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Shutemov" , Andi Kleen , Tony Luck , Marc Orr , Sathyanarayanan Kuppuswamy , Alper Gun , "Dr. David Alan Gilbert" Subject: RE: [PATCH Part2 v6 02/49] iommu/amd: Introduce function to check SEV-SNP support Thread-Topic: [PATCH Part2 v6 02/49] iommu/amd: Introduce function to check SEV-SNP support Thread-Index: AQHYhYN//Jq12JdNiEyvNHxMVTEAQ61aILsggAADK4CAZRTwgIAAAKeAgAK0CKA= Date: Fri, 26 Aug 2022 18:54:16 +0000 Message-ID: References: <12df64394b1788156c8a3c2ee8dfd62b51ab3a81.1655761627.git.ashish.kalra@amd.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: msip_labels: MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_Enabled=true; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_SetDate=2022-08-26T18:47:21Z; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_Method=Standard; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_Name=General; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_SiteId=3dd8961f-e488-4e60-8e11-a82d994e183d; MSIP_Label_4342314e-0df4-4b58-84bf-38bed6170a0f_ActionId=01131e74-f26b-4805-aa08-cfbb5956557d; 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charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: SN6PR12MB2767.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: fc5bf462-8a5f-4767-6e92-08da87946010 X-MS-Exchange-CrossTenant-originalarrivaltime: 26 Aug 2022 18:54:16.2633 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: UroD/I0WsGYZZCb/6XOqTlndwb1wq8INQAVry840mSLb/8eVTaNiimKyz1DOsagqBzdIqaEPtEGYiq5EUX0U9g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5334 [AMD Official Use Only - General] Hello Jarkko, >>=20 >> It really should be, in order to have any practical use: >>=20 >> if (no_iommu) { >> pr_err("SEV-SNP: IOMMU is disabled.\n"); >> return false; >> } >>=20 >> if (iommu_default_passthrough()) { >> pr_err("SEV-SNP: IOMMU is configured in passthrough mode.\n"); >> return false; >> } >>=20 >> The comment is *completely* redundant, it absolutely does not serve=20 >> any sane purpose. It just tells what the code already clearly stating. >>=20 >> The combo error message on the other hand leaves you to the question=20 >> "which one was it", and for that reason combining the checks leaves=20 >> you to a louse debugging experience. >Also, are those really *errors*? That implies that there is something wron= g. >Since you can have a legit configuration, IMHO they should be either warn = or info. What do you think? >They are definitely not errors Yes, they can be warn or info, but as I mentioned above this patch is now p= art of IOMMU + SNP series, so these comments are now relevant for that. Thanks, Ashish