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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 D3119C4338F for ; Tue, 10 Aug 2021 17:52:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5642A61058 for ; Tue, 10 Aug 2021 17:52:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5642A61058 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B43728D0005; Tue, 10 Aug 2021 13:52:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AF3658D0001; Tue, 10 Aug 2021 13:52:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A09C48D0005; Tue, 10 Aug 2021 13:52:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0140.hostedemail.com [216.40.44.140]) by kanga.kvack.org (Postfix) with ESMTP id 8AA608D0001 for ; Tue, 10 Aug 2021 13:52:10 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1EA9D1826B6A6 for ; Tue, 10 Aug 2021 17:52:10 +0000 (UTC) X-FDA: 78459914820.31.2414DA2 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by imf14.hostedemail.com (Postfix) with ESMTP id 20A28600B647 for ; Tue, 10 Aug 2021 17:52:08 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10072"; a="211848611" X-IronPort-AV: E=Sophos;i="5.84,310,1620716400"; d="scan'208";a="211848611" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2021 10:52:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,310,1620716400"; d="scan'208";a="570864967" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga004.jf.intel.com with ESMTP; 10 Aug 2021 10:52:01 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 833FBF9; Tue, 10 Aug 2021 20:51:44 +0300 (EEST) Date: Tue, 10 Aug 2021 20:51:44 +0300 From: "Kirill A. Shutemov" To: Dave Hansen Cc: "Kirill A. Shutemov" , Borislav Petkov , 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 , x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/5] x86: Impplement support for unaccepted memory Message-ID: <20210810175144.uqlddcicyrweqb4j@black.fi.intel.com> References: <20210810062626.1012-1-kirill.shutemov@linux.intel.com> <4b80289a-07a4-bf92-9946-b0a8afb27326@intel.com> <20210810151548.4exag5uj73bummsr@black.fi.intel.com> <82b8836f-a467-e5ff-08f3-704a85b9faa0@intel.com> <20210810173124.vzxpluaepdfe5aum@black.fi.intel.com> <51d9168c-ac14-0907-79b3-5d4dd46f92d6@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51d9168c-ac14-0907-79b3-5d4dd46f92d6@intel.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 20A28600B647 Authentication-Results: imf14.hostedemail.com; dkim=none; spf=none (imf14.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 192.55.52.93) smtp.mailfrom=kirill.shutemov@linux.intel.com; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none) X-Stat-Signature: dtw3mgtytosk8oiu8wrh8rexe7ab454q X-HE-Tag: 1628617928-164725 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 10, 2021 at 10:36:21AM -0700, Dave Hansen wrote: > > The difference is going to be substantially lower once we get it optimized > > properly. > > What does this mean? Is this future work in the kernel or somewhere in > the TDX hardware/firmware which will speed things up? Kernel has to be changed to accept memory in 2M and 1G chunks where possible. The interface exists and described in spec, but not yet used in guest kernel. It would cut hypercall overhead dramatically. It makes upfront memory accept more bearable and lowers latency of lazy memory accept. So I expect the gap being not 20x, but like 3-5x (which is still huge). -- Kirill A. Shutemov