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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B00D1C433B4 for ; Fri, 30 Apr 2021 05:23:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E00861434 for ; Fri, 30 Apr 2021 05:23:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230132AbhD3FYL (ORCPT ); Fri, 30 Apr 2021 01:24:11 -0400 Received: from mga05.intel.com ([192.55.52.43]:54053 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230085AbhD3FYJ (ORCPT ); Fri, 30 Apr 2021 01:24:09 -0400 IronPort-SDR: YoYAlgmiRhSYUwZXsiO/g7VnOoirSKSzSd5ka8lav05m7ZXUncZz82QxjVj8Yk16+S/edrCoBP 4armm7Z31YAg== X-IronPort-AV: E=McAfee;i="6200,9189,9969"; a="282543268" X-IronPort-AV: E=Sophos;i="5.82,260,1613462400"; d="scan'208";a="282543268" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2021 22:23:18 -0700 IronPort-SDR: APR3BpjXAr3DUNOrnyYgzaB1XLIscEEqLdhTqxozXLMjODMjMn0P0Kb1punqxqjPCExtHaQka/ rEbSOh72z+hg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,260,1613462400"; d="scan'208";a="527506049" Received: from clx-ap-likexu.sh.intel.com ([10.239.48.108]) by fmsmga001.fm.intel.com with ESMTP; 29 Apr 2021 22:23:15 -0700 From: Like Xu To: Peter Zijlstra Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-kernel@vger.kernel.org, Kan Liang , Borislav Petkov , seanjc@google.com, x86@kernel.org, Like Xu Subject: [PATCH v2 1/2] perf/x86: Skip checking if 0x0 MSR exists for guest Arch LBR Date: Fri, 30 Apr 2021 13:22:46 +0800 Message-Id: <20210430052247.3079672-1-like.xu@linux.intel.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The Architecture LBR does not have MSR_LBR_TOS (0x000001c9). In a guest that should support Architecture LBR, check_msr() will be a non-related check for the architecture MSR 0x0 (IA32_P5_MC_ADDR) that is also not supported by KVM. The failure will cause x86_pmu.lbr_nr = 0, thereby preventing the initialization of the guest Arch LBR. Fix it by avoiding this extraneous check in intel_pmu_init() for Arch LBR. Fixes: 47125db27e47 ("perf/x86/intel/lbr: Support Architectural LBR") Signed-off-by: Like Xu --- v1->v2 Changelog: - Avoid checking unrelated Architecture MSR 0x0 in a simple way arch/x86/events/intel/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 5272f349dca2..456aa6ffd9a1 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -6250,7 +6250,8 @@ __init int intel_pmu_init(void) * Check all LBT MSR here. * Disable LBR access if any LBR MSRs can not be accessed. */ - if (x86_pmu.lbr_nr && !check_msr(x86_pmu.lbr_tos, 0x3UL)) + if (x86_pmu.lbr_nr && !static_cpu_has(X86_FEATURE_ARCH_LBR) && + !check_msr(x86_pmu.lbr_tos, 0x3UL)) x86_pmu.lbr_nr = 0; for (i = 0; i < x86_pmu.lbr_nr; i++) { if (!(check_msr(x86_pmu.lbr_from + i, 0xffffUL) && -- 2.30.2