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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?vS76w2jkPrKgztzSjnRvOQOiEvakwAYlSelT54Dfzjq8rgp9DGDYca6JRpBy?= =?us-ascii?Q?CEz0AppNW592oKDbXpwdfphdXqafy+3R4/GLKjuC4Tndy1TaIAyMfOJlH6Zg?= =?us-ascii?Q?fsXpR/A1Y9bJ0DJ/OGyqeQPfRpE3XpXygEJr9xKhoIaUuYxw6u7O0icL/4Zt?= =?us-ascii?Q?fPLZE/1kp5coiLdM1j+N4URB0kB9QR4MUvY36zpeabW+rh1ocxwZcB3RSQrd?= =?us-ascii?Q?Gp6UftYxDiZNaVoy6L383IKpwqB6rTenWUCJ7W7+NQk2Pw6E9xpsQuqUK898?= =?us-ascii?Q?dk2l9gG1fDrAlsZrY56YSOPV4dNBXh9pvel6zcxpC3bgCgGe2qDjbrkTq1ff?= =?us-ascii?Q?0B/uNq+2CDo6M6d1Nebzggf1hRSxFlkH0gmLPN8Dus+bLd4gOjy1ZWfhUjY5?= =?us-ascii?Q?U28UjR7TYk+qlA4ezDUMPvItxQkdhCT5i3/juFluewj5bwNNTi2HgmDj4LUl?= =?us-ascii?Q?nZU39pqIhGnKDDpmsqTd2Z53f8wwJONuZsKH9oI4I2WCos3ahvJbsHJjHYly?= =?us-ascii?Q?QBecGTuG/IG3uZEb81F5k3TgVm1N6xF1BLakKFukWlUTbOMMdGpkEE8MX4ul?= =?us-ascii?Q?cPsm4GeIOnUQVHofGRH2LJdgkppQ/j6b7KP59ngsMZvLfv32InAcXzix/CLo?= =?us-ascii?Q?iSlMGZYXGpBcwUzl9csnBORwtX1eihDuV0FRN/Mfu4PaaGrLjle8QpJMkjrF?= =?us-ascii?Q?EVANIKZlfKdOVk7lojZDpXjXZBLHx7HkviwrCVwO3y1YHg9KedtBtZ7NnAGc?= =?us-ascii?Q?V00/3XilvA5OvS4Sm+WQD6F2U72ChNVVerfm7Wl3sfm39AemmzcDpcME84Ma?= =?us-ascii?Q?FxHeGEr3x3OqdvP38OjVze5itrIwDh1RRCmFW4wfUq2s+Urfke+GuNVl6Yqp?= =?us-ascii?Q?z4hEOw7UAU96TO49tTyd3pd5ieSP3hvBXfADO+fYdumVYZbceRy3O/HaFzrx?= =?us-ascii?Q?lNW1Ke9aM0BRfVRS5dsCmzuwsciBQBA75U6Vw6kADAH7S8sHt83481MfyhOd?= =?us-ascii?Q?HIXqCrMMqDxUWmAEIlfzGfpbLB3sFeZ8LU7yPl3BJZ1/s8I/CqT1sqhDCTEE?= =?us-ascii?Q?8YBL1d+VpAIVqhCu1jJ3hA3bxXZrR6t2IL2jmhdNtpouv+p+IDvw9LDBzcXZ?= =?us-ascii?Q?ojbsZW3o/x3EdF74ENyYz9BLigbsF6/uplyD9S1o03v725ECUiXq5fKgx5H7?= =?us-ascii?Q?ei8oCyxWenGnR1jEnT0cycnV2cPMyqbG8NwBn+n37hu7xIXN7pkt4NjBth02?= =?us-ascii?Q?M2j/vh5eiHkX/1qMPpcgZKzqSEyjsAkbQbi11a3oPD14hyMRjj5AxaO9IRLh?= =?us-ascii?Q?pa+qfxSPiAE2xfE2SRzmDBM5Zk7cKFvWlzU0zomx/kpmo5sIJEf1GJtXoYP0?= =?us-ascii?Q?rZpnj8sfc8hQ19Gt/X+qLeFTjnWHOOFlDvFvtRREhh2LEHT8YSh1PB/k2zly?= =?us-ascii?Q?OncGkqxBehwZlPzpoHGKKRHtHaFPD5T28JPQS6sydKqYT1G/YjrTkgUspaME?= =?us-ascii?Q?Rly15hAWOvlpoNJ0zOBKW7IBsJGySgPGKUiEIZmYZeyJzQ5zk5cPX+DH7rxd?= =?us-ascii?Q?drOJOH0kb4wNQw5MRYHjenZ34UrpwQ8YfVG9/qmZ4+QMnYCn0F1XRiKIR6eB?= =?us-ascii?Q?GA=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 2d094f65-1f08-4d6a-9b0c-08dac2c46f6b X-MS-Exchange-CrossTenant-AuthSource: DS7PR11MB5966.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Nov 2022 02:36:56.6453 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: IKb5JfPfoB+7HMFtDGyOlMIYQ7Mt93FfeLVXm9MZFMHVWYkkJxvmCy7pomVoXgyLVRfxgF3TmmlT811+6TntPw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY8PR11MB7033 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 10, 2022 at 01:53:47AM +0000, Sean Christopherson wrote: > On Thu, Nov 10, 2022, Yan Zhao wrote: > > kvm_prepare_memory_region() is not useful for KVM_MR_DELETE, > > and each kvm_arch_prepare_memory_region() does nothing more than returning > > 0 for KVM_MR_DELETE. > > This is not true, s390 has an error path that fires in the DELETE case. > > /* When we are protected, we should not change the memory slots */ > if (kvm_s390_pv_get_handle(kvm)) > return -EINVAL; > > if (change == KVM_MR_DELETE || change == KVM_MR_FLAGS_ONLY) > return 0; > > > > So, just don't call into kvm_prepare_memory_region() to avoid unnecessary > > error handling for KVM_MR_DELETE. > > Even if the s390 case didn't exit, I would still prefer keeping the code as is. > I agree that a "dummy" call is somewhat confusing, but skipping the arch call > for one operation is equally confusing and could easily lead to future bugs, > e.g. if the order of changes were reversed and an s390 developer wasn't aware > that s390's arch hook would be bypassed on memslot deletion. yes, you are right!