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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?KsuwPF6k0Gk2w8l6XA3gVmKKtEoPZfivgpdC9xCTOz3duO6+jrA1jaskVdlu?= =?us-ascii?Q?GpewiUrd29Ut2OD+xSR9KcUBDHbaE2+mbYJormyQ/zN1uOGetYrnFEca0zpo?= =?us-ascii?Q?b4Ldx6Ct6QVHrFLGhKiL+7W9XHKCsh0ajEYhxcpoPNqs8ZxYo+Bd4tpBSHfX?= =?us-ascii?Q?zWDz3dZeEUzxIinC39/J4GOOF9AI5Seznc7gA22pCN9WoHXE3K60/lmovXgr?= =?us-ascii?Q?xEMLRwESZRGZtllEJyRiSAvd5gK7PKal/NBVBYF9VaiNgS6YcJ33UNMuLrxt?= =?us-ascii?Q?9UpjTRm8AwipdoQFQ+Io/OTOouETHdjgnuJBnBJ/PakkoiHh9DnzHw5Th5n5?= =?us-ascii?Q?V5OhCK9PFFS0nzhwbSEP7wdIvdBzoU9nGRR+DDXd2XMFUWZMGaOG/9sHeTV3?= =?us-ascii?Q?jlU5pQ69n3ISLcPNlmcIE0FWn2oQvr9pqrcAwK4TDoOiTQR0+8Np+HGeDzb5?= =?us-ascii?Q?K6M8WhagJibo/EmSXK6IDnL6jPlJOKmFjrg86rmQ38qqnWWeuOdjCb8QRfA8?= =?us-ascii?Q?SDU7maQZHnKGjofs0gHnuUSlxLNH9msB7S6NGs8qUKexv+9kVPaUf1y08Xyi?= =?us-ascii?Q?pIuKc0QEmFrU0kpjspY6rv9HFlHyLNGKuXA70+FSimRTr/ON33pDDhxlkMsw?= =?us-ascii?Q?U8ACgvXf1gxknrC9n/PcwQFYI55U+qiNbvQLClSolSrNjfqgc+kF0TOsczn/?= =?us-ascii?Q?qiqExaKoAiT/FxTHD4ELJRJvvb32ojWNWcZ+8Zpxsrfs2glEACA9zknE3KxH?= =?us-ascii?Q?45E4DKyVrDR0FkrxJ5dquDgTyYrtzntBUNqXiqPDa+o+Weoro3Csmo0D1cGq?= =?us-ascii?Q?WJfx70ZaFtr/yQDoyNH8Als08NGn7Zhcoeo4zd9KoBzfHW4K8tDFdBVu27zw?= =?us-ascii?Q?vVo6qYDmJycm9Xqq0XwQO/Bl66lMoT+o+hiXCZj8SVwv6+svC2+TpqVce0n7?= =?us-ascii?Q?CVvv245sdJYuyfB2pYACWTE18r2hVcLeVh2MLox5pjxeDBjjhSRhfquclSIG?= =?us-ascii?Q?jcE42CFwq8j5cRw73B0Rg32s/cGQn9m2lf3EAXqNuT1di79RaELpuYpjDjgJ?= =?us-ascii?Q?pCIR2zekDWeYCdD5FpWuGGqXlW3ZaPw3QCTiYwExpGWEZyakdSeDORjWK/hz?= =?us-ascii?Q?AFRi2UupEeXQzt2IJgRgJyr8VjJbcXr6A7utOyq/Gq5exSaONgQXeTW2TjIU?= =?us-ascii?Q?KuzVIoHiVU8ELYRAa4MT5QJ1GuA9lfDxw/F5kyg2D+Y3iBJ7iI4DF+gJ1ItA?= =?us-ascii?Q?yLLOlzvKvSFu/jttrf928AB5YERHXIW6Vpq/2gr3dDvIRtVJwK/Tlqi+LiKw?= =?us-ascii?Q?78OvLoeGVTvwBm9RBC6IJCM/CoblTLI7aVkzzLkgsL9YU/PQcj+lfxgYaG8h?= =?us-ascii?Q?sl+RtWJuTA8bWVnt5Lv1EfNxlfR8VuBCKojQBDPdaRpInsSXn78aR4NwW94s?= =?us-ascii?Q?WHKpLevrxslaztcTaH/EXDDqOU0hrsyCQ3Loqo5vjwzlPTtESRXit8DXmDJ5?= =?us-ascii?Q?GpA3CYqFKUiduhKrPV4sGi/O6VTq2OfHMzmU2ANQ5TnpluRnrA70HtxDM0Sl?= =?us-ascii?Q?9Wnnd2+yfmQS/57EZ3azAYJ/9conSKowgxnEvTxQ8YllCZAJuCTllrXCuInL?= =?us-ascii?Q?kVJmJUvOyER7lqSF91v/z8BOXUirjbY1e74tF7xxC2d30LOYZf0zpuohcL9X?= =?us-ascii?Q?Tf4YUNTZidVxkpQgms5D0xYq6yV6iuNyE5w5tcoBZNx675xQvd8SS5ItDhfx?= =?us-ascii?Q?1FwarTq+QA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: a5ed12c2-c2f4-45a6-3e55-08da43f47bec X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Jun 2022 17:30:55.8225 (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: efltRMaVMycoogPM/4gUWnWzlSetA9L/SoDKmyevzPmyO+EDNGRbWRXgToesi6we X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR12MB2677 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Jun 01, 2022 at 10:21:51AM -0600, Alex Williamson wrote: > Some ioctls clearly cannot occur while the device is in low power, such > as resets and interrupt control, but even less obvious things like > getting region info require device access. Migration also provides a > channel to device access. I wonder what power management means in a case like that. For the migration drivers they all rely on a PF driver that is not VFIO, so it should be impossible for power management to cause the PF to stop working. I would expect any sane design of power management for a VF to not cause any harm to the migration driver.. > I'm also still curious how we're going to handle devices that cannot > return to low power such as the self-refresh mode on the GPU. We can > potentially prevent any wake-ups from the vfio device interface, but > that doesn't preclude a wake-up via an external lspci. I think we need > to understand how we're going to handle such devices before we can > really complete the design. AIUI, we cannot disable the self-refresh > sleep mode without imposing unreasonable latency and memory > requirements on the guest and we cannot retrigger the self-refresh > low-power mode without non-trivial device specific code. It begs the question if power management should be something that only a device-specific drivers should allow? Jason