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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92100C25B07 for ; Tue, 9 Aug 2022 11:51:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C0CB66B0073; Tue, 9 Aug 2022 07:51:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BBB538E0001; Tue, 9 Aug 2022 07:51:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A5B2D6B0075; Tue, 9 Aug 2022 07:51:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 985106B0073 for ; Tue, 9 Aug 2022 07:51:38 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 6814EAB566 for ; Tue, 9 Aug 2022 11:51:38 +0000 (UTC) X-FDA: 79779889476.03.38A4B3C Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf17.hostedemail.com (Postfix) with ESMTP id 3530E4006C for ; Tue, 9 Aug 2022 11:51:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660045897; x=1691581897; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=eDgcat5jz2gPDhDhIYJ5SQ3oYmJhT05bUBFYCgTExWE=; b=hy4spaFW+jEQ5Em2ldgzHeK7+V4pfn4ba6WyUadMbz+Xp08c1VpBVQXv t5waImDrFsQuEf+1GK+ohUKKpe9rXADxiijLKgqlV08kY+moBwbhPZ9hX 4QnvuItwzf11E7Ku4C55yMis1CN7I+vCVrax3PxND4UoA137ecpdU5XvO pxzWOgHzkLLYtqz5eAJYwun4cXbhVwgAJYPgIRJxXdz2ZWDse3f58g3p0 IW6SkOEdknZfhmuY3aqSS3AZFmeXmQX1k13+3s/tNJ4Q0biqaFGIp00i5 qQ4kSYQ+EOOYasE/owEaTCAt2ZpzjxomGBPeSPzBcOuRtt3Dqn6BO8ZSK Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10433"; a="270590185" X-IronPort-AV: E=Sophos;i="5.93,224,1654585200"; d="scan'208";a="270590185" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Aug 2022 04:51:35 -0700 X-IronPort-AV: E=Sophos;i="5.93,224,1654585200"; d="scan'208";a="747012231" Received: from labukara-mobl.ger.corp.intel.com (HELO box.shutemov.name) ([10.251.214.212]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Aug 2022 04:51:29 -0700 Received: by box.shutemov.name (Postfix, from userid 1000) id 7CAAF103886; Tue, 9 Aug 2022 14:54:27 +0300 (+03) Date: Tue, 9 Aug 2022 14:54:27 +0300 From: "Kirill A. Shutemov" To: Ard Biesheuvel Cc: Dave Hansen , Marc Orr , Borislav Petkov , Dionna Amalie Glaze , Peter Gonda , Andy Lutomirski , Sean Christopherson , Andrew Morton , Joerg Roedel , Andi Kleen , Kuppuswamy Sathyanarayanan , David Rientjes , Vlastimil Babka , Tom Lendacky , Thomas Gleixner , Peter Zijlstra , Paolo Bonzini , Ingo Molnar , Varad Gautam , Dario Faggioli , Mike Rapoport , David Hildenbrand , Marcelo Cerri , tim.gardner@canonical.com, Khalid ElMously , philip.cox@canonical.com, the arch/x86 maintainers , Linux Memory Management List , linux-coco@lists.linux.dev, linux-efi , LKML , "Yao, Jiewen" Subject: Re: [PATCHv7 00/14] mm, x86/cc: Implement support for unaccepted memory Message-ID: <20220809115427.bmkbap434oupinq2@box.shutemov.name> References: <22d54786-bc12-ecc5-2b37-cbaa56090aa8@intel.com> <20220809111436.kudwg2nprnnsfvuh@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660045897; a=rsa-sha256; cv=none; b=pybH0eVL3jZxLALOjm74rSYZuJzxOOb4hLF5408mrwgVuBIw89cQziSMZ+g/3a+1eFOkG5 32AENSGLJns9uC4yCgmXG7U+6sNECBrQZ3ehscSjUDzvuqNL72fv1zBfmCnekLTDdMEsMS 2N40YrSDyUTnwzHaWixgth695bNV9hA= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=hy4spaFW; spf=none (imf17.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 192.55.52.136) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660045897; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=6ZguVBUcHzk77hs/Ai88TJWCfpaz6sSIAqzkZu9LLtA=; b=gk47/EfNtexbJw4BuCkLeowuL1OnFod5YwdATsL0jLI91s/E5G4Y9u7VKohIloWpkmif1N L3JxI5KtFxwe2+/mD9JSlRg9WYY7DQQ4Z/pnYuOzca5YaYc18WviuSguxY9ZtbMORiPfGr s29Qo+4EJZRIjpTUkf9Ynj+le+TK6lg= X-Rspamd-Queue-Id: 3530E4006C Authentication-Results: imf17.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=hy4spaFW; spf=none (imf17.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 192.55.52.136) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: qtn7ke6rdnu5ds1ymu46um8sst4o5o4u X-HE-Tag: 1660045896-152204 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Aug 09, 2022 at 01:36:00PM +0200, Ard Biesheuvel wrote: > On Tue, 9 Aug 2022 at 13:11, Kirill A. Shutemov > wrote: > > > > On Sat, Jul 23, 2022 at 01:14:07PM +0200, Ard Biesheuvel wrote: > > > On Thu, 21 Jul 2022 at 19:13, Dave Hansen wrote: > > > > > > > > On 7/19/22 17:26, Marc Orr wrote: > > > > > - Dave's suggestion to "2. Boot some intermediate thing like a > > > > > bootloader that does acceptance ..." is pretty clever! So if upstream > > > > > thinks this FW-kernel negotiation is not a good direction, maybe we > > > > > (Google) can pursue this idea to avoid introducing yet another tag on > > > > > our images. > > > > > > > > I'm obviously speaking only for myself here and not for "upstream" as a > > > > whole, but I clearly don't like the FW/kernel negotiation thing. It's a > > > > permanent pain in our necks to solve a very temporary problem. > > > > > > EFI is basically our existing embodiment of this fw/kernel negotiation > > > thing, and iff we need it, I have no objection to using it for this > > > purpose, i.e., to allow the firmware to infer whether or not it should > > > accept all available memory on behalf of the OS before exiting boot > > > services. But if we don't need this, even better. > > > > FW/kernel negotiation does not work if there's a boot loader in the middle > > that does ExitBootServices(). By the time kernel can announce if it > > supports unaccepted memory there's nobody to announce to. > > > > Why would you want to support such bootloaders for TDX anyway? TDX > heavily relies on measured boot abstractions and other things that are > heavily tied to firmware. I don't understand it either. And, yet, there's demand for it. -- Kiryl Shutsemau / Kirill A. Shutemov