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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2C5E0C433F5 for ; Mon, 30 May 2022 12:04:51 +0000 (UTC) Received: from localhost ([::1]:58236 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nve8e-0006oE-D7 for qemu-devel@archiver.kernel.org; Mon, 30 May 2022 08:04:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36714) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nve3M-0008I1-7e for qemu-devel@nongnu.org; Mon, 30 May 2022 07:59:20 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:32774) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nve3J-00072n-OL for qemu-devel@nongnu.org; Mon, 30 May 2022 07:59:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1653911956; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xEV8sKFUdTUM3AL/I32tWpMjVPSfdad9VzF2DtI+nqM=; b=TWdMzjJnXza2b6U2+GZmPvzd0z46tBJB7+/qk2/d6m9ZYM7v0iUrsiNvf009Y5gd7T34E3 elDzD7fVKUUrDlJqS1HI+3AkK59KbU62AHKNG0QljPjIlV+m/DWAq5pMXWlAepA9kAK1m5 toG/aAepp3mj/YRcvc2D6xqp6fNblXE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-66-Gwz_03lfNHyfOE_hXCPuzQ-1; Mon, 30 May 2022 07:59:10 -0400 X-MC-Unique: Gwz_03lfNHyfOE_hXCPuzQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 190ED80B70A; Mon, 30 May 2022 11:59:10 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.39.192.41]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D3B9F40CFD0A; Mon, 30 May 2022 11:59:09 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 557A0180039F; Mon, 30 May 2022 13:59:08 +0200 (CEST) Date: Mon, 30 May 2022 13:59:08 +0200 From: Gerd Hoffmann To: Xiaoyao Li Cc: Isaku Yamahata , Paolo Bonzini , isaku.yamahata@intel.com, Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Richard Henderson , "Michael S . Tsirkin" , Marcel Apfelbaum , Cornelia Huck , Marcelo Tosatti , Laszlo Ersek , Eric Blake , Connor Kuehl , erdemaktas@google.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, seanjc@google.com Subject: Re: [RFC PATCH v4 22/36] i386/tdx: Track RAM entries for TDX VM Message-ID: <20220530115908.lcb6xegu4arfsqux@sirius.home.kraxel.org> References: <20220512031803.3315890-1-xiaoyao.li@intel.com> <20220512031803.3315890-23-xiaoyao.li@intel.com> <20220524073729.xkk6s4tjkzm77wwz@sirius.home.kraxel.org> <5e457e0b-dc23-9e5b-de89-0b137e2baf7f@intel.com> <20220526184826.GA3413287@ls.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kraxel@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi, > > tdx_add_ram_entry() increments tdx_guest->nr_ram_entries. I think it's worth > > for comments why this is safe regarding to this for-loop. > > The for-loop is to find the valid existing RAM entry (from E820 table). > It will update the RAM entry and increment tdx_guest->nr_ram_entries when > the initial RAM entry needs to be split. However, once find, the for-loop is > certainly stopped since it returns unconditionally. Add a comment saying so would be good. Or move the code block doing the update out of the loop. That will likewise make clear that finding the entry which must be updated is the only purpose of the loop. take care, Gerd