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 7F673C433EF for ; Wed, 15 Jun 2022 22:43:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347927AbiFOWnF (ORCPT ); Wed, 15 Jun 2022 18:43:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237675AbiFOWnE (ORCPT ); Wed, 15 Jun 2022 18:43:04 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A7DC3B3E3 for ; Wed, 15 Jun 2022 15:43:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655332983; x=1686868983; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=GOkKIF1zj4v3HvWCe1Wl62pksKaDezBETS9z2NLNPsw=; b=dpSO5bwBCez9tzCVvujrP//3OAFBjTUB7739GI0erLcboqdmjLlnwmBD +0o4+XUjAdCtpv1WtxddWv9erwP9MI+IerP/UAhYAdFlMQ4ls4iSGDqgz Zgskd/s8BXRF13MDxenibpN1tmDfVDVkh3CuekCI2MPOhRybDjKicHcc0 AV3IScUZDcSXrCLMjsGBzeZifJTr35aWZs0KJeCt+ooq4qxdeeJeKWEyK uabsyn3UpzGm8N3g/3XGi8YHiKv0316j4XwPKJt8c0i99D4UfBHur8ex4 u7mDni0GLXgsD89BTTeb/6Udn/9Qx/HpUoS2q+kKohBPT2Vxt+T3VJBLO g==; X-IronPort-AV: E=McAfee;i="6400,9594,10379"; a="304554766" X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="304554766" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 15:43:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="618667193" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga001.jf.intel.com with ESMTP; 15 Jun 2022 15:42:59 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id BA860109; Thu, 16 Jun 2022 01:43:03 +0300 (EEST) Date: Thu, 16 Jun 2022 01:43:03 +0300 From: "Kirill A. Shutemov" To: Dave Hansen 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 Subject: Re: [PATCHv4 3/3] x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page Message-ID: <20220615224303.el4qtowheu2rgpdn@black.fi.intel.com> 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> <1d190555-2bb1-e483-2405-e28ddabead07@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1d190555-2bb1-e483-2405-e28ddabead07@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 15, 2022 at 02:55:13PM -0700, Dave Hansen wrote: > 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. I will reword it like this: The issue was discovered by analysis after triggering other issue with load_unaligned_zeropad(). Works for you? -- Kirill A. Shutemov