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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 8D04AECDE3B for ; Wed, 17 Oct 2018 22:21:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4CA0D2087A for ; Wed, 17 Oct 2018 22:21:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4CA0D2087A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727549AbeJRGTA (ORCPT ); Thu, 18 Oct 2018 02:19:00 -0400 Received: from mga11.intel.com ([192.55.52.93]:56105 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727309AbeJRGS7 (ORCPT ); Thu, 18 Oct 2018 02:18:59 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Oct 2018 15:21:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,393,1534834800"; d="asc'?scan'208";a="101106686" Received: from smamidi-mobl.amr.corp.intel.com (HELO [10.251.27.65]) ([10.251.27.65]) by orsmga002.jf.intel.com with ESMTP; 17 Oct 2018 15:21:13 -0700 Subject: Re: l1tf: Kernel suggests I throw away third of my memory. I'd rather not To: Pavel Machek , Michal Hocko References: <20181017105610.GA4260@amd> <20181017111544.GO18839@dhcp22.suse.cz> <20181017113226.GA5176@amd> Cc: vbabka@suse.cz, hpa@zytor.com, torvalds@linux-foundation.org, ak@linux.intel.com, kernel list , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de From: Dave Hansen Openpgp: preference=signencrypt Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzShEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gPGRhdmVAc3I3MS5uZXQ+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAUCTo3k0QIZAQAKCRBoNZUwcMmSsMO2D/421Xg8pimb9mPzM5N7khT0 2MCnaGssU1T59YPE25kYdx2HntwdO0JA27Wn9xx5zYijOe6B21ufrvsyv42auCO85+oFJWfE K2R/IpLle09GDx5tcEmMAHX6KSxpHmGuJmUPibHVbfep2aCh9lKaDqQR07gXXWK5/yU1Dx0r VVFRaHTasp9fZ9AmY4K9/BSA3VkQ8v3OrxNty3OdsrmTTzO91YszpdbjjEFZK53zXy6tUD2d e1i0kBBS6NLAAsqEtneplz88T/v7MpLmpY30N9gQU3QyRC50jJ7LU9RazMjUQY1WohVsR56d ORqFxS8ChhyJs7BI34vQusYHDTp6PnZHUppb9WIzjeWlC7Jc8lSBDlEWodmqQQgp5+6AfhTD kDv1a+W5+ncq+Uo63WHRiCPuyt4di4/0zo28RVcjtzlGBZtmz2EIC3vUfmoZbO/Gn6EKbYAn rzz3iU/JWV8DwQ+sZSGu0HmvYMt6t5SmqWQo/hyHtA7uF5Wxtu1lCgolSQw4t49ZuOyOnQi5 f8R3nE7lpVCSF1TT+h8kMvFPv3VG7KunyjHr3sEptYxQs4VRxqeirSuyBv1TyxT+LdTm6j4a mulOWf+YtFRAgIYyyN5YOepDEBv4LUM8Tz98lZiNMlFyRMNrsLV6Pv6SxhrMxbT6TNVS5D+6 UorTLotDZKp5+M7BTQRUY85qARAAsgMW71BIXRgxjYNCYQ3Xs8k3TfAvQRbHccky50h99TUY sqdULbsb3KhmY29raw1bgmyM0a4DGS1YKN7qazCDsdQlxIJp9t2YYdBKXVRzPCCsfWe1dK/q 66UVhRPP8EGZ4CmFYuPTxqGY+dGRInxCeap/xzbKdvmPm01Iw3YFjAE4PQ4hTMr/H76KoDbD cq62U50oKC83ca/PRRh2QqEqACvIH4BR7jueAZSPEDnzwxvVgzyeuhwqHY05QRK/wsKuhq7s UuYtmN92Fasbxbw2tbVLZfoidklikvZAmotg0dwcFTjSRGEg0Gr3p/xBzJWNavFZZ95Rj7Et db0lCt0HDSY5q4GMR+SrFbH+jzUY/ZqfGdZCBqo0cdPPp58krVgtIGR+ja2Mkva6ah94/oQN lnCOw3udS+Eb/aRcM6detZr7XOngvxsWolBrhwTQFT9D2NH6ryAuvKd6yyAFt3/e7r+HHtkU kOy27D7IpjngqP+b4EumELI/NxPgIqT69PQmo9IZaI/oRaKorYnDaZrMXViqDrFdD37XELwQ gmLoSm2VfbOYY7fap/AhPOgOYOSqg3/Nxcapv71yoBzRRxOc4FxmZ65mn+q3rEM27yRztBW9 AnCKIc66T2i92HqXCw6AgoBJRjBkI3QnEkPgohQkZdAb8o9WGVKpfmZKbYBo4pEAEQEAAcLB XwQYAQIACQUCVGPOagIbDAAKCRBoNZUwcMmSsJeCEACCh7P/aaOLKWQxcnw47p4phIVR6pVL e4IEdR7Jf7ZL00s3vKSNT+nRqdl1ugJx9Ymsp8kXKMk9GSfmZpuMQB9c6io1qZc6nW/3TtvK pNGz7KPPtaDzvKA4S5tfrWPnDr7n15AU5vsIZvgMjU42gkbemkjJwP0B1RkifIK60yQqAAlT YZ14P0dIPdIPIlfEPiAWcg5BtLQU4Wg3cNQdpWrCJ1E3m/RIlXy/2Y3YOVVohfSy+4kvvYU3 lXUdPb04UPw4VWwjcVZPg7cgR7Izion61bGHqVqURgSALt2yvHl7cr68NYoFkzbNsGsye9ft M9ozM23JSgMkRylPSXTeh5JIK9pz2+etco3AfLCKtaRVysjvpysukmWMTrx8QnI5Nn5MOlJj 1Ov4/50JY9pXzgIDVSrgy6LYSMc4vKZ3QfCY7ipLRORyalFDF3j5AGCMRENJjHPD6O7bl3Xo 4DzMID+8eucbXxKiNEbs21IqBZbbKdY1GkcEGTE7AnkA3Y6YB7I/j9mQ3hCgm5muJuhM/2Fr OPsw5tV/LmQ5GXH0JQ/TZXWygyRFyyI2FqNTx4WHqUn3yFj8rwTAU1tluRUYyeLy0ayUlKBH ybj0N71vWO936MqP6haFERzuPAIpxj2ezwu0xb1GjTk4ynna6h5GjnKgdfOWoRtoWndMZxbA z5cecg== Message-ID: Date: Wed, 17 Oct 2018 15:21:00 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181017113226.GA5176@amd> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="5kEwjPTDEla28jY3WucQ7YCtXcSaUYnZl" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --5kEwjPTDEla28jY3WucQ7YCtXcSaUYnZl Content-Type: multipart/mixed; boundary="vB5Hp7dXOXe2ZNK0dlRv2724OM2e7QhBr"; protected-headers="v1" From: Dave Hansen To: Pavel Machek , Michal Hocko Cc: vbabka@suse.cz, hpa@zytor.com, torvalds@linux-foundation.org, ak@linux.intel.com, kernel list , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de Message-ID: Subject: Re: l1tf: Kernel suggests I throw away third of my memory. I'd rather not References: <20181017105610.GA4260@amd> <20181017111544.GO18839@dhcp22.suse.cz> <20181017113226.GA5176@amd> In-Reply-To: <20181017113226.GA5176@amd> --vB5Hp7dXOXe2ZNK0dlRv2724OM2e7QhBr Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 10/17/2018 04:32 AM, Pavel Machek wrote: >> Well, that depends. Do you care about PROT_NONE attacks as well? If no= t >> then no-swap would help you. But even then no-swap is rather theoretic= al >> attack on a physical host unless you allow an arbitrary swapout to a >> malicious user (e.g. allow a user controlled memcg hard limit that wou= ld >> cause excessive local swapouts). > PROT_NONE attack.. aha, so kernel stores not only information about > swapped-out pages but also about file-backed pages that are currently > not present? Hmm. That makes it more complex :-(.=20 There are also migration PTE entries that are "swap-like". They can exist even if you swapoff -a. Can we do better? Sure. I think we'd all be happy to review patches that improve the situation if folks have simple ideas for improvement. --vB5Hp7dXOXe2ZNK0dlRv2724OM2e7QhBr-- --5kEwjPTDEla28jY3WucQ7YCtXcSaUYnZl Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJbx7XZAAoJEGg1lTBwyZKwNpEP/jTj8Xol1J0WWuh7Rnc6LeSA u0AnP0/VQ4ZfebGCD7WUNQqHSOkMRwdCXEhFzvCgA6s+x9xtEd1mmXqelgh1W82G H2qNnvcXxUn7pyknz7eLFC9W4FMv9TKNM6YhOMlvHr4Are++JW7r9DKjPZVGeyES uycBhNfKm0h7E6+e9pILY8HwEXKajnbkYQWppi5nqZSFJYtnE5gd8MRybQwd+62j y43ppErL8Mod5y73sVdsl3vWAhHTLV23WAivm4JPxRgtJh5LTTGag5SuOUcjuprh uGgr6PCSU3AwcZUzUfNaFSP3/9TqkfXVVjST4RGLAhhMEOwW9J3mJ73U0yRCcJ6/ QuR3oaOZbycm8I2y56pQmP9sWjSdYPEU8krwPO6XEocmzBLM17oJB682QHXDX3z+ YPDPjxGiKwZDY9fas3dXBZ/sAFTuW/LXDO+GU3p8hiGpSs6b7OHI4+14jOpabSWo b/WcDlzCsYv1VHw5UqdewmOQ5lmjPvdbZ6FsfcJMGiGtg82qJi7qROwq9iOtDyQa 1uuP1iiUEypkmbR02JFZ7jUa6upcNwbFISyZCMPhQ9GJPWYpvY4SGAsKdZ7Ev2sV wDOptFK25RFkKaGvNhClGrsEjuYdC5ziHTkmBG3XTls8SAGlqY784zbSWmZe/vLt t/SRqig9U72k0YtbvdFY =w4KN -----END PGP SIGNATURE----- --5kEwjPTDEla28jY3WucQ7YCtXcSaUYnZl--