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;
Date:   Tue, 27 Sep 2022 13:56:40 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Niklas Schnelle <schnelle@linux.ibm.com>
Cc:     Matthew Rosato <mjrosato@linux.ibm.com>,
        Pierre Morel <pmorel@linux.ibm.com>, iommu@lists.linux.dev,
        linux-s390@vger.kernel.org, borntraeger@linux.ibm.com,
        hca@linux.ibm.com, gor@linux.ibm.com,
        gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com,
        svens@linux.ibm.com, joro@8bytes.org, will@kernel.org,
        robin.murphy@arm.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/3] iommu/s390: Fix duplicate domain attachments
Message-ID: <YzMrSIGMPSgJ94sG@nvidia.com>
References: <20220922095239.2115309-1-schnelle@linux.ibm.com>
 <20220922095239.2115309-2-schnelle@linux.ibm.com>
 <YyxyMtKXyvgHt3Kp@nvidia.com>
 <81463119aeadd55465cfac1f5bc6a8b79f0c9738.camel@linux.ibm.com>
 <YzGtQY+uw4ZzZoSH@nvidia.com>
 <1a10b5baedafb56335231ccbd585412bbb3a108c.camel@linux.ibm.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1a10b5baedafb56335231ccbd585412bbb3a108c.camel@linux.ibm.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?pUxPZH/s6hRfFD/ZkHg87h4EyKAonW+iDej/h3ji4wWcy1R05atvTTG6+t2u?=
 =?us-ascii?Q?pGmYTlV3cGTHm52xdW6S3/myezQMQD1ZqgyYyHlZn0fLCgIZIVhDp9E2jSlc?=
 =?us-ascii?Q?SocjfXX3Gv6lCpF18iUgmhVaWGBXfwJuwH7Jkyu3z2CmBk6uDH7CU/0WJjvd?=
 =?us-ascii?Q?U0i+Jhi0zheB47QP/ZiIruNE/wl0lkaGxiYeVYrgf+WUij9WusN51Ak34Y+I?=
 =?us-ascii?Q?MrH4Vb0EWrEf2SSoyjNaytV2RasJP5kB8if8jh7qg5PDsx3lHXkqM1TLZNb5?=
 =?us-ascii?Q?UfMfE2W5/ZAAhbkchRjiN+g3CMWNCDIoOJ3nfbBnhEVZna+fN9Ue4hcbzQ9e?=
 =?us-ascii?Q?12Czobe5jfJnjtxko0I4PtVOVUJSjn8zOfWxB91m21Oz6tKJ3EZTPbjbXPO2?=
 =?us-ascii?Q?jusWTrjIL6LkjN57/pema1EQupSwXGHR4IhQtuxE/y1hAQGlLyUnCI/A1xeb?=
 =?us-ascii?Q?vpbZeTDeGuH2L1aO4VYBBYU+BlgS65XS7ssEk3erpbyHVRv6R4Y8S5sOP5T9?=
 =?us-ascii?Q?s9rHRCm6Ch5R+uaUa5QiYPdeNen6cYsBPpIbSrhA4FvuJuArAAWTsX9srBy2?=
 =?us-ascii?Q?AL4NFS3FtEjVyQJbn+IlYYdkQ6VHkM5Rz4xcrQOMMu6AQUCDPgrv6duz84L3?=
 =?us-ascii?Q?203BF7GEsxHBvxQyrxSTaYpuupyv+UC/Ocu0erQHv0bqrfx0fgxt8cB/dfwH?=
 =?us-ascii?Q?j4patEKJJVjFErbMX5/Ui8KUovbeFxuFj4clDXC47lnm5GEgsjneouZ+6hCu?=
 =?us-ascii?Q?dgxLKL5xmlfYXxiqttZpz21BNcc6frB/qvRnOugse2PeECq3pndg7tuPUY3A?=
 =?us-ascii?Q?De7IqX+Cxa6uGlywBHv6mHei+BILPuikXzALkMAYXhKED+n/unb7SrR8gX/k?=
 =?us-ascii?Q?Wjq9l9BUaPjcbJP+M1ca4rKC+Y+c1Ts1qdEhzoQsrO4WHlFrBdiZVB9pO2eb?=
 =?us-ascii?Q?ylTGUDzAU7CjrD3b2WMYtWB/FpD4Fa36BJ+5aAguDkZLEfsoMe7cJIrg3ke8?=
 =?us-ascii?Q?zFst2rnvOMKl8HTrRQcxOvu0A31RzbkNq1OnQi0uFcRgmdcog1JCEwWWeZEY?=
 =?us-ascii?Q?hATS9CKgvEkOLjMuQJaLox9uHmbORHZc9h/FTGMHmesqCWq10uDb/seyxN/V?=
 =?us-ascii?Q?YgVDKTjTAvYduTcVol+wKXrcYFjlerdmt+hfz957UoEhAiwPY0oEge6fwo9E?=
 =?us-ascii?Q?DNqXsvmpcRG7ZvAba4wdhdfjDDhD5AUWZtNq3S5p47bxBbxJIOaZrDPVb+h3?=
 =?us-ascii?Q?HpMuPzzHsi5/rMV+Vr3gNmkLj//Y9JK4mx6X07NOaMP6V0Tnr+QK6dURbodF?=
 =?us-ascii?Q?mbuRO1DeSs5h8GT+0tKwF60tg96KWW4TFj8P+0MK/oMvZfVIyOO3H4SdGGiW?=
 =?us-ascii?Q?HzVJ7EH29vg2BPZQJYiLCPnK8OYy5z8GbxHCJH8Fm5FsR39KF/uCsYM8dcSY?=
 =?us-ascii?Q?0MiVSU2NVNtK5gdAwv8zKR9eYByU/MqtAw+cuxr5bc64sby5B10fkoSe0KcF?=
 =?us-ascii?Q?clh/PGcSonCAXmF+9i3J8oqcCpVExjwLagOKKAZEtj8FCjJaF2ztUcEbpwk3?=
 =?us-ascii?Q?YPT4ffy8djEE3dWIs2Y=3D?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: cca024c5-b2d6-4d4f-bf73-08daa0a9405f
X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Sep 2022 16:56:41.7374
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: KSQ0lNlvaUTW8LU5p9LbepNLLKWAjGzZ772Jx5dNcsURYfwtlhENSQivIhY4HLLu
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB7160
X-Spam-Status: No, score=-1.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_SPF_HELO,
        RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_NONE
        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

On Tue, Sep 27, 2022 at 06:33:48PM +0200, Niklas Schnelle wrote:
 
> Not sure what the non-MSI reservation is for? It does seem like x86_64
> also uses this for quite large ranges.

There are lots of things that are unsuitable for DMA on x86 platforms,
unfortunately.. But yeah, I'm not sure either.

> This is because I'm getting a map request for an IOVA in the reserved
> region.

How come? iova_reserve_iommu_regions() reads the reserved regions and
loads them as reserved into the iovad which should cause
iommu_dma_alloc_iova() and alloc_iova_fast() to not return values in
those ranges.

It all looks like it is supposed to work

Did something go wrong in the initialization order perhaps?

Jason