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Fri, 10 Jan 2025 11:56:49 -0800 Date: Fri, 10 Jan 2025 11:56:47 -0800 From: Nicolin Chen To: Jason Gunthorpe CC: , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v5 08/14] iommufd/viommu: Add iommufd_viommu_report_event helper Message-ID: References: <20250110174132.GH396083@nvidia.com> <20250110195114.GJ5556@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20250110195114.GJ5556@nvidia.com> X-NV-OnPremToCloud: AnonymousSubmission X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL6PEPF0001AB77:EE_|IA1PR12MB8078:EE_ X-MS-Office365-Filtering-Correlation-Id: ff0f744b-0449-4dd7-4084-08dd31b0f554 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|36860700013|376014|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?EEFj22D/JShHoSgD1dfsZJEjT/pBk6XnPg7CWKfiHxXmVq36AE7tzNtzx6wr?= =?us-ascii?Q?5/i5XSx3BmoEPC6GRhrlOgOGZzQgUC3EgvVuPu2TG1sLSp6EiFwIz45Gg/gq?= =?us-ascii?Q?GRsnOpnVGIdZvkytDQqQtvORWOO+n2j4RqIS1axxIJM2HB/SwjM3HDy/WCoI?= =?us-ascii?Q?6Chd4gBqWX6IxiOOUnnOES9YSIhdygu6iMtPQ3Qvj9Z1dtiT0sAmbi9MoUhq?= =?us-ascii?Q?CvHgeU61LWlNE40JFd5Wr8Iz+juiVb1Pa70rFUDjlyKU3oFa4PRIgcWH5Yvo?= =?us-ascii?Q?IemOeFaWNwkMcAGqBEFeKU0r+n89hjptUTwB78w7aQOZzdQ1sw00Znbt+GQu?= =?us-ascii?Q?F2fbOa9yaP/sK+LE9vrFlEOO5AlDRH6pwYRI/QB2gYcWVyM130/d/ocwH4W6?= =?us-ascii?Q?pjQ2M4o+0ln04ghb1U9g+Y1LuI8SQz3B2Pcy1RHpU9rvaWqKx/lL8iMVslYO?= =?us-ascii?Q?4wY231cHU7rG0IXtUDowtKh29uAIApETjYABAFJ25A74bGsSoUE/2hgf8rwD?= =?us-ascii?Q?HcBIqdI1wG02/9fi47UFTVajcFo2kXcHvGNoZyj3dIjrl5gv+1f7Y29u+Qsb?= =?us-ascii?Q?zIB8+3j5gI+GEQwXwTByDwQn4gr1TXwV2h+BOtp80dmpRTQyrfSqQE+ldir0?= =?us-ascii?Q?A9nQfrGAvD8MVSZHVZ3VHgyrmBA1kayORPgEMdJgtvwUZyZwjz9WG4+wKbvC?= =?us-ascii?Q?iTv/V7mBDQVgMioHr6mQJA6uq/W14gs43Ke/5T0+A0Q9BpSyacf/zwli5ZiT?= =?us-ascii?Q?7Z7vrTZEMG16X9ehm5YlcIJ9Gj+0OiQRJczM7ZthovvUhi+kbmKurOJtb7Wl?= =?us-ascii?Q?+fukQkjHYZ6K5Bx1kc/VdoCdqzQnKPR+g49HnR8BGgboakHu0dNo4807HaFP?= =?us-ascii?Q?bIVD5PX5ab5IJwBo0E9PlqWUqIzjbXc5L1bSudlqlL/5djq7QWeUE757jYQ6?= =?us-ascii?Q?Mfs1Dj9b8iv8CMJI2HxvFN7la2XTjwA+SjFJ0OvTHjWS3Wem/BKj7Ji2/scp?= =?us-ascii?Q?4F8B5H6/gsEk56NN1O9JbQXZnvAq1V3kt/YUYpsnwSmcD73yDYNHrPtOKatl?= =?us-ascii?Q?/d9uTEraWgQxf8+uBFF9ynzKkWbuZAmMauVLlmPyi6Gri4I0gdfyjLaxWPCP?= =?us-ascii?Q?d1zkUvxP+JjjThpt8+DuAgHdPP+aTl5LtxXG7wDgwY1UeC7Y3XLuy+jce03I?= =?us-ascii?Q?kgKEM+af3TtzpJLHbbdHFhuSCt9OuyD7FAm/FURyw+iflcqhkttm0dlN6cD/?= =?us-ascii?Q?FJV6IH2OUMs8zk+2UCaZYURnjgd4p+oqoEdMHw6I8auQv1rYScrJRMQS8HFP?= =?us-ascii?Q?yPMBMg20i/QY06f7lZ3UuOFRaPA0RAbsGlNQFwVeL8N8Q2UsOwleWJ4JeV3F?= =?us-ascii?Q?39mxTqvzyl4KLixLbYWVIuRvC8NxlmyYXHodaLDrPrLgbYkzbkQ9KRj+50FN?= =?us-ascii?Q?QcP55xFDkZw00VAO4GORh9wk3F3HFeqgX7bPbTJGspfnFRrvQCg1CAxPla6n?= =?us-ascii?Q?T4Jan5LSklD68y0=3D?= X-Forefront-Antispam-Report: CIP:216.228.117.160;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge1.nvidia.com;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(36860700013)(376014)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jan 2025 19:57:05.4391 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: ff0f744b-0449-4dd7-4084-08dd31b0f554 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BL6PEPF0001AB77.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB8078 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250110_115710_767097_5E0F0004 X-CRM114-Status: GOOD ( 21.74 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jan 10, 2025 at 03:51:14PM -0400, Jason Gunthorpe wrote: > On Fri, Jan 10, 2025 at 10:38:42AM -0800, Nicolin Chen wrote: > > > The virtual event queue should behave the same as if the physical > > > event queue overflows, and that logic should be in the smmu driver - > > > this should return some Exxx to indicate the queue is filled. > > > > Hmm, the driver only screams... > > > > static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) > > { > > [...] > > /* > > * Not much we can do on overflow, so scream and pretend we're > > * trying harder. > > */ > > if (queue_sync_prod_in(q) == -EOVERFLOW) > > dev_err(smmu->dev, "EVTQ overflow detected -- events lost\n"); > > Well it must know from the HW somehow that the overflow has happened?? > > > > I supposed we will need a way to indicate lost events to userspace on > > > top of this? > > > > Perhaps another u32 flag in the arm_smmuv3_vevent struct to report > > an overflow. That said, what userspace/VMM will need to do with it? > > Trigger the above code in the VM somehow? Oh, I see. I misunderstood somehow.. Thanks Nicolin