Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.36 as permitted sender) client-ip=23.128.96.36;
Message-ID: <05dec0b1-61ac-c3af-e238-322c1eec57ec@intel.com>
Date:   Sat, 7 Oct 2023 17:38:17 +0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Firefox/102.0 Thunderbird/102.13.0
Subject: Re: [PATCH v4 01/17] iommu: Add hwpt_type with user_data for
 domain_alloc_user op
Content-Language: en-US
To:     "Tian, Kevin" <kevin.tian@intel.com>,
        Jason Gunthorpe <jgg@nvidia.com>
CC:     Robin Murphy <robin.murphy@arm.com>,
        Baolu Lu <baolu.lu@linux.intel.com>,
        "joro@8bytes.org" <joro@8bytes.org>,
        "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
        "cohuck@redhat.com" <cohuck@redhat.com>,
        "eric.auger@redhat.com" <eric.auger@redhat.com>,
        "nicolinc@nvidia.com" <nicolinc@nvidia.com>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "mjrosato@linux.ibm.com" <mjrosato@linux.ibm.com>,
        "chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>,
        "yi.y.sun@linux.intel.com" <yi.y.sun@linux.intel.com>,
        "peterx@redhat.com" <peterx@redhat.com>,
        "jasowang@redhat.com" <jasowang@redhat.com>,
        "shameerali.kolothum.thodi@huawei.com" 
        <shameerali.kolothum.thodi@huawei.com>,
        "lulu@redhat.com" <lulu@redhat.com>,
        "suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
        "iommu@lists.linux.dev" <iommu@lists.linux.dev>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>,
        "Duan, Zhenzhong" <zhenzhong.duan@intel.com>,
        "Martins, Joao" <joao.m.martins@oracle.com>
References: <20230921075138.124099-1-yi.l.liu@intel.com>
 <20230921075138.124099-2-yi.l.liu@intel.com>
 <0d37a1b1-e7ef-fa73-d17c-629cd254ae75@linux.intel.com>
 <20230921164447.GQ13733@nvidia.com>
 <dcde6757-8d14-6460-c75e-c30d69219e4b@arm.com>
 <BN9PR11MB52765B3F127EE04E4A79C7778CC3A@BN9PR11MB5276.namprd11.prod.outlook.com>
 <20230926162920.GQ13733@nvidia.com>
 <BN9PR11MB527645B87FB0150E9C7AF4D88CC2A@BN9PR11MB5276.namprd11.prod.outlook.com>
From:   Yi Liu <yi.l.liu@intel.com>
In-Reply-To: <BN9PR11MB527645B87FB0150E9C7AF4D88CC2A@BN9PR11MB5276.namprd11.prod.outlook.com>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?eFBHNG1DZWZjMHM5cGxtTnRod0dzaFJwTlk2bWdnVldsVnFaQ3JFekhtM05v?=
 =?utf-8?B?U0NBcEplOUtGZGpmdW5SZG54M2trZU8xdmsvVUpkbUdqVFJqeXl6ay9heXRQ?=
 =?utf-8?B?T01tVVN3UHhOK09tUTBMdjhKZkM3eGpDZWx4Qi9wSER5UXR1dEozYmJiWkxY?=
 =?utf-8?B?VzQyYTlISzNPZXZoVnh2ampGTkM4V2JYbWZLSm5BbDRzUEJGd0w5VzZLTmlI?=
 =?utf-8?B?akZaNlo4TDV5WXFaS25nWkVSVWxYKzdlSk9FUkJyNy9FWjJISXpLMFVnS0hW?=
 =?utf-8?B?TXZJNW02M01QQTFKQXJCV2N5dXlSSWpBbm94ZXhKZHJaU3l5cU14alNUTkRs?=
 =?utf-8?B?aVBTaUo1aVhENDM1RGpZREs2SGNrMWFlK2VEZkRLcVNIdnVrZmd5RG5yYy9j?=
 =?utf-8?B?c2puY1V2NGFVTDNIanZpdFJhZXMrV3U3OUdBQlhtaHpNaTRWdkJrNWREbEJR?=
 =?utf-8?B?bW1tUFpxcDJnSW8zWGVKQ20wM0JTdVdZLzVZQ0RqeXdscDlIRlRaVm5JaHpl?=
 =?utf-8?B?bUFWNU5OcUlvUDFCeWFxeGczV1NkY0hJNVVTNHpiN2pnU3NZSTRieFVwM0FH?=
 =?utf-8?B?RXI3TUpkZExSbm5Xc3dkU3pkazgzMGlVUmFQbjJ1RU1lUVZ1dkhjOUd4UjBT?=
 =?utf-8?B?T2FLV2xsR1R3Z2J6a0tjcHN6UW44Yjg4dVlaa1JpTGxkRGtYM2FDVFBncnpH?=
 =?utf-8?B?RUhxUk1CNXFqOHFvalh1cVNmQ1RrVmxWMjdlSk9PNnZnNWZBS1huc0pBQTZZ?=
 =?utf-8?B?djUvWFczck1iK3dQaGF1UEtZOEgramNPQjY4RHBZempnZG55R0RLdko2MlEz?=
 =?utf-8?B?eGVoSm85ZVBQcnQvTS85d0VsKytDZGhFaXBLanNKWDNLSG14eEpCZUNmelZG?=
 =?utf-8?B?cExuN2VWVU0rK0RNLzJOL3RsSWdpQWlwQmR3Y2JrVmVzYzFsSG9lZnM2UTZH?=
 =?utf-8?B?S0F0NjNoZzAyVW9ORlZDY0U4UXcyRGR0WDdvT2xWajVvaGwrRnE1ZU9FT05n?=
 =?utf-8?B?emg0RWNMWmJoZUtEVzVkSnFyYVlWbElYUjhDdloxVEtpODB1eWxZZy8va21O?=
 =?utf-8?B?RjN6Q29zRnFYZTRZT2RvVm9kR2ZvM0ExbE5CWCtPL3cxTjgwc2RzeHdGZ0Nv?=
 =?utf-8?B?WnpNSVluL20yYkMrT0ZpeCtPaktqZkhLL1ZLajJtVjZ5eXBVM2hFVTlwTUpr?=
 =?utf-8?B?Qjk1VnZ1RzFYYUw5cTI0alFtclZOSi8wUFNEQWlLTjI2OG1zb2k4L0NqRGlD?=
 =?utf-8?B?SzUxblFkQy9yc0NHaXYyTXBpajZkYm13T0wzNk5HWk9HYUtqVEVCT1hEWHBY?=
 =?utf-8?B?aTR6YlozMEJpYUtQRjlxRUhaVjR2c0VGVVRqcGd6YVU4c3FyM2dHeU13YmRn?=
 =?utf-8?B?NHVTWnpGeFZ6U2grb1E1R2w4RDNLUXF4cjZZeGZXdmxkMDYwRlU0L2VMd2Fx?=
 =?utf-8?B?emt4N3Rjd2tSdFNCa3JMUjF6QlhuMERCcmxlamhWUlN4V2lMd1JhUno4QnQ5?=
 =?utf-8?B?RlYvdVZKWFc0ZUJPNGFlNkRLRmRZejIxNXZXbk9xVjI1M1ZNRWtXVk16UXpC?=
 =?utf-8?B?T3ZGZ2xoaUs5dXIvOFZuajdDZmFPbG00S0VsUUtxMUVtSHpNNzVGSEhRZVhW?=
 =?utf-8?B?MmFpQTM1aGU0MEgxd2ZPejMzQTFkeTJocklvYjd6VmU1OUxXTzFCamdqbCtY?=
 =?utf-8?B?MmpXYlRFcVFkZk1hUG1iUFN4eDAvMURxNmVCZnEvY3FNQkVjOWxkYXFRWGky?=
 =?utf-8?B?azltK1RSNURhUUN5ekY1MVU1K2JkR2RkczhISlZXS3A4WUhNbHFGUHo5VGZs?=
 =?utf-8?B?b2F5UjNWUnJqSzBYUjE2dFJ2QVRMRG5WQk5jZjJvd3FSWlFiMHlBZG1XNEk2?=
 =?utf-8?B?MTVOakZnQ2NVNktWZUdKMmNzSDhiVWJnYXVqZkRQMlpIelcvWmlpS0N1RmpG?=
 =?utf-8?B?Z2FUN014MlpiL2tVU09TT0UxKzMvSjd2WHdQY3ZOblpSTmRrcFNrd1RIeEZF?=
 =?utf-8?B?T1kyeVNwNGgwYWliNWx6MThGN21KVHhsMzBlQzhDYytraHdobi8zalNxWkFt?=
 =?utf-8?B?QnJicjJTU29aaWNBM0lESmpxSmpyek5VQ3Vmc2QwVHJMalZmbnhkcWhSSk04?=
 =?utf-8?Q?qQuw4XKjGuoGOlkuiS3gy0SfP?=
X-MS-Exchange-CrossTenant-Network-Message-Id: a0f5d95b-d5a6-4663-6da7-08dbc718d0cc
X-MS-Exchange-CrossTenant-AuthSource: DS0PR11MB7529.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Oct 2023 09:36:00.5330
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: oWhsyxDVmbH+H9GiPNeYD/7y0Goqn6BZfVLnvIm0yLfNRSPJgVsF8ev4A0Cs4KTd4pjlRUoei5HXIv2H2s+efQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR11MB6536
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=2.1 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,NICE_REPLY_A,RCVD_IN_SBL_CSS,SPF_HELO_NONE,SPF_PASS
	autolearn=no autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on pete.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 (pete.vger.email [0.0.0.0]); Sat, 07 Oct 2023 02:40:21 -0700 (PDT)
X-Spam-Level: **

On 2023/9/27 09:08, Tian, Kevin wrote:
>> From: Jason Gunthorpe <jgg@nvidia.com>
>> Sent: Wednesday, September 27, 2023 12:29 AM
>>
>> On Tue, Sep 26, 2023 at 06:37:55AM +0000, Tian, Kevin wrote:
>>>> From: Robin Murphy <robin.murphy@arm.com>
>>>> Sent: Friday, September 22, 2023 5:48 PM
>>>>
>>>> I could go on enjoying myself, but basically yeah, "default" can't be a
>>>> type in itself (at best it would be a meta-type which could be
>>>> requested, such that it resolves to some real type to actually
>>>> allocate), so a good name should reflect what the type functionally
>>>> *means* to the user. IIUC the important distinction is that it's an
>>>> abstract kernel-owned pagetable for the user to indirectly control via
>>>> the API, rather than one it owns and writes directly (and thus has to be
>>>> in a specific agreed format).
>>>>
>>>
>>> IOMMU_HWPT_TYPE_KERNEL then?
>>>
>>> IOMMU_HWPT_TYPE_GENERIC also doesn't sound a straight word.
>>
>> At the end of the day this enum is the type tag for:
>>
>>   struct iommu_hwpt_alloc {
>>   	__u32 size;
>>   	__u32 pt_id;
>>   	__u32 out_hwpt_id;
>>   	__u32 __reserved;
>> +	__u32 hwpt_type;
>> +	__u32 data_len;
>> +	__aligned_u64 data_uptr;
>>   };
>>
>> That pointer.
>>
>> IOMMU_HWPT_ALLOC_DATA_NONE = 0
>> IOMMU_HWPT_ALLOC_DATA_INTEL_VTD
>> IOMMU_HWPT_ALLOC_DATA_ARM_SMMUV3
>>
>> etc?
>>
>> DATA_NONE requires data_len == 0
>>
> 
> Looks good. Probably hwpt_type can be also renamed to data_type
> to better match this interpretation.

ack.

-- 
Regards,
Yi Liu