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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78926C43334 for ; Wed, 15 Jun 2022 21:55:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348674AbiFOVzT (ORCPT ); Wed, 15 Jun 2022 17:55:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347869AbiFOVzR (ORCPT ); Wed, 15 Jun 2022 17:55:17 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC0EF3BBCB for ; Wed, 15 Jun 2022 14:55:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655330116; x=1686866116; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=2C9vYUhv5jL2K5xzRH45goeY7fn47lkvkQBHQ5F3nCE=; b=DmJqBheUUnVN2mhPBs24RslqFUtDWTwG/ep3/xwBEmT622ETCyIt1cZO VFpki4bWqbMj4WvjK0wUte4x5K4pX0st/ySL4HCBGqh7Vkaa/twNQ2ZuW fdqU1J6pUPg3PJaYIlqWKxeItVRS9R3Y2NjkKSV5UBD25G9cnTWUQOhpv pYvU9s3XWrtsnDFIh14gwT8gX+Y7q3NCdZ4ER3wNo4/wb3m27Rg1GUtiT p3cMwaBbeADee3HhON+p2/ZVM+BHpH4p/74wb0nsHi/4iZXfx2X7Vv7Hg 40aKAUf8Rw7lDM4qTIeUz9VO5JoERHM1LLGaPxWgBrKeegcPuy4LHFMKQ A==; X-IronPort-AV: E=McAfee;i="6400,9594,10379"; a="343068095" X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="343068095" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 14:55:13 -0700 X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="559385208" Received: from mjortiz-mobl.amr.corp.intel.com (HELO [10.212.185.241]) ([10.212.185.241]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 14:55:13 -0700 Message-ID: <1d190555-2bb1-e483-2405-e28ddabead07@intel.com> Date: Wed, 15 Jun 2022 14:55:13 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCHv4 3/3] x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page Content-Language: en-US To: "Kirill A. Shutemov" Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, luto@kernel.org, peterz@infradead.org, ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, sathyanarayanan.kuppuswamy@linux.intel.com, seanjc@google.com, thomas.lendacky@amd.com, x86@kernel.org References: <20220614120135.14812-1-kirill.shutemov@linux.intel.com> <20220614120135.14812-4-kirill.shutemov@linux.intel.com> <051fd468-11e6-308b-66c8-4de16ff80deb@intel.com> <20220615171042.oeumb3vs3ttu4rvd@black.fi.intel.com> From: Dave Hansen In-Reply-To: <20220615171042.oeumb3vs3ttu4rvd@black.fi.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/15/22 10:10, Kirill A. Shutemov wrote: >> I thought this whole exercise was kicked off by hitting this in testing. >> Am I remembering this wrong? >> >>> https://lore.kernel.org/all/20220517153444.11195-10-kirill.shutemov@linux.intel.com/ >> Says: >> >>> This is an actual, real-world problem which was discovered during TDX >>> testing. >> Or were you considering this a different problem somehow? > They are different. > > The patch by the link addresses issue of load_unaligned_zeropad() stepping > onto unaccepted memory. This was triggered in practice. OK, so we've got two problems both triggered by load_unaligned_zeropad(), but where the fixes are different. We actually hit the "unaccepted memory one" in testing, but that made us think about other problems in the area and that's where this one came up.