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 7F92EC433FE for ; Wed, 19 Oct 2022 13:27:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F0DAB6B0071; Wed, 19 Oct 2022 09:27:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EBF046B0073; Wed, 19 Oct 2022 09:27:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D5E996B0074; Wed, 19 Oct 2022 09:27:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id C7F7F6B0071 for ; Wed, 19 Oct 2022 09:27:55 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 9CDED1A0AF0 for ; Wed, 19 Oct 2022 13:27:55 +0000 (UTC) X-FDA: 80037776910.21.643DD7C Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by imf10.hostedemail.com (Postfix) with ESMTP id AE898C002C for ; Wed, 19 Oct 2022 13:27:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666186073; x=1697722073; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=maPvHabENdJbu0SifYloWSh+XeE9JeazxOD/pHHB/rU=; b=H9meGOIgd6O8IOPQdIf/Hk7CRVGy1DYWrcTzUogNOp08zwMdO9sEYKo8 rgUbkcGOnKgsCkkAKNZ0S8EjqoFringJoCf+Y9w6U0v91FuqvaoA8zfsg Euvo/YcvM4Y/dLM24lXx+EmLrOP3J82kzcl1Oky8WJsz2UiyQSKDLsGSK g2R2NuGtk5x9g957LlU/8m/UuFh/2CHIXx+RYRh6vpRAg21UBo93AHfLg fcjQJJSQl3HZmDecwl7DtZEHXKTvvqvdjoyKugHBV9XM0aii1uUci4dQN uakT9dJrMoDdhwPYV6jlNHWsKc+ACuccuHyD2Y9jmJ5IxdlPwJ9Ha+Sdr w==; X-IronPort-AV: E=McAfee;i="6500,9779,10505"; a="392709518" X-IronPort-AV: E=Sophos;i="5.95,196,1661842800"; d="scan'208";a="392709518" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2022 06:27:51 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10505"; a="624134706" X-IronPort-AV: E=Sophos;i="5.95,196,1661842800"; d="scan'208";a="624134706" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.193.75]) by orsmga007.jf.intel.com with ESMTP; 19 Oct 2022 06:27:39 -0700 Date: Wed, 19 Oct 2022 21:23:08 +0800 From: Chao Peng To: Sean Christopherson Cc: Fuad Tabba , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , Michael Roth , mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Subject: Re: [PATCH v8 5/8] KVM: Register/unregister the guest private memory regions Message-ID: <20221019132308.GA3496045@chaop.bj.intel.com> Reply-To: Chao Peng References: <20220915142913.2213336-1-chao.p.peng@linux.intel.com> <20220915142913.2213336-6-chao.p.peng@linux.intel.com> <20221012023516.GA3218049@chaop.bj.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666186074; h=from:from:sender:reply-to: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=/VGr7XxcUTjGAahlOxlCFYwyoIETEO/zXmUEz6sJnJ0=; b=P5sMWeYECb6C8ZpteVugLwlW2s4DG/wcPgOlvJUf2soTzrz6IHDtuy/fyoTDEKC3Umc8Hk OcIiFnYosxxToxMplkMmOBsdSZ2S2oqBFsysoqVr+Q3bj6LprgDsQ701OZU+jr3X1rXX9G I6siKAT8TXq/MyzoyaLmlm7CQqGTyP4= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=H9meGOIg; spf=none (imf10.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.43) smtp.mailfrom=chao.p.peng@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666186074; a=rsa-sha256; cv=none; b=X8QGYOi2O36pghjCxLNtJOd5DxBg1iAiXMFWJyhy3nT1RvNpZfG6Sc7utaFxShk7iLu2CT 7CnxCc4T3dXIu2YnF1fRrACN2Yfa6NFsjLuRCrUos8qXAUN01Hd0yQvcsBO28V/R7uKFds tLj+YT65Op0koW4EqZ5Ir/lZ8clsoP8= X-Rspamd-Server: rspam12 X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=H9meGOIg; spf=none (imf10.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 192.55.52.43) smtp.mailfrom=chao.p.peng@linux.intel.com; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none) X-Stat-Signature: oeeesrzs1pawr9riogdafrf1wpmwce4s X-Rspamd-Queue-Id: AE898C002C X-HE-Tag: 1666186073-902946 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 Mon, Oct 17, 2022 at 10:17:45PM +0000, Sean Christopherson wrote: > On Mon, Oct 17, 2022, Fuad Tabba wrote: > > Hi, > > > > > > > +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM > > > > > +#define KVM_MEM_ATTR_SHARED 0x0001 > > > > > +static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size, > > > > > + bool is_private) > > > > > +{ > > > > > > > > I wonder if this ioctl should be implemented as an arch-specific > > > > ioctl. In this patch it performs some actions that pKVM might not need > > > > or might want to do differently. > > > > > > I think it's doable. We can provide the mem_attr_array kind thing in > > > common code and let arch code decide to use it or not. Currently > > > mem_attr_array is defined in the struct kvm, if those bytes are > > > unnecessary for pKVM it can even be moved to arch definition, but that > > > also loses the potential code sharing for confidential usages in other > > > non-architectures, e.g. if ARM also supports such usage. Or it can be > > > provided through a different CONFIG_ instead of > > > CONFIG_HAVE_KVM_PRIVATE_MEM. > > > > This sounds good. Thank you. > > I like the idea of a separate Kconfig, e.g. CONFIG_KVM_GENERIC_PRIVATE_MEM or > something. I highly doubt there will be any non-x86 users for multiple years, > if ever, but it would allow testing the private memory stuff on ARM (and any other > non-x86 arch) without needing full pKVM support and with only minor KVM > modifications, e.g. the x86 support[*] to test UPM without TDX is shaping up to be > trivial. CONFIG_KVM_GENERIC_PRIVATE_MEM looks good to me. Thanks, Chao > > [*] https://lore.kernel.org/all/Y0mu1FKugNQG5T8K@google.com