From patchwork Mon Feb 27 16:09:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Uros Bizjak X-Patchwork-Id: 61992 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp2515490wrd; Mon, 27 Feb 2023 08:28:15 -0800 (PST) X-Google-Smtp-Source: AK7set9xKd6pVsiIfsU39UW93tn+8UUk+D5oyk7tbRFDXCVC61VL3DE72XehOa/mUAYPWq6uvTEm X-Received: by 2002:a05:6402:711:b0:4af:593c:bf77 with SMTP id w17-20020a056402071100b004af593cbf77mr19284edx.33.1677515294896; Mon, 27 Feb 2023 08:28:14 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677515294; cv=none; d=google.com; s=arc-20160816; b=cnnHBU4TG3fhvWeXPOpv1tJ8ZJlDtWSVGAZipzsmnc8/yUjWYIrM8ZRAPC+FKFxBez Mqkrt7NePce/eSWmaJyyrJHMcx7o/3gJqA0CvvMMsZZ24ttIDLuzwAkQ5vyAO64BXNiT M0VlTwGUOzdXuGQAJqr8kDvPrPLjvLw/oHRxYnPY6cqcG99OTE4XBqkROf4AA98PKiY+ w7veB4SP/S63tHIjo4fZFbSHVlScrDD3+MSYl4brOe+pJQ93IGImuHrVeRaPc1txh2m/ YYHIuoXYtkM170GNG7EMbv0/fHFFgV2B5gpYeMTHh+9IKz+q7cTyvyVEofu5kYxVUC6I IiQA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:dkim-signature; bh=oxey+7sqWvWOo5NrntHk/o4WUHBkJNfXPSn9nqQN0fs=; b=Ym6eHrQIWdsXmrl0hd2UrMS7UctEhi4+cJoIjrJkiLEtBsAqx7iPiGSHMFCSF4Ipl5 8HHzQUnp9ffZRPw0DMEs5ujeMydakRvvdbR/BmnzGvLKGCO7pCzGz5K1d0I9EkmgvM3+ D+2HhPxS/T5bwjS98F4BhNjc/mFrDmCj1Dl5eeu5JTE8VqMpU81CM/Kt95U1/4Niu677 zq5hL+BJypsurHltucFZYpQCgmyoIysgkV+sOG38jiMGiPSMd2JYDpb7jp05CnHt1iib CfELLukollil5m7alwCgpJxjAOYiH6i1No2tX/Oce07lu5H8XcgCvYmSi+SZ2i2FHqqI DN2g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=HHwJf2xD; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id k4-20020aa7d8c4000000b004ad099e74b5si9161465eds.556.2023.02.27.08.27.51; Mon, 27 Feb 2023 08:28:14 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=HHwJf2xD; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230025AbjB0QJm (ORCPT + 99 others); Mon, 27 Feb 2023 11:09:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54446 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229568AbjB0QJl (ORCPT ); Mon, 27 Feb 2023 11:09:41 -0500 Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2E7D211FD for ; Mon, 27 Feb 2023 08:09:39 -0800 (PST) Received: by mail-ed1-x535.google.com with SMTP id h16so27867358edz.10 for ; Mon, 27 Feb 2023 08:09:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=oxey+7sqWvWOo5NrntHk/o4WUHBkJNfXPSn9nqQN0fs=; b=HHwJf2xDfskdyehybrfXa3iNb4BleyyCmiQEn9jMnpD8Is4KnVVks3Tr9FTTGJWLpl 3WteILDty7qTDao8BbnP4UvfmK2Z8nUNXuAva5KkZNSqpnaqpcDCg6pehpWsI+eUWbB0 pE/TjJbfX2TFM0hxL99aWxjrDz7iUK/mvOJ2/BFI5vJZx2+wR/IXJ8M2HD/XXmdq4G6Q TUH6p310rJkGgL5Hvwb9Igs8gvOvb/P68x3NlyRnLQo2oomikSP1h3Ewy0IEsb1nuLoT FFWtj7Rq+MYEcManvP35UfTI/67jIB5pjh8w/kgYY8bLEPYEmR37M4E6V862ixqFnizC kg/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=oxey+7sqWvWOo5NrntHk/o4WUHBkJNfXPSn9nqQN0fs=; b=cgO1CDabMk88z5AewJsKwMiNIGiWK7hjLCbyHQE88jCs8CnopqthlaBOL5EPGiZmLW izpwVTqiQaJA1J650IaKznW97rgmeB8uNo6HQMuHACzvbpJ0xLLbvf/fryBeDf9zviLV 0fRJnmPzAS290IbEc43gsCiI6PmeLpsyzrHgCWf0cyYNugUQW0yq+7RMht3Tka9GbNbs WP4zVR1mRPf9QjuPfAW4wke5cYf9u2+02d7Q5newhTzv4BH8hwvZKPu5eQDWvYnlawvQ cjpfGL9yezM/2qsjM8cqNUkE/CSfxI8QgZOqsHVP4qlu7WL+2EWmarePOSIKxR4gkQyq fprw== X-Gm-Message-State: AO0yUKXoJC424+M2gWw9S/8tWwBUGkhNaHtRF/FTz4VJRKFugjFASMB0 eLtedqL1de6RRbHzazXYfRo/tYwJX3jtqw== X-Received: by 2002:a17:906:c7c6:b0:8af:305b:76af with SMTP id dc6-20020a170906c7c600b008af305b76afmr35043976ejb.33.1677514178217; Mon, 27 Feb 2023 08:09:38 -0800 (PST) Received: from localhost.localdomain ([46.248.82.114]) by smtp.gmail.com with ESMTPSA id u20-20020a170906655400b008f2b0c6052csm3342899ejn.89.2023.02.27.08.09.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Feb 2023 08:09:37 -0800 (PST) From: Uros Bizjak To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Uros Bizjak , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Subject: [PATCH] x86/apic: Fix atomic update of offset in reserve_eilvt_offset Date: Mon, 27 Feb 2023 17:09:17 +0100 Message-Id: <20230227160917.107820-1-ubizjak@gmail.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759002277783819697?= X-GMAIL-MSGID: =?utf-8?q?1759002277783819697?= The detection of atomic update failure in reserve_eilvt_offset is not correct. The value, returned by atomic_cmpxchg should be compared to the old value from the location to be updated. If these two are the same, then atomic update succeeded and "eilvt_offsets[offset]" location is updated to "new" in an atomic way. Otherwise, the atomic update failed and it should be retried with the value from "eilvt_offsets[offset]" - exactly what atomic_try_cmpxchg does in a correct and more optimal way. Fixes: a68c439b1966c ("apic, x86: Check if EILVT APIC registers are available (AMD only)") Signed-off-by: Uros Bizjak Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" --- arch/x86/kernel/apic/apic.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 20d9a604da7c..770557110051 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -422,10 +422,9 @@ static unsigned int reserve_eilvt_offset(int offset, unsigned int new) if (vector && !eilvt_entry_is_changeable(vector, new)) /* may not change if vectors are different */ return rsvd; - rsvd = atomic_cmpxchg(&eilvt_offsets[offset], rsvd, new); - } while (rsvd != new); + } while (!atomic_try_cmpxchg(&eilvt_offsets[offset], &rsvd, new)); - rsvd &= ~APIC_EILVT_MASKED; + rsvd = new & ~APIC_EILVT_MASKED; if (rsvd && rsvd != vector) pr_info("LVT offset %d assigned for vector 0x%02x\n", offset, rsvd);