Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
From:   "Limonciello, Mario" <Mario.Limonciello@amd.com>
To:     Mika Westerberg <mika.westerberg@linux.intel.com>,
        Robin Murphy <robin.murphy@arm.com>
CC:     "andreas.noever@gmail.com" <andreas.noever@gmail.com>,
        "michael.jamet@intel.com" <michael.jamet@intel.com>,
        "YehezkelShB@gmail.com" <YehezkelShB@gmail.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "hch@lst.de" <hch@lst.de>
Subject: RE: [PATCH] thunderbolt: Stop using iommu_present()
Thread-Topic: [PATCH] thunderbolt: Stop using iommu_present()
Thread-Index: AQHYOSidJZwMFUwbGEibeELZIyT74azB9QiAgAAiooCAACnRgIAAAPcA
Date:   Wed, 16 Mar 2022 17:24:38 +0000
Message-ID: <BL1PR12MB515762E68F3A48A97EB2DC89E2119@BL1PR12MB5157.namprd12.prod.outlook.com>
References: <b4356b228db9cb88d12db6559e28714ce26e022e.1647429348.git.robin.murphy@arm.com>
 <YjHb1xCx4UAmUjrR@lahna> <16852eb2-98bb-6337-741f-8c2f06418b08@arm.com>
 <YjIb+XOGZbWKpQDa@lahna>
In-Reply-To: <YjIb+XOGZbWKpQDa@lahna>
Accept-Language: en-US
Content-Language: en-US
msip_labels: MSIP_Label_d4243a53-6221-4f75-8154-e4b33a5707a1_Enabled=true;
 MSIP_Label_d4243a53-6221-4f75-8154-e4b33a5707a1_SetDate=2022-03-16T17:24:29Z;
 MSIP_Label_d4243a53-6221-4f75-8154-e4b33a5707a1_Method=Privileged;
 MSIP_Label_d4243a53-6221-4f75-8154-e4b33a5707a1_Name=Public-AIP 2.0;
 MSIP_Label_d4243a53-6221-4f75-8154-e4b33a5707a1_SiteId=3dd8961f-e488-4e60-8e11-a82d994e183d;
 MSIP_Label_d4243a53-6221-4f75-8154-e4b33a5707a1_ActionId=a9459524-06b3-42d9-b785-f0bd583d535a;
 MSIP_Label_d4243a53-6221-4f75-8154-e4b33a5707a1_ContentBits=1
msip_label_d4243a53-6221-4f75-8154-e4b33a5707a1_enabled: true
msip_label_d4243a53-6221-4f75-8154-e4b33a5707a1_setdate: 2022-03-16T17:24:36Z
msip_label_d4243a53-6221-4f75-8154-e4b33a5707a1_method: Privileged
msip_label_d4243a53-6221-4f75-8154-e4b33a5707a1_name: Public-AIP 2.0
msip_label_d4243a53-6221-4f75-8154-e4b33a5707a1_siteid: 3dd8961f-e488-4e60-8e11-a82d994e183d
msip_label_d4243a53-6221-4f75-8154-e4b33a5707a1_actionid: c565fffc-7a9d-4612-bf2e-9df837f5e257
msip_label_d4243a53-6221-4f75-8154-e4b33a5707a1_contentbits: 0
authentication-results: dkim=none (message not signed)
 header.d=none;dmarc=none action=none header.from=amd.com;
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: c3df5221-e65d-4fff-9007-08da0771d937
x-ms-traffictypediagnostic: BN8PR12MB3425:EE_
x-microsoft-antispam-prvs: <BN8PR12MB3425D2C31D5F2FFCC62DFE91E2119@BN8PR12MB3425.namprd12.prod.outlook.com>
x-ms-exchange-senderadcheck: 1
x-ms-exchange-antispam-relay: 0
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info: 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
x-forefront-antispam-report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BL1PR12MB5157.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230001)(4636009)(366004)(316002)(71200400001)(2906002)(38070700005)(86362001)(5660300002)(9686003)(45080400002)(966005)(33656002)(508600001)(66946007)(4326008)(54906003)(55016003)(66556008)(66476007)(66446008)(64756008)(8676002)(110136005)(83380400001)(52536014)(8936002)(122000001)(186003)(38100700002)(6506007)(7696005)(76116006);DIR:OUT;SFP:1101;
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?MECIOMImi6L7iss9zjgMiE2pxxze+PMpBJzqVnXTGa8ieU5fr13DHizXFxhn?=
 =?us-ascii?Q?yC0Q98Wlh/cv1Ryw4lAkX1rhCzSNVsSRUOP4Qe52BGvJvV42HotKgnfcYK0k?=
 =?us-ascii?Q?kbg3FwP20KBuJDmdCFlsHFyJG0L20MUuhRTujnm4/0jjvyeyCx0kfWPmY03O?=
 =?us-ascii?Q?fhDybeMKYBeuxr24t49XBgy0ohqL/XZuzEjr9PM5TxrtI4/Lln/OdIoHNWAy?=
 =?us-ascii?Q?uGpqz0n5jj9nrJ0VkhsQaJnGJ6IJ0IFUbjA8+z+ostzi10egloqH9j9DcQY9?=
 =?us-ascii?Q?0/0Lr7AFl+xhsP3PJmLg3eMqsT5vC3+X4M/eS4NZc/E8SCOIffGW8+6MpRk9?=
 =?us-ascii?Q?5TUrRm0Nvbz1dbyIM84dXcz+YXJXKFfJc9CbXz/By0YIBvI4X1Lj4P/IPjfc?=
 =?us-ascii?Q?ct/IQYpOQTsuEWEDYeRv49ruDwjYkLdf5kYUUWV25QNUHQhPzRnazZUJXBqn?=
 =?us-ascii?Q?B2/Cdc1zb9eBxrxwFAmYWFJen3VuMpvwh7K42YKhZ+90318DqwwWL0J2kqQG?=
 =?us-ascii?Q?sdVLrMenYBscEJ0ywzuPZQM9aPiCLgvCkp8eKyxKpuForHiD3jyWxbm5muIy?=
 =?us-ascii?Q?D+n1BqdMyPPCgrt2tpghBkVixAHzxHVOGpxWSqJXQCOjTJyf21tvYmRekPTZ?=
 =?us-ascii?Q?0p2DBKxipXI/8+azPVn89TOJfoYoO6lTV3SPbtVK5N8l8EoJQgSr7Cue8VUP?=
 =?us-ascii?Q?Xl6cAO8/Q4MBkYKIO23n+5rH3Vo4aZ5rybNo2/xG6Hp9EG1+2m8Va85W+VsN?=
 =?us-ascii?Q?jiXxf3NF85aCL0Ckk8shKWG5wyNqe/ZiVBoKPgVymr2WIHxMKlTPzetDpVMw?=
 =?us-ascii?Q?eIHrrcgl/GFE11SXcR4DUhrQ5PmLwp/Ly5uG5Ju5U+LoH0i94msDbPNAI8aU?=
 =?us-ascii?Q?xv71f4uO5xRcdXcha81EVoy/xQiB55rJgyyjqsKEdZ4qCHevnZ0YikXF9rmF?=
 =?us-ascii?Q?JtpNGa9WA3QVuSrYIxKuWKiCr5NNVtAvlU7UoVGF7RW8SOGg9LMJRwCXW01D?=
 =?us-ascii?Q?Wi3RMRd6j+3cuGTIXj1KqkjEPErdX0ZOBiDvp5+eGqLeM9wFJr2A0TSj2skT?=
 =?us-ascii?Q?CQcO3k71NfSklqDh8jPoh7i8IR4SHmwY5DaH1KVTO+4xY0AwXXIh1duJfDHp?=
 =?us-ascii?Q?jPSY0Fu6sLPg7u6S/2+WAjtkikPVGaMTbmbHoG+15PEK8CbPY/GFThycC/SF?=
 =?us-ascii?Q?/iCRDYX2EmVDs76szREGGRSNsdWgrMmAJp/pGOutiObyWZ4YHjZhAr7ewoBT?=
 =?us-ascii?Q?z2XCaXrR5FdXiR2V5nYnLS2in5tLEwwxUOsOlcCjDPJ/HvIXbcpzsWH+kp41?=
 =?us-ascii?Q?QuIZvAzjEIwD6arRXna1fl6B/obwXTnJdSRe7FBWZj1sYyNSrR6h74j0GLqD?=
 =?us-ascii?Q?I7eP9Zm0Ve2m9UzVCcSQTL5mWq1TrZugPZASSKj2BhuorIhhpD88YPeW50/D?=
 =?us-ascii?Q?sB80PxWERYqpFN+CBEB0wQhFJzpZiwdbnsYGBqhxCqY8hoxa2z0am6B0NoPC?=
 =?us-ascii?Q?KnA7hn883IEoKyePj9MHVEeiayJoacxz7AB1?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: BL1PR12MB5157.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: c3df5221-e65d-4fff-9007-08da0771d937
X-MS-Exchange-CrossTenant-originalarrivaltime: 16 Mar 2022 17:24:38.1333
 (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: D4v1LJCNN7Sq3heEL1pgsczHkNdfKF+3HueBsAznT+kvMvTKIVdSVvqF7dpPfutxyfdvHGwg7jCSTXPhMLWKaA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN8PR12MB3425
X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,RDNS_NONE,SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE
	autolearn=no 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

[Public]

> On Wed, Mar 16, 2022 at 02:49:09PM +0000, Robin Murphy wrote:
> > > What we want is to make sure the Tunneled PCIe ports get the full
> IOMMU
> > > protection. In case of the discrete above it is also fine if all the
> > > devices behind the PCIe root port get the full IOMMU protection. Note=
 in
> > > the integrated all the devices are "siblings".
> >
> > Ah, OK, I wasn't aware that the NHI isn't even the right thing in the f=
irst
> > place :(
> >
> > Is there an easy way to get from the struct tb to a PCI device represen=
ting
> > the end of its relevant tunnel, or do we have a circular dependency
> problem
> > where the latter won't appear until we've authorised it (and thus the
> IOMMU
> > layer won't know about it yet either)?
>=20
> The PCIe root ports (and the PCIe downstream ports) are there already
> even without "authorization".
>=20
> There is a way to figure out the "tunneled" PCIe ports by looking at
> certain properties and we do that already actually. The BIOS has the
> following under these ports:
>=20
> https://nam11.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Fdocs
> .microsoft.com%2Fen-us%2Fwindows-hardware%2Fdrivers%2Fpci%2Fdsd-
> for-pcie-root-ports%23identifying-externally-exposed-pcie-root-
> ports&amp;data=3D04%7C01%7Cmario.limonciello%40amd.com%7C0465d319a
> 6684335d9c208da07710e7c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7
> C0%7C637830479402895833%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4w
> LjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&am
> p;sdata=3Dz6hpYGpj%2B%2BVvz9d6MXiO4N66PUm4zwhOdI%2Br6l3PjhQ%3D
> &amp;reserved=3D0
>=20
> and the ports will have dev->external_facing set to 1. Perhaps looking
> at that field helps here?

External facing isn't a guarantee from the firmware though.  It's something=
 we
all expect in practice, but I think it's better to look at the ones that ar=
e from
the _DSD usb4-host-interface to be safer.

Mika, you might not have seen it yet, but I sent a follow up diff in this t=
hread
to Robin's patch.  If that looks good Robin can submit a v2 (or I'm happy t=
o do
so as well as I confirmed it helps my original intent too).