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=-3.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT 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 DBBDCC282C0 for ; Wed, 23 Jan 2019 17:50:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0F81218A2 for ; Wed, 23 Jan 2019 17:50:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="YztifqOv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726249AbfAWRuw (ORCPT ); Wed, 23 Jan 2019 12:50:52 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:44222 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725896AbfAWRuv (ORCPT ); Wed, 23 Jan 2019 12:50:51 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id x0NHiOua103823; Wed, 23 Jan 2019 17:50:47 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=0xfOsHv/8cfiH5wzoIyStx5mdpM3wYHUpLbBPkuYiWI=; b=YztifqOvpx687Th1UeTaVULm6eZyqGe1LKqV7YgTkSX2y6A98VRyFqRe83yREoUE11xI 3HEWa1jcv/F/GTV7yypeAIng/2dcVLMLHIw4NWccbAf/K/Z34D5ge0o5uNNnMX5BEn1c u2wZbnfHWMMV1n+bSnTdoPT4GKLreLbHx/jADj8jJIvNHifwhbwBsfxAhxb+zel/A4Zz 3uYKOtA5uKJygFXtw0Ou4PIMwuV2dbVOgXSnTPsfbPlfiWYou8iYcgpMgHpBxtKlXs1I KZFO6bDODlX79JGrkriHA37S/vvOShiW5NDpyKEA52VTPZDHmjK8PrEAAqvk/GR5kp4/ Kg== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2130.oracle.com with ESMTP id 2q3uauuf4g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 23 Jan 2019 17:50:47 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x0NHofAp020808 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 23 Jan 2019 17:50:41 GMT Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x0NHof1Q004855; Wed, 23 Jan 2019 17:50:41 GMT Received: from Konrads-MacBook-Pro.local (/75.104.64.133) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 23 Jan 2019 09:50:41 -0800 Date: Wed, 23 Jan 2019 12:50:18 -0500 From: Konrad Rzeszutek Wilk To: KarimAllah Ahmed Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, rkrcmar@redhat.com Subject: Re: [PATCH v5 04/13] KVM: Introduce a new guest mapping API Message-ID: <20190123175014.GK19289@Konrads-MacBook-Pro.local> References: <1547026933-31226-1-git-send-email-karahmed@amazon.de> <1547026933-31226-5-git-send-email-karahmed@amazon.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1547026933-31226-5-git-send-email-karahmed@amazon.de> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9145 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=665 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901230131 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > + if (dirty) > + kvm_release_pfn_dirty(map->pfn); > + else > + kvm_release_pfn_clean(map->pfn); > + map->hva = NULL; I keep on having this gnawing feeling that we MUST set map->page to NULL. That is I can see how it is not needed if you are using 'map' and 'unmap' together - for that we are good. But what I am worried is that some one unmaps it .. and instead of checking map->hva they end up checking map->page and think the page is mapped. Would you be OK adding that extra statement just as a fail-safe mechanism in case someones misues the APIs?