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:   Wed, 16 Nov 2022 13:59:14 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>, x86@kernel.org,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dave Jiang <dave.jiang@intel.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        Kevin Tian <kevin.tian@intel.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Ashok Raj <ashok.raj@intel.com>, Jon Mason <jdmason@kudzu.us>,
        Allen Hubbe <allenbh@gmail.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        linuxppc-dev@lists.ozlabs.org,
        "Ahmed S. Darwish" <darwi@linutronix.de>,
        Reinette Chatre <reinette.chatre@intel.com>
Subject: Re: [patch 34/39] PCI/MSI: Reject multi-MSI early
Message-ID: <Y3Uk8lKAgKU5a63r@nvidia.com>
References: <20221111120501.026511281@linutronix.de>
 <20221111122015.574339988@linutronix.de>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20221111122015.574339988@linutronix.de>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Q8WbrBikBT5AL9xNxcRJz7EnatzFzk/CVlf8RwOwtnwrfzaLkiShDU4t8tKV?=
 =?us-ascii?Q?d+5wVo5azOnaWL9PChOHE+XgLEdR8qlBConAPDwEhW3+Qn8proMt0torPgab?=
 =?us-ascii?Q?2NQXsPq941Qt1HpXHam16pp5anNRAhujQQmKUWejOzrAKELDi73+XhVbl/JY?=
 =?us-ascii?Q?BeDedAqAAzZQ2qhvmFXZW7V2/DpiyiZoYftBeE7Btm0EUhBI8Uus4tn/yvW0?=
 =?us-ascii?Q?FQfAdu9Hy4U37F7siXSozbMYmvC2FLJADX/W/bEr6qYbm4Ujj6qM/mFvrSZw?=
 =?us-ascii?Q?OYg5QaEzgyQDW4ybJbkykoGtDlwuguMc2qBpRLbh+t0PawNmeAyG6/FRthUf?=
 =?us-ascii?Q?ZN5FSuy7gwVds/y0eKq+mRIFn5oFpPlByUjuN7gTjw5DtNhceqneG/vJEkz6?=
 =?us-ascii?Q?60BVZa3Emw1QqmzDClMHOBH24d5g3NGZOVLmBJJP6LB2mWb/+TNJpC0FuA+7?=
 =?us-ascii?Q?Xe8ql5eAy3GLcqaOntZnxy5Cf3amcTwNbj7FSrgWCdhQ6HtL5j+zZDhQTA2g?=
 =?us-ascii?Q?dtEOoRX4Qo/vA2dtR0Hdi0Oz4+IqSUV7d1m/D0I11t4Cbu2rtONXjDedW1Zq?=
 =?us-ascii?Q?ujbMgqJvAD0wO9X7okfVVIt2afiCQ+ZFaNcUBsMYXAjimE/GdMeYwU7tEKnC?=
 =?us-ascii?Q?uInuwP2kaCby4xXA9N/8nNDmuBN6TISK17XHwIAACLSlbz3pL6Oa6sA2OlXs?=
 =?us-ascii?Q?I9TqA5Msay4lo+8mU1WTIWomu2zt+f1XP+6oRzY3x4Q500w54jtLYDhsz1X7?=
 =?us-ascii?Q?Sn21XwdWxjj08IPtOVRb9SS7cUpbkzQbZkALiWNwOVLoLGSiOxP2lQhhKmsl?=
 =?us-ascii?Q?PHDp8XuEGjvuDRvgNR0em5E1SomVwRLWHz6SOKiR4zfWTZaDW0Fpp7fu2SAd?=
 =?us-ascii?Q?OTEdK5fD/A2bzaSjNmLb5xAipf1ymKbseAmhdtoZo6Uy17DEVu0jIm7LbpOI?=
 =?us-ascii?Q?oDGD1w7XHK0k5Rife+E5tCnRQZpaS/qjHnyBe+fghEqRa3IFk8bYiMtNQK8W?=
 =?us-ascii?Q?meuNErT1FRSNE20Y68wvd/7IWURpPXwPlK8B5PU0D6tV/wGCBugV9JmUdquE?=
 =?us-ascii?Q?pDYEbTLOlMb2W/FFsOgL8fRlQKQ6YmCkd7XSoYlf5jnzQmwaFO/lCSrHkydL?=
 =?us-ascii?Q?FI3pBHbHz2XoZIvg6cW7N1D5bpqVYsPH1CoGZVTU6n5qlEKWpVM60ee3mxCo?=
 =?us-ascii?Q?0QCoH96MUEdF0Kt03nmzYWjJ/IeCHB6BvxrETRUKHDuhgjpK4+IR8YwdZ3IF?=
 =?us-ascii?Q?3VxkhOMu+wjXTtsGxBWL60fiE/myOHHL4GjWHVSJlvWtihUKfEuB5vM9RMp2?=
 =?us-ascii?Q?AS9XWDGI5MApOrJ6hoEI1p6Dh0BU5GElQUE8Z5Mye1l3GDTra4msqiWA5wX5?=
 =?us-ascii?Q?EcelHZ99Pdkm/fTkrtg0eJU4JysEpvG+TC6f1mTVf0pRw1R1BcY7Adpuv5IE?=
 =?us-ascii?Q?PqZSprMaeQfsBvi2dB+27vscc1uR+AN9D03i8E37v1ycAvlrYX6dr6nwmwXu?=
 =?us-ascii?Q?rb4xp4ZkqYGpTsDLR+rzy+fSHFemAgLwwe+NYB/VfZpgCk2eb+7sQAn/qER5?=
 =?us-ascii?Q?PoniroIK7HX/qsRC0YDVg78tmkva1AfDDLomdvq0?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 1362aa48-e76e-49fb-deff-08dac7fc46bf
X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Nov 2022 17:59:16.4636
 (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: TqHzwiph/bKdLpxpi/hxBDnDwZuFTn0dnXMZ5sPfbZSF+SKH4rIgrN5RTNpPd+H1
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR12MB6526
X-Spam-Status: No, score=-1.1 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 Fri, Nov 11, 2022 at 02:55:09PM +0100, Thomas Gleixner wrote:
> When hierarchical MSI interrupt domains are enabled then there is no point
> to do tons of work and detect the missing support for multi-MSI late in the
> allocation path.
> 
> Just query the domain feature flags right away. The query function is going
> to be used for other purposes later and has a mode argument which influences
> the result:
> 
>   ALLOW_LEGACY returns true when:
>      - there is no irq domain attached (legacy support)
>      - there is a irq domain attached which has the feature flag set
> 
>   DENY_LEGACY returns only true when:
>      - there is a irq domain attached which has the feature flag set
> 
> This allows to use the function universally without ifdeffery in the
> calling code.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  drivers/pci/msi/irqdomain.c |   22 ++++++++++++++++++++++
>  drivers/pci/msi/msi.c       |    4 ++++
>  drivers/pci/msi/msi.h       |    9 +++++++++
>  3 files changed, 35 insertions(+)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason