From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from albireo.enyo.de (albireo.enyo.de [37.24.231.21]) by sourceware.org (Postfix) with ESMTPS id 7E144385801A; Sat, 27 Mar 2021 19:15:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 7E144385801A Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=deneb.enyo.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=fw@deneb.enyo.de Received: from [172.17.203.2] (port=37569 helo=deneb.enyo.de) by albireo.enyo.de ([172.17.140.2]) with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) id 1lQEPB-0005F1-VK; Sat, 27 Mar 2021 19:15:29 +0000 Received: from fw by deneb.enyo.de with local (Exim 4.92) (envelope-from ) id 1lQEPB-0006VW-Qx; Sat, 27 Mar 2021 20:15:29 +0100 From: Florian Weimer To: "H.J. Lu via Libc-alpha" Cc: "H.J. Lu" , Siddhesh Poyarekar Subject: Re: [PATCH] x86: Disable RTM on Skylake [BZ #27398] References: <20210327183417.3390361-1-hjl.tools@gmail.com> Date: Sat, 27 Mar 2021 20:15:29 +0100 In-Reply-To: <20210327183417.3390361-1-hjl.tools@gmail.com> (H. J. Lu via Libc-alpha's message of "Sat, 27 Mar 2021 11:34:17 -0700") Message-ID: <87mtuo76i6.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=-12.1 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 27 Mar 2021 19:15:33 -0000 * H. J. Lu via Libc-alpha: > Disable RTM explicitly on Skylake since CPUID may incorrectly report RTM > feature. > --- > sysdeps/x86/cpu-features.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c > index d7248cbb45..3641a48407 100644 > --- a/sysdeps/x86/cpu-features.c > +++ b/sysdeps/x86/cpu-features.c > @@ -518,6 +518,10 @@ init_cpu_features (struct cpu_features *cpu_features) > with stepping >= 4) to avoid TSX on kernels that weren't > updated with the latest microcode package (which disables > broken feature by default). */ > + case 0x8e: > + case 0x9e: > + /* Disable RTM explicitly on Skylake since CPUID may report > + RTM feature incorrectly [BZ #27398]. */ > CPU_FEATURE_UNSET (cpu_features, RTM); > break; > } Won't this affect the server parts as well? I'm not sure if that's what our users want. We need to report the kernel bug properly, it got stalled because we initially suspected it might be a security bug.