From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD80819644B for ; Sun, 23 Mar 2025 18:15:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742753715; cv=none; b=mvW41ji8hBM/TcxBeUbSDLjVB1qMtlxQclRDLLvMj5BV2XiHhoQEMWOODS2cnS5ZfXhwHz05Q5wpRSpti5agOtWzfM4gvGZtfgpDbFroZlXYOwgQ7Q1/N15a3bJfVJxD5LFnbxvzOLT+aPwaE3TGPCWTuwwDfMQiqqv91k3FjRg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742753715; c=relaxed/simple; bh=gVA3JCX04/vCsbB4HcDlaTmKquk3ta8AlG6E4Wkbm/I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EpvJgUe53c4BMaqPGy1nnTbp8h7BygrgPUSF31YuaU0pst8ouTQaCMCG1/7CKjmAYNyNJam/K5ijeJYNKFOVABidWsN8ox8WhWNTe9TcA3a7GvHmxCd70mGyfWY3urCVR567A7t0QVGKSzldGftEImrgzbda6h5eJX67OrBnmfU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=XkNggL/t; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="XkNggL/t" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 24B2B40E0196; Sun, 23 Mar 2025 18:15:03 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id RFP44gPZprFw; Sun, 23 Mar 2025 18:14:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1742753699; bh=PIIWjnrfA984bOqJi5eOt7MWu8DHV+mIsqq/VA99BJg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XkNggL/t5g8IniNgywso8rgSv21YakXchEAZgz2CaVKWw1GJQHnORBKypn7jwBeXO gFzDqVgWerFAB+C/mgw6kIJ+WXOAZ+yYD8TBLS+BEA+CtkO7L3OVaf50Am5kyOtDwV cXnAWVA0ggHpUueks5zQSIY85jc8AlQBbteozYBHivSyEHn/eeYC0VzS+ybIs6KtL3 UGcwpSejJcBSlySF5C+RMKeYxx24jBbmMG3aZkIbaSgFldhx8kuXMlPPiOL6ZVqy0Z x3wMuC2y0ZRXY4z83mQ7jNC/OtA497BwhsvbDAL40dhV7hGlhUtG6+EuXKP0T/782i HrXKQVyg04TxdduCJY8svlusqtjP7N10MgXIr08FcQ35jLUeCg7zFrM1pmXcmQLsHe KDzfYPCyIcbapaLf/gcHGta5Y3rqfRPgkG/s8P61MIuC+WsZoD1sscliSRMJpQuQ7Q KV4fMpf9IUNu/womUnZ5m2BbCPwPQiSigvcxcWOkcYKodeRq7+mQDGp8DY01oOyC5J KXpeneSH/cph5FZjp/QbSDpFejWaG2otdB2VjdrdEw2yFK3WqUqEU1fIwgk2TOOgE5 JV1yEQAUBH9zEjFpTaFh8gwL8sBmIqqtyA0Ab4u1+PFNAgOAbu/MBxvxEnlbI/H3Ds 9AjhlqdwO0kreqacjeYzZhIQ= Received: from zn.tnic (pd95303ce.dip0.t-ipconnect.de [217.83.3.206]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 4CEC040E01FF; Sun, 23 Mar 2025 18:14:50 +0000 (UTC) Date: Sun, 23 Mar 2025 19:14:44 +0100 From: Borislav Petkov To: "Guilherme G. Piccoli" Cc: Thomas Gleixner , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, dave.hansen@linux.intel.com, kernel@gpiccoli.net, kernel-dev@igalia.com Subject: Re: [PATCH] x86/tsc: Add debugfs entry to mark TSC as unstable after boot Message-ID: <20250323181444.GCZ-BPlCAhtO7AIsS7@fat_crate.local> References: <20250226132733.58327-1-gpiccoli@igalia.com> <1238b1d0-275c-9117-a2e3-5e7684404980@igalia.com> <87iko213qo.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Sun, Mar 23, 2025 at 02:53:05PM -0300, Guilherme G. Piccoli wrote: > But what about AMD systems? Even the modern ones apparently lack > TSC_ADJUST - or is it changing recently? Yes, it is. > Checking TSC code, it is full of checks "if Intel" as well, like in > native calibration. Our issue is present on AMD and my impression is > that, in this respect, these systems are way more unstable (from TSC > perspective) than the ones having TSC_ADJUST. The only one I know of is a Zen2 laptop where BIOS botches a perfectly fine TSC because those BIOS programmers are soo smart. If you know of other cases, where are those bug reports? Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette