 +++ > arch/x86/include/asm/hardirq.h | 2 ++ > arch/x86/include/asm/ibs.h | 2 ++ > arch/x86/mm/ibs.c | 32 +++++++++++++++++++++++++++++ > 4 files changed, 39 insertions(+) > diff --git a/arch/x86/mm/ibs.c b/arch/x86/mm/ibs.c > index 6669710dd35b..3128e8fa5f39 100644 > --- a/arch/x86/mm/ibs.c > +++ b/arch/x86/mm/ibs.c > @@ -16,6 +16,7 @@ static u64 ibs_config __read_mostly; > static u32 ibs_caps; > > #define IBS_NR_SAMPLES 150 > +#define IBS_SAMPLE_PERIOD 10000 > > /* > * Basic access info captured for each memory access. > @@ -98,6 +99,36 @@ static void ibs_irq_handler(struct irq_work *i) > schedule_work_on(smp_processor_id(), &ibs_work); > } > > +void hw_access_profiling_stop(void) > +{ > + u64 ops_ctl; > + > + if (!arch_hw_access_profiling) > + return; > + > + rdmsrl(MSR_AMD64_IBSOPCTL, ops_ctl); > + wrmsrl(MSR_AMD64_IBSOPCTL, ops_ctl & ~IBS_OP_ENABLE); > +} > + > +void hw_access_profiling_start(void) > +{ > + u64 config = 0; > + unsigned int period = IBS_SAMPLE_PERIOD; > + > + if (!arch_hw_access_profiling) > + return; > + > + /* Disable IBS for kernel thread */ > + if (!current->mm) > + goto out; > + > + config = (period >> 4) & IBS_OP_MAX_CNT; Bonus space though before & that can go. > + config |= (period & IBS_OP_MAX_CNT_EXT_MASK); > + config |= ibs_config; Ah. Ignore comment in previous patch on this not being global. Clearly it needs to be. Oops I misread this earlier. > +out: > + wrmsrl(MSR_AMD64_IBSOPCTL, config); > +} > + > /* > * IBS NMI handler: Process the memory access info reported by IBS. > * > @@ -304,6 +335,7 @@ static int __init ibs_access_profiling_init(void) > x86_amd_ibs_access_profile_startup, > x86_amd_ibs_access_profile_teardown); > > + arch_hw_access_profiling = true; > pr_info("IBS setup for memory access profiling\n"); > return 0; > }