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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BDE64EB64DD for ; Thu, 10 Aug 2023 02:06:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230230AbjHJCGG (ORCPT ); Wed, 9 Aug 2023 22:06:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229611AbjHJCGF (ORCPT ); Wed, 9 Aug 2023 22:06:05 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B34CF3; Wed, 9 Aug 2023 19:06:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691633163; x=1723169163; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=LwSdYv2U/EME+IZ0lQwbvUUwI+VkBqY/yWwfc4nDKLM=; b=iWSHh1khG/a7KUCXvo5s4a3h3JqQiroSKhR8M/5Y9cTEvX6kqfb8kc7C leCy7c6s/MKQcp3GZ00J+9BNw08U488JeGAvG9zlC7SYSBcxj882X8/sd 7GMI72hCdr0HkFGi2SlscDIFX7ONp01DoKCYxKRbUz5mpJd2afL5pDsOC IRRF48iSiIiB1jxfSlyy0AwPHvLIAziG2u3ZSWO2P4I3Zu1qjjnl7X/Bn uBd2e13XemiWTD+ZpQyId7wkdNMJlS1OqJ/az1l5hcnn+9CHt+VthuvS4 14Q1BC8clB86DNU8YN8K1qx8rISfff5H2c6swJWMFXhocRWwJp9nncbsc g==; X-IronPort-AV: E=McAfee;i="6600,9927,10797"; a="374056985" X-IronPort-AV: E=Sophos;i="6.01,160,1684825200"; d="scan'208";a="374056985" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Aug 2023 19:06:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10797"; a="801982441" X-IronPort-AV: E=Sophos;i="6.01,160,1684825200"; d="scan'208";a="801982441" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.254.214.239]) ([10.254.214.239]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Aug 2023 19:05:57 -0700 Message-ID: Date: Thu, 10 Aug 2023 10:05:55 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Cc: baolu.lu@linux.intel.com, Yi Liu , joro@8bytes.org, alex.williamson@redhat.com, kevin.tian@intel.com, robin.murphy@arm.com, cohuck@redhat.com, eric.auger@redhat.com, nicolinc@nvidia.com, kvm@vger.kernel.org, mjrosato@linux.ibm.com, chao.p.peng@linux.intel.com, yi.y.sun@linux.intel.com, peterx@redhat.com, jasowang@redhat.com, shameerali.kolothum.thodi@huawei.com, lulu@redhat.com, suravee.suthikulpanit@amd.com, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, zhenzhong.duan@intel.com Subject: Re: [PATCH v6 3/4] iommufd: Add IOMMU_GET_HW_INFO Content-Language: en-US To: Jason Gunthorpe References: <20230808153510.4170-1-yi.l.liu@intel.com> <20230808153510.4170-4-yi.l.liu@intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On 2023/8/10 0:16, Jason Gunthorpe wrote: > On Wed, Aug 09, 2023 at 06:16:19PM +0800, Baolu Lu wrote: >> On 2023/8/8 23:35, Yi Liu wrote: >>> +static int iommufd_fill_hw_info(struct device *dev, void __user *user_ptr, >>> + unsigned int *length, u32 *type) >>> +{ >>> + const struct iommu_ops *ops; >>> + unsigned int data_len; >>> + void *data; >>> + int rc = 0; >>> + >>> + ops = dev_iommu_ops(dev); >>> + if (!ops->hw_info) { >>> + *length = 0; >>> + *type = IOMMU_HW_INFO_TYPE_NONE; >>> + return 0; >>> + } >>> + >>> + data = ops->hw_info(dev, &data_len, type); >>> + if (IS_ERR(data)) >>> + return PTR_ERR(data); >>> + >>> + /* >>> + * drivers that have hw_info callback should have a unique >>> + * iommu_hw_info_type. >>> + */ >>> + if (WARN_ON_ONCE(*type == IOMMU_HW_INFO_TYPE_NONE)) { >>> + rc = -ENODEV; >>> + goto err_free; >>> + } >>> + >>> + *length = min(*length, data_len); >>> + if (copy_to_user(user_ptr, data, *length)) { >> copy_to_user() returns the number of bytes that were successfully >> copied, right? > It returns length on failure and 0 on success Then it's fine. Thanks for the explanation. Best regards, baolu