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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Bwrcktxy1p4mv4iGWOVlza8pQhl1I8NRcz1JLp0Ri7A+vz3vKCvE5ExYmwkf?= =?us-ascii?Q?rdREx8HbT6VlIN6zJMuzqL4Rx62Sw978FvXOK1BN2Ene7pBZuCqMUteuJtvR?= =?us-ascii?Q?EsMdbKLQPLFmqAgQuVjN3Z70jmAVypiQKigzCpztjpYXJmd5vobrCwTMImGl?= =?us-ascii?Q?qoOHpGipBHUZLFbB6Z7/gBDY0ozd5/AA855LPuFt4BSkK/Vj3+rX5Aa9U/im?= =?us-ascii?Q?ZDyJ9StpM07dEXIuiJAF4SMOXxDo6sGnE4puqbc7v3uIzUry+jvuaA2xAIKZ?= =?us-ascii?Q?AIVpN9SAD4EAH+IFV3QaIVGDuP/qMTGXZpW9MNQ03t1tJ/BDHPKNYCRGc7cO?= =?us-ascii?Q?M6+IccURRzPmLgqKKaUifRxJqgm9nNWVNVlFl8W9HeOSdOfGovNYongzZf+n?= =?us-ascii?Q?ed8FVTQpGNi34nW3A2DarqyXd/70Uztksacc4q+ZzU9hmwV99/X3Cj886Uhx?= =?us-ascii?Q?b2C1PanCxZekD/5WLn2XRIku3mWUzHOh3CzNFtvjz9SxLIlfbYPyTHoTlQQY?= =?us-ascii?Q?P+xOhA2lt6IVT6Q1OsEPfHuFC4LV3h1VfyjoXGGttfItMNs5fk3zY9rzVszG?= =?us-ascii?Q?fqrVh6k1fk4kGtBRcp++i3J6G2/6eG/CUO+j0L2/x/pnKGR5GuEtN9trm5Ce?= =?us-ascii?Q?bLTbxCZIUIhDFFxv3LvUmJCycwr64uCq4S+7iHrLa0VoyqgTbnAxPXBBwG15?= =?us-ascii?Q?7kxLHWzwdo4n6UCVyLwkZbDhzjh8d0R7s78DGs8F45Poqv9jrIMQGq6tjoTD?= =?us-ascii?Q?5JtL/W009cs0T+UdpOM4Z5goy0RkvSjVu2QY5QWV/oAmeknuK/CkvmoMdVT4?= =?us-ascii?Q?9VBFZceFF7TXl1kljlDlXfERM4B1CVWvTS7dtIgWoISIja0IrHN6omUjKJWl?= =?us-ascii?Q?+VvPHXcIjW84LzUAVP2Nd7DfgsN46x49Mkho3m8q6R7oaz7lB0MlDaiK1+9G?= =?us-ascii?Q?4iVYQU6P+u6cTGlLBcAUNaW0Ai5dJCGKtBxYVoKyJ32OiWOqMfvuzU2FjcO0?= =?us-ascii?Q?ld8DFnFfyvufXblp/Y0Lw1NPjEpIrCfsFYuawXOutkrPn7k0tOcEw/HwsOBF?= =?us-ascii?Q?jpQ8sICu22T1fVjfHaJ2vtux1fVmDCa3GFK/q80AhtUXHv7K0aCLg9YrOhUK?= =?us-ascii?Q?liRAgxj4kSmugCzanvfn+PYROFOT8nVHbKeuDRlKZyrpQyF9/c35AziFiB5V?= =?us-ascii?Q?pmwxv1RvtNI2dSfa15JpCOnaDvCEtVEHteWTR3LC7/XfLmNBNjCfN6DfOGE8?= =?us-ascii?Q?ujV6hoiCdwEx4HWFD9u7V6/RguM5By4gOjM3LDMCuBg7Es81O77NlbgFa6AY?= =?us-ascii?Q?jGV6s1mWbH13iJg/SwIYwwI2?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 07437728-a578-4cc5-322c-08d9328735b0 X-MS-Exchange-CrossTenant-AuthSource: BL0PR12MB5506.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jun 2021 18:30:55.5137 (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: hpZez7GP6TBjMAQhplmzK2HutAeRmEfU5AKQIHcen60tSLS60u41jG5ZvW2F1/LE X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5208 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 18, 2021 at 07:03:31PM +0200, Jean-Philippe Brucker wrote: > configuration. The Arm SMMUs have a lot of small features that > implementations can mix and match and that a user shouldn't have to care > about, and there are lots of different implementations by various > vendors. This is really something to think about carefully in this RFC - I do have a guess that a 'HW specific' channel is going to be useful here. If the goal is for qemu to provide all these fiddly things and they cannot be SW emulated, then direct access to the fiddly HW native stuff is possibly necessary. We've kind of seen this mistake in DRM and RDMA historically. Attempting to generalize too early, or generalize something that is really a one off. Better for everyone to just keep it as a one off. Jason