Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2;
Date:   Wed, 6 Dec 2023 14:32:09 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Yi Liu <yi.l.liu@intel.com>
Cc:     joro@8bytes.org, alex.williamson@redhat.com, kevin.tian@intel.com,
        robin.murphy@arm.com, baolu.lu@linux.intel.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, joao.m.martins@oracle.com,
        xin.zeng@intel.com, yan.y.zhao@intel.com
Subject: Re: [PATCH v6 1/6] iommu: Add cache_invalidate_user op
Message-ID: <20231206183209.GZ2692119@nvidia.com>
References: <20231117130717.19875-1-yi.l.liu@intel.com>
 <20231117130717.19875-2-yi.l.liu@intel.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231117130717.19875-2-yi.l.liu@intel.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?IjFjst8kbYA9JuEeFxcLYS8g6EVpM2dhnqp9VKRdq9whttMELOOXbgRebHk2?=
 =?us-ascii?Q?dl9LLHcPxfsBtZnl43PNoQR70Gk1tQGO2IAn3PLfhE5mLXX+SdA4Lmz0/pVv?=
 =?us-ascii?Q?EnspZuiCkxnnB6yAcEJ/RzWf8M8eAWJwHwxrilUSx2lgCRjNxt6Xr4G45egB?=
 =?us-ascii?Q?k7xd6Ujr8zUtcczsvPpTNXV87M0CyFV/EGevbr4yEb+eaUnfa6gk1xxAwywQ?=
 =?us-ascii?Q?ojcAT8+N8GDx3eiXwifvYigAH+srJNwo+LwqEciaZv0Yf6uYt73LxNKOnpuQ?=
 =?us-ascii?Q?yiGeZdUX2Br86ksfsQki14/b2PO1zEROnD0Tx03Uv3lCixt79iPSMCAQsNHs?=
 =?us-ascii?Q?afr1epxeeNfiolNOmYTJrQ3XbUDEXIegTSywvDbX31lY3WQa/k1p7Fnkr3ja?=
 =?us-ascii?Q?LrOkHYT0GP/KLtFExrdqpvOtMYn9hlTVXc5slof9MG1sMJvavspMHM32YNth?=
 =?us-ascii?Q?oqZdNrgP42VBHxCbZmBuLNo5isrANCjp0oGPiUx9WLlJcC7uffC002OhXeWU?=
 =?us-ascii?Q?7aQrnsEzWYlIDztfjnKSmKAPMGBvGS9qq7F48sUqn2cYj09JTncPAZEUlR5Z?=
 =?us-ascii?Q?OfHZN+Y7OiKLDaFLOf3EjsQ/BznqvRYGyjyTBIwaJGL06JJINhypa4cFp/l+?=
 =?us-ascii?Q?t3b1MtCdp9RsrfwaFKPs92sjct/WTIz8yG23G+oSQMhAE9t8HutiFJLyC0ME?=
 =?us-ascii?Q?i/tEMNFuKSQ4Sz8Kad5/IJJ3+FcBuU8tiSFBnmS6Ha5kh+ZK+GH3udTLWbvt?=
 =?us-ascii?Q?+VilkZeFtI3m3J6rGRbEJHtZ85Fp3uKw3RK8qWpvygCcWxT18YbKsi0nz6zZ?=
 =?us-ascii?Q?M49JkTUZJsID30QjV6KYQbbzf/6sTWiZesPSuy4LmKxjGz1Jqw7hCqIC32dH?=
 =?us-ascii?Q?KCI+AfDNrCGXmAF/0FZ2JjGEhFenfjuwZO79NTrTGAiI0inPW7KUPsg82BWz?=
 =?us-ascii?Q?gx17RMHK+gd72HIm9DxDugRowH7yVQCJ7VcjROx8m1bc0eVwA/4Nujy1xzbi?=
 =?us-ascii?Q?1dGnmEtpQC7VPM5inoIWYr1sygWPzhI5IE1iD9PBJ3Ad2jQLpT1bPpaX5rJM?=
 =?us-ascii?Q?4jo9D02iuTIFfOixeBPdXuKDSjTStWKFdCL33Oto5FPwG/D2g/qG56saD/lM?=
 =?us-ascii?Q?LGKj3zoRUuINOAqj0etMPIzCF//qqwX1SefWCKBYZRt5ml3IA1Nv4n4XsUa3?=
 =?us-ascii?Q?RDfK8OJMHGbpCOaLbu/SimMbPMNThGLAXri4X29aBCz8Sthvdql1e+bKUt1P?=
 =?us-ascii?Q?8CaNIDdLkkBGhycSeuO0iTNJifcubzStAPiLjsaYR5fpS5ZNrJGMYn3/I8LJ?=
 =?us-ascii?Q?Pqp8wR+GpIekOfpdlCH3T+F6iJnfMqjKafejtgh0xLqs29JhGCVUAogt7Twg?=
 =?us-ascii?Q?k/1CyrAwW5sQud0aBDoMQPGgx2CVCOoTGkN0dljqWl6qVFyhtq3Zg06Rk4SS?=
 =?us-ascii?Q?Ys8gJjlspCnWKVR3Hs+/7bbYapKaqKoK+RY/RLQJ29gZmKnOCfaC1JwHei3A?=
 =?us-ascii?Q?rzdSDstqt4HrlH6HttLpW7ShCf9agvGgEn4msYJ/Q0209UkQ5hBZyHsJUl2p?=
 =?us-ascii?Q?8S7Hx5JCl2whaOiTtOMoEEC/bi8eObYrNxHW5WpL?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 960c16b9-eb15-44bb-42aa-08dbf689a8d0
X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Dec 2023 18:32:10.7675
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: JXuEgBsvmQCTAQ4SAc5Omd8oO1lRJERSU09BfYR0JiuLIrRXO2lEhNyuJPGNaai3
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB8026
X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE
	autolearn=unavailable autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on agentk.vger.email
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (agentk.vger.email [0.0.0.0]); Wed, 06 Dec 2023 10:32:23 -0800 (PST)

On Fri, Nov 17, 2023 at 05:07:12AM -0800, Yi Liu wrote:
> +/**
> + * struct iommu_user_data_array - iommu driver specific user space data array
> + * @type: The data type of all the entries in the user buffer array
> + * @uptr: Pointer to the user buffer array for copy_from_user()
> + * @entry_len: The fixed-width length of a entry in the array, in bytes
> + * @entry_num: The number of total entries in the array
> + *
> + * A array having a @entry_num number of @entry_len sized entries, each entry is
> + * user space data, an uAPI defined in include/uapi/linux/iommufd.h where @type
> + * is also defined as enum iommu_xyz_data_type.
> + */
> +struct iommu_user_data_array {
> +	unsigned int type;
> +	void __user *uptr;
> +	size_t entry_len;
> +	int entry_num;

These are u32 in the uapi, they should probably be u32 here
too. Otherwise we have to worry about truncation.

> @@ -465,6 +492,9 @@ struct iommu_domain_ops {
>  			      size_t size);
>  	void (*iotlb_sync)(struct iommu_domain *domain,
>  			   struct iommu_iotlb_gather *iotlb_gather);
> +	int (*cache_invalidate_user)(struct iommu_domain *domain,
> +				     struct iommu_user_data_array *array,
> +				     u32 *error_code);

Regarding the other conversation I worry a u32 error_code is too small.

Unfortunately there is no obvious place to put something better so if
we reach it we will have to add more error_code space via normal
extension.

Maybe expand this to u64? That is 64 bits of error register data and
the consumer index. It should do for SMMUv3 at least?

Jason