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charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: IA1PR11MB6097.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 51b69501-b92e-420a-4a81-08daef5f8c8e X-MS-Exchange-CrossTenant-originalarrivaltime: 05 Jan 2023 20:58:08.5226 (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: +vMODae7SdzAKOtv9n7FkyC885gY62LT0AIMoG4ZrI87gsoyoBT+Iv4AZYXBb6Yc1c33+snftPY1iGU44Vdx6Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR11MB6947 X-OriginatorOrg: intel.com X-Rspam-User: X-Rspamd-Queue-Id: 560DF20009 X-Rspamd-Server: rspam01 X-Stat-Signature: nxuhtcsw4hu4oqyfrdcrxyt1d3qz6kba X-HE-Tag: 1672952293-450416 X-HE-Meta: U2FsdGVkX18Bft/99KnIEBz/DtGSyyJvjJt6AMUUVf823sOOX1WbnMrl72w3dxUEqmFrjTqmpIy8Re34OoAmLbkOYeJqWZ6yIPWKabKSahYApjBeWWdjTlMftxU+Uk5kZiPWLBYRv5gn4tuLiXl44OzjXpHltZ+yMNjwf+12vvtv7scOsCHotU7S7y5+pkRxdC49wyxUkjhcqm9oPGLY5gahZNLZNZtburqB8edfsyO3wLAEy3PpW5EL3ituN+LVbo2lz90F4fua/uOkGvqW4gRfXXuEcKmDUlp7u084GNK00PJZU7B3glbDYru0UGGmqAV0hWSapiK0mzjXf+yPTyyqN5+cpc0L05dezRcPlbcpOUH20UQLM4wF4vDKvauZCKtBbKwVbkGoz70hzLsO66lomBzqj0W9c8c+HcS2HOdhnGJRyEb78YbtJvv2LzgQWXI8RpF9eXsWzjwXSpT6h4bVsEcStCgkuvONGqVVPsr778vlRtLspjVo9sBKu8QbukhMrnc7lkg2/cjXADPaN42ZT12GWQ7mSNj9Ov9NHzjwM0LTvTGeR3+B3j9IlstmM37K6VSq1MPnAYxjPKbNnairABUQmxgkC1t46GJnStMbLjNAV4rde4Yax2berDcgQTjj7N4sC/+qDq/C0iLUlbjXVILrS/N8Rvmh8pNej8yrPkEeZVqVnrx81qgoCO5CE7uRwCfJSiB7yR2Yp+iwCRdJwu/vDY6/AVELI0U7jBsT64D23ws195hXSOgPOF1mNcxicjWwdUccJg8FvXeWrvmHT3pAianvCnzPde5sPEeD8bvdAQ41y1H4Upcrxw0eiJBrKytXfzRJYJqrSdZrdUXnHLoc3qSdoCzLimFxmuHgxD1EOd40Mghiga7uqsS3ceGqwA114QaGt3r4sjb1V8gWPtaSiH8etLjewgGK1Yb73bPTPt3PXi4avv/P4vHvL8Qkb0iII0qn+KiuiIV IDq83a1+ t0GsSObcA01eSHmRGmXPtASBM9rR1GDODLbtRGpB1vTfImJPT6iOmt/GLUXSe9r7yGSVbH3cGfOoP1B0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi, Alistair, > >> Alistair Popple writes: > >> Lorenzo Stoakes writes: > >> > My concern is exposing something highly delicate _which accesses > >> > remote mas a public API with implicit assumptions whose one and > >> > only (core kernel) user treats with enormous caution. Even if this > >> > iommu code were to use it correctly, we'd end up with an interface > >> > which could be > >> subject to real risks which other drivers may misuse. > >> > >> Ok, although I think making this an iommu specific wrapper taking a > >> PASID rather than mm_struct would make the API more specific and less > >> likely to be misused as the mm_count/users lifetime issues could be > >> dealt with inside the core IOMMU code. > > > > The iommu specific wrapper still needs to call access_remote_vm() > > which is in generic mm. We cannot avoid to export access_remote_vm(), r= ight? >=20 > The wrapper still needs to call access_remote_vm(), but that doesn't impl= y > access_remote_vm() needs to be exported. I think the logical place to put= the > wrapper would be in iommu-sva.c which isn't built as a module, so you wou= ld > only have to EXPORT_SYMBOL_GPL the wrapper and not access_remote_vm(). This looks better than exporting access_remote_vm(). I will remove this pat= ch and write the IOMMU wrapper to call access_remote_vm() in v2. Thanks. -Fenghua