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=-7.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=no 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 0DED8C433ED for ; Thu, 13 May 2021 01:06:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC24C61264 for ; Thu, 13 May 2021 01:06:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234788AbhEMBH2 (ORCPT ); Wed, 12 May 2021 21:07:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234765AbhEMBH2 (ORCPT ); Wed, 12 May 2021 21:07:28 -0400 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D9EBC061574; Wed, 12 May 2021 18:06:19 -0700 (PDT) Received: by mail-pl1-x632.google.com with SMTP id n3so1352646plf.7; Wed, 12 May 2021 18:06:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=JdjLenGm8qjHYQsyQoKVaW3PTpEveC22o5czLzfvk6Y=; b=loq1VJUyP3/kDLOrzwSNufspWWWMh0fp2SKxkcsSBhXkowmGIIe77TWUY9162Gw0PX ORNhAADve2zXOpzqO3CA8NZHZdYMxO/gGRNmz01q2c6tWBEB/KZiJe+c31focjlL0Jst 9CHZOLVuvsuevl8pZ4MJT8/DrxVugQ1lNDdulks8XQU5cLN32VHNTWBJrtZoChrgGB1p 7kWPFmp/5oSbX5T3lm5SxBKfeFyewPToZuAeEgLznzYjMNyHkgxcLoRQ/nPV8P781Khz L9Z1xrEngA4cQcMcGeZF+Qvy1UvyT5l1ghSN237qfLb+BpT+DNkWy3L3z1sT6LYJ/EIG Tmhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=JdjLenGm8qjHYQsyQoKVaW3PTpEveC22o5czLzfvk6Y=; b=Lo6+0kCBAEkx5qnRIvJdr8aaWxEirlVQT6DG9xCUOdD55j9PDtUqiskzfCL/XebC8T Qh4Th3GuK1TPbxxEgPal2EH1Y569kccK1RKaY/m6S5p/zQudNPfiKKgHSOvmYusF7I5g XMxe6ClEO9IVAsSepTKu13shcXQLOpANs0v7o5dYgGfrJMsQqEaVUX30V9W2BLhzxFVj JUHkVWk6b85dPfoh62Z5Ot7uOK2BGIu2JmK5n/RKA5Hu64VtWOYm/1/oAHAW9LqKyQLf R5CMxIlJLlV1Ml5yHZpuIYRazObKdAgLW4jmWBH4mAyH1z+YRjS7Ht0pC1k/jYoLztAz imlA== X-Gm-Message-State: AOAM533T6O6iQ7r0nbOmpQ2g8OiR8oZStEf7kVBtVLwJJ7Rxp8GP0TUl z7v84c7n99mMA3roR6+MKXs= X-Google-Smtp-Source: ABdhPJzRlb5fpSedqGJZ1QVc911yW3TBNyDU55CHyi1sTZiBC+SzxoJ5Z0IGJ9dj6BjoJpxN4QQK0w== X-Received: by 2002:a17:902:7c91:b029:ed:5748:901e with SMTP id y17-20020a1709027c91b02900ed5748901emr37788961pll.27.1620867978613; Wed, 12 May 2021 18:06:18 -0700 (PDT) Received: from localhost ([203.87.99.126]) by smtp.gmail.com with ESMTPSA id d3sm792225pfn.141.2021.05.12.18.06.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 May 2021 18:06:17 -0700 (PDT) Date: Thu, 13 May 2021 11:06:14 +1000 From: Balbir Singh To: Thomas Gleixner Cc: Kees Cook , "mingo@redhat.com" , "linux-kernel@vger.kernel.org" , "peterz@infradead.org" , "torvalds@linux-foundation.org" , "jpoimboe@redhat.com" , "x86@kernel.org" , "tony.luck@intel.com" , "dave.hansen@intel.com" , "thomas.lendacky@amd.com" , "benh@kernel.crashing.org" , linux-hardening@vger.kernel.org Subject: Re: [PATCH v4 0/5] Next revision of the L1D flush patches Message-ID: <20210513010614.GH4236@balbir-desktop> References: <20210108121056.21940-1-sblbir@amazon.com> <202104081319.DAB1D817@keescook> <87y2d5tpjh.ffs@nanos.tec.linutronix.de> <87tunsofan.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87tunsofan.ffs@nanos.tec.linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Tue, Apr 27, 2021 at 12:24:16AM +0200, Thomas Gleixner wrote: > On Mon, Apr 26 2021 at 10:31, Thomas Gleixner wrote: > > On Thu, Apr 08 2021 at 13:23, Kees Cook wrote: > >> > >> I'd still really like to see this -- it's a big hammer, but that's the > >> point for cases where some new flaw appears and we can point to the > >> toolbox and say "you can mitigate it with this while you wait for new > >> kernel/CPU." > >> > >> Any further thoughts from x86 maintainers? This seems like it addressed > >> all of tglx's review comments. > > > > Sorry for dropping the ball on this. It's in my list of things to deal > > with. Starting to look at it now. > > So I went through the pile and for remorse I sat down and made the > tweaks I think are necessary myself. > > I've pushed out the result to > > git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git x86/l1dflush > Thank you I'll take a look and test it. > The only thing I did not address yet is that the documentation lacks any > mentioning of the SIGBUS mechanism which is invoked when a task which > asked for L1D flush protection ends up on a SMT sibling for whatever > reason. That's essential to have because it's part of the contract of > that prctl. IIRC I documented it, I'll double check. > > Balbir, can you please double check the result and prepare an updated > version from there? > > If you don't have cycles, please let me know. > I might have some cycles for testing and re-review. Thanks for all the hard work on this Balbir Singh.