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 15:36:50 -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>,
        "Ahmed S. Darwish" <darwi@linutronix.de>,
        Reinette Chatre <reinette.chatre@intel.com>
Subject: Re: [patch 22/33] genirq/msi: Provide MSI_FLAG_MSIX_ALLOC_DYN
Message-ID: <Y3U70tdfYC+dFhts@nvidia.com>
References: <20221111133158.196269823@linutronix.de>
 <20221111135206.521387616@linutronix.de>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20221111135206.521387616@linutronix.de>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?55mtJrgh0vwMQlGlJXN+Y6IcIS8U4A04YcNv8PUQFLxzfy2ALGofoP36Qm1y?=
 =?us-ascii?Q?Lv5wdlZdXvE7oQJex0MM8+nurtnGHaw9PcFsVWlid+TSxTf4121jcgzN2Hj1?=
 =?us-ascii?Q?xiORGp0rhki2KPCrGau6NlrgHl3dV4dQ5Lbunkj3J40CE5nZHLyWlqwnEEir?=
 =?us-ascii?Q?BQ3C/5yXHwC58FZjpBOBrS+ykli7GPblhMCJYdmNo4JlFSmLEV/mrmBGLNnN?=
 =?us-ascii?Q?K1E5Z1KrCNADI0UiFeV8qQivndG0aBdnsZWE7fhWZJOFZpgBeHKxCZA8H6E0?=
 =?us-ascii?Q?WEaq0rhHh7yG7379Wyowb2Zt+a9BqRRdHwpp//1OBOCUZH4hK0dFDf3tGJGW?=
 =?us-ascii?Q?Dp4BL/bhp0cse1/WmkVJYyjg0eaz5MKuBiyeKC0BKHauvbn5DV6Cgpw6X5Jc?=
 =?us-ascii?Q?QICiMGh6yWABz2MIFbP74HXBcyhSGqGY/AVZEvCc6/YYCd7xM4qAUorRwCxL?=
 =?us-ascii?Q?7DPVQkOa0qqoyK6pJDgdARX3JMMuPh33jNWumIsf3HpqRWYZ60gCIIr57YNd?=
 =?us-ascii?Q?4Yxvoho2rT2UhWZcVaLwfzY+PzdT0RrcfqbD+JDX8dvyzD78h83F8r3qMqcv?=
 =?us-ascii?Q?eaGumH0C4pafog/Icut8V22Ojo7q3FgP+Kx5/REQ0MxZp2QiN+Ksi15GOOUx?=
 =?us-ascii?Q?KOvuBdw4oKquWnX8mlUrUFZA8MtTZ+/kZbfEL1rVGEk3ywXYCpmkRjkEL1mL?=
 =?us-ascii?Q?ASiVkqnt9DBjYNJde7i7Stxf5XHWfIvrPg9I7n5ZseIVZ525VE/hLXHGKQVl?=
 =?us-ascii?Q?AYE5ZFM4bDZM9Fg5v87RtNC6t9QvVEbQex88eMx0BmoJC9uwPCOwKm5vgxA8?=
 =?us-ascii?Q?KOnzapD5GNj8ItFsvu3ajuQCreMwT0aeI860n5FTykaEF5qMbWTD0zaMDXwn?=
 =?us-ascii?Q?qvqVSIqe8QHPJdDlciNu3h1AXTxdiEpQDQxVSZh3A5Gv+qvZt2BLZTJs5kv+?=
 =?us-ascii?Q?0Ke34EBnXQAsEnNrcx20CkVPU5/GE6xlh3HAce/h17/PRFqx9kawd35E/xDR?=
 =?us-ascii?Q?l4fOI9kh6AJZ1Zt+mFEn51U7Q/CLeiqQBw+eXXxy7tznkRcLaQGD6DbOdkX/?=
 =?us-ascii?Q?dhVcTjViOTV2EQeiKYKJ6CyVU/NXHAzDE+zKHmLjAQnRKWJHpZCg8LYUSAkk?=
 =?us-ascii?Q?UHZhGlvA3BRWPqkv+x5VH2lsTNYBTXkrgBDB+dBpMG7wzA59AAgE6Bh7L4aJ?=
 =?us-ascii?Q?16oOw6HbyL2lH9o3P8+OXum2QgN5Zm/MICKn7YytQBIHxtIOcVUJiQfN0mMv?=
 =?us-ascii?Q?+ZagG/XjqxE8hcG4rAUZrNzXolIw1yWnntZ+tqZv+ILNfamr6TalYum4izOp?=
 =?us-ascii?Q?MFS9A2MVJEVQXjbcVVC+8bXNqjES1X8ORkxTCqOEPQXIXgDRBM+9H4153kpd?=
 =?us-ascii?Q?yyFw2lwBzwddzZt1Bd5H/1mmaNvwm+v806nCaRS0dTRqQDh9PbZFjHgldktt?=
 =?us-ascii?Q?j8MfDHF0U/8yzfXnKpohLI4JruD/4DQRBesip5s29Ul8Xh5+ZxeAK8Gbil/I?=
 =?us-ascii?Q?eId3tOajgkND0qEBXv9VUJzMRCIfTuVUzFN0UuS4CiHjHCnL0+tf6Np0Y2jW?=
 =?us-ascii?Q?/xtGuR4SswV0vz/O1A10C/Lr8TBpCl9D9gotWyHc?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 09a094f8-f5a3-4b5e-330f-08dac809e8da
X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Nov 2022 19:36:51.4952
 (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: yjh6IACIPMLpWSiT4xaGw5ZoG7xZqKk5RGN9WrlowifqULh9O7PSvBbvqan8N2Ni
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN9PR12MB5273
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 02:58:46PM +0100, Thomas Gleixner wrote:
> Provide a new MSI feature flag in preparation for dynamic MSIX allocation
> after the initial MSI-X enable has been done.
> 
> This needs to be an explicit MSI interrupt domain feature because quite
> some implementations (both interrupt domains and legacy allocation mode)
> have clear expectations that the allocation code is only invoked when MSI-X
> is about to be enabled. They either talk to hypervisors or do some other
> work and are not prepared to be invoked on an already MSI-X enabled device.
> 
> This is also explicit MSI-X only because rewriting the size of the MSI
> entries is only possible when disabling MSI which in turn might cause lost
> interrupts on the device.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  include/linux/msi.h |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

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

Jason