Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   "Tian, Kevin" <kevin.tian@intel.com>
To:     "Zhang, Tina" <tina.zhang@intel.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        "Lu Baolu" <baolu.lu@linux.intel.com>,
        Michael Shavit <mshavit@google.com>
CC:     "iommu@lists.linux.dev" <iommu@lists.linux.dev>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 0/5] Share sva domains with all devices bound to a mm
Thread-Topic: [PATCH 0/5] Share sva domains with all devices bound to a mm
Thread-Index: AQHZyczwIC26PTEzeEyQLUQIHK3R/q/htz1g
Date:   Wed, 9 Aug 2023 09:41:20 +0000
Message-ID: <BN9PR11MB527638E7361714F8AA5FD4448C12A@BN9PR11MB5276.namprd11.prod.outlook.com>
References: <20230808074944.7825-1-tina.zhang@intel.com>
In-Reply-To: <20230808074944.7825-1-tina.zhang@intel.com>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?/wUU97SUpFh+FTg4EwjS36wfTNJPJhir4VxhNlQYvkpP9Pum/jPKYONsv3lA?=
 =?us-ascii?Q?eGucUQhSKiSQeZ0RvzK5a7E6u2ZT/tm6GA81a1PhJeaRjyMSkIGS0oWKNLuV?=
 =?us-ascii?Q?jE+H0OnagtefUNI6mzsX8pQpfXDPc2PUB9oVkT5tPLmfX1ih2cWPqZ/Y4iM2?=
 =?us-ascii?Q?Hl857AzbM3s9knb7lpKetYqw8bnSuVVOp6g9QbCwwer4wWM5/6WTHhn93kNH?=
 =?us-ascii?Q?uF7uvqDKhHGHhi9N16mOVPCeYIpWrH7Itxl0vBey3tq9DjwNv8fgd0ZY0m/A?=
 =?us-ascii?Q?fRfK8KoK/NL94pQ85Uk4ImlL3Z+GznTMnqeHAv2oWcz6ZuU3E2suwx/p6Pv5?=
 =?us-ascii?Q?UnazxvCpQ02rFlUCNHGhrIvsLcXCyWO09/rtTYLy8q/0C4f46boxTi6327lw?=
 =?us-ascii?Q?XuaJTSUwBjth/DsBY0eZZ2vTONeDxQ9qOLmZSyRTWv1k4FuZu0qaETPbuCGr?=
 =?us-ascii?Q?TB03jARamKgsGAo+I+pVnzD35ictwUE3gVeAVhLr2CDZc0okSBD+hWUaNLc0?=
 =?us-ascii?Q?v0KutKl8+WlCX577422ojwJT84gKuyDrF+uOZXZ5hJn06+3Xqzzp+SF5PgTO?=
 =?us-ascii?Q?PWD0GTFI9fU2Mbpy8Uz4DhfjrKgBYTPLcxQKLwEwC+OXnNgFb9HJfFd8mT8G?=
 =?us-ascii?Q?OqQzqvusepqy7UbrYwYSyXJID0SuCl+Z1h9diZYl1Y/JA7+ZwLsH873HqAlY?=
 =?us-ascii?Q?fI3Da+3T1CJUooGCj45qRvdt2JY6HOE0HA5bLdPQzfC6ig4lCHbYe4YTYNcJ?=
 =?us-ascii?Q?/u4kFluo//ouYQg+h7xrRX2ZzQ3U7IeSZiJ912+2zr7hDCpIIpTmS2mb2s0o?=
 =?us-ascii?Q?9QtO7nMV3MgONh/4hIuzxTNCDRjP9KfJp7WsOFvrmisjHCiaQON5opQpeIuD?=
 =?us-ascii?Q?GbWgetV4nppyekchywOJvt6Pkgv5ovZwijo0mZug5MDeFgioPS7zoft0s/8Q?=
 =?us-ascii?Q?dE4Lpk/GP2i4QWEJ1v5ZKN2AzHiJxy4ClTGZr1RnmQu8GOXR972e6Fj4oCZB?=
 =?us-ascii?Q?nb849tqXZ6I20jXFoeVl8qEbEZom9CDpfPu/L7RQUK0aHcokz5ZfzRl7md/9?=
 =?us-ascii?Q?jCQisPHnDKdM04Nog1CVn51KG/p/j8uFl2PWU6nnYf09yfjEGmkzGFXx0f0Y?=
 =?us-ascii?Q?NvW41hZQS2AhkeG8y7+MW/vDMSsYdAvQ7hlmBmPDksABcseE6T9b/+hNr/1b?=
 =?us-ascii?Q?2heiwBu0L0ENzyFaQ+bNAyKbIL9IcFP1qc/GiggNG6aU7Ve/fyfO2TJcBtuQ?=
 =?us-ascii?Q?mCsSxObkx0NGcHsVaQhDqbltSCFbA+rUpKgsQ93SZaN9W6fvu1hBDAyo0BZ+?=
 =?us-ascii?Q?sjX1XqKB22e2gVpKShuKUn1yI9sIe3UQNbn/fncJ6BkbQIQdjqBPwA/Nse4f?=
 =?us-ascii?Q?xZNnHx6zoQg2tqRIE4Uae3zVP54StDXxFOGmh52v8i5AApKAgS8abSvBErPs?=
 =?us-ascii?Q?gliUzgiXQrvueAXFuSTRSh2RdljfKwWQOPl66t9bWgXQT5quL/RY+jA1mtOU?=
 =?us-ascii?Q?wNuXWvha9Eh1Zv6TPFzxquCva4sWVwr9L1DXUSVtZaZM5vuzfawQsiV9FiDg?=
 =?us-ascii?Q?hLJ+VsCqdQsvbvNdaZJddJCla5vdKWgWdiQ6nYF8?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: BN9PR11MB5276.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 2105ff72-2238-4163-273b-08db98bcc97c
X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Aug 2023 09:41:20.4323
 (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: tVC/SS94W5emE+ylhP2K6/CQQgq06lXfoAKyp0KNXxTbA6tXYwirlI38kLqGS+4THBfBTvQHvHiw+6AgnRhMPA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR11MB6379
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,
        RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,
        URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

> From: Zhang, Tina <tina.zhang@intel.com>
> Sent: Tuesday, August 8, 2023 3:50 PM
>=20
> A sva domain's lifetime begins with binding a device to a mm and ends
> by releasing all the bound devices from that sva domain. Technically,
> there could be more than one sva domain identified by the mm PASID for
> the use of bound devices issuing DMA transactions.

Could you elaborate it with some concrete examples which motivate
this change?

>=20
> To support mm PASID 1:n with sva domains, each mm needs to keep both a
> reference list of allocated sva domains and the corresponding PASID.
> However, currently, mm struct only has one pasid field for sva usage,
> which is used to keep the info of an assigned PASID. That pasid field
> cannot provide sufficient info to build up the 1:n mapping between PASID
> and sva domains.
>=20
> This patch-set fills the gap by adding an mm_iommu field[1], whose type i=
s
> mm_iommu_data struct, to replace the old pasid field. The introduced
> mm_iommu_data struct keeps info of both a reference list of sva domains
> and an assigned PASID.
>=20
>=20
> [1]: https://lore.kernel.org/linux-iommu/ZIBxPd1%2FJCAle6yP@nvidia.com/
>=20
>=20
> The RFC version of this patch-set is here:
> https://lore.kernel.org/linux-iommu/20230707013441.365583-1-
> tina.zhang@intel.com/
>=20
> Tina Zhang (5):
>   iommu: Add mm_get_pasid() helper function
>   iommu: Call helper function to get assigned pasid value
>   mm: Add structure to keep sva information
>   iommu: Support mm PASID 1:n with sva domains
>   mm: Deprecate pasid field
>=20
>  arch/x86/kernel/traps.c                       |  2 +-
>  .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   | 12 ++---
>  drivers/iommu/intel/svm.c                     |  8 +--
>  drivers/iommu/iommu-sva.c                     | 50 ++++++++++++-------
>  include/linux/iommu.h                         | 19 +++++--
>  include/linux/mm_types.h                      |  3 +-
>  kernel/fork.c                                 |  1 -
>  mm/init-mm.c                                  |  3 --
>  8 files changed, 58 insertions(+), 40 deletions(-)
>=20
> --
> 2.17.1