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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 4221AC433DB for ; Mon, 11 Jan 2021 22:12:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F215F22D00 for ; Mon, 11 Jan 2021 22:12:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389532AbhAKWMt (ORCPT ); Mon, 11 Jan 2021 17:12:49 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:35456 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726945AbhAKWMs (ORCPT ); Mon, 11 Jan 2021 17:12:48 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10BM9g6t000777; Mon, 11 Jan 2021 22:11:58 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2020-01-29; bh=qKII6CRwHxF6zi5JdH7+fTS9ebZYq9tFI4FIuyAD8ws=; b=L+q/q2onFVPovRvpx2VhhSK2tW9y/BHHSBokxogqmEDwiyonDpAuuxL3VKyaD/rqybVe uPWLv9FC5vApFJWnXlH8ZM+nKFwNvhXkiLj5daTyhF4YrJezCl8dUVcUntSXXkSavUdC /QaRa/U8D4NFF6Ubotas68D01go6q+2hXLysU+j9tWgb0xCK8guEW8UrOqAC5qKYh98l oAXj2ywph1q0VBL1YaUKa3woE5/+qY/u+gsDK5tvv8bqOXksYMn+tdOCm+QPCxD6kBgQ WJICZGSUg9LkFF0uvvf39sDWNh5DmoUOKFXaqTL12yyzwSsrncVxmWvLxJNIYHjfov/o ww== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 360kcykkxe-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 11 Jan 2021 22:11:58 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10BM6SaB101267; Mon, 11 Jan 2021 22:09:58 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 360keftbsv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 11 Jan 2021 22:09:57 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 10BM9uUV017394; Mon, 11 Jan 2021 22:09:56 GMT Received: from [10.39.223.157] (/10.39.223.157) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 11 Jan 2021 14:09:56 -0800 Subject: Re: [PATCH] xen/privcmd: allow fetching resource sizes To: Roger Pau Monne , linux-kernel@vger.kernel.org Cc: Juergen Gross , Stefano Stabellini , Paul Durrant , xen-devel@lists.xenproject.org References: <20210111152958.7166-1-roger.pau@citrix.com> From: boris.ostrovsky@oracle.com Organization: Oracle Corporation Message-ID: <555ba53c-1b6b-6cf7-9887-52d4179f7456@oracle.com> Date: Mon, 11 Jan 2021 17:09:54 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210111152958.7166-1-roger.pau@citrix.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9861 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 phishscore=0 spamscore=0 malwarescore=0 suspectscore=0 mlxlogscore=999 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101110123 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9861 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 impostorscore=0 bulkscore=0 adultscore=0 suspectscore=0 malwarescore=0 lowpriorityscore=0 clxscore=1011 mlxlogscore=999 mlxscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101110123 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/11/21 10:29 AM, Roger Pau Monne wrote: > > + xdata.domid = kdata.dom; > + xdata.type = kdata.type; > + xdata.id = kdata.id; > + > + if (!kdata.addr && !kdata.num) { I think we should not allow only one of them to be zero. If it's only kdata.num then we will end up with pfns array set to ZERO_SIZE_PTR (which is 0x10). We seem to be OK in that we are not derefencing pfns (either in kernel or in hypervisor) if number of frames is zero but IMO we shouldn't be tempting the fate. (And if it's only kdata.addr then we will get a vma but I am not sure it will do what we want.) -boris