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Fri, 12 Sep 2025 08:35:10 +0000 Date: Fri, 12 Sep 2025 16:35:00 +0800 From: Chao Gao To: Hou Wenlong CC: , Sean Christopherson , "Paolo Bonzini" , Thomas Gleixner , "Ingo Molnar" , Borislav Petkov , Dave Hansen , , "H. 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?pcuh5vtYnJlspjgjRPRGfHBL27nNU4LZw++4Zh1N6Stj7Uf0rRPVxcUCSEhK?= =?us-ascii?Q?wTfnn4bpXBMS8PecJn4NXNk+L0T8SQzy0irum8pgp9RBUoA5d+KgGRPAZ0ws?= =?us-ascii?Q?LTW2FIWYK/tUgchgel/JLejNSFhclCLA9nJv1t9eWGKLEzJ6opheCsAnBAwp?= =?us-ascii?Q?SkrQBcgcDffNoy9maEY60AkNLunDBktNfLm9liVfLiIvWyS4mkhPNmstW4eV?= =?us-ascii?Q?gJYqI1aeNMQQeC5winzY5n5/L7tf9nvTkrIOFsHB6jJ2pUP4RV2/m4Gnq297?= =?us-ascii?Q?Gy8padiG27i5vkYLVCUeh9xzFPQ/DdlK6mn7TTX9TozY3HhgATlp4lezSeEr?= =?us-ascii?Q?gkv7wY4nVs+yXCZBowR+ZXdJpPfXeKOkQ31iaD5VVtUJSKuCjp/b4EnD4fPP?= =?us-ascii?Q?9a7lJs1H1i0obubaTUdQC5CGtGoz8b59AcN58vLrDkBn/F+PwwvtXX17bpTl?= =?us-ascii?Q?TXKtDy+TR2Ja93EL+Tzoyd+Y3/nBuZK9F0ZbHEU26WVkycyo48eu/XMqEr83?= =?us-ascii?Q?VAQrtqRdcm/59potNNIJKn9ehPhNJPOYMnEHKmefu6d7SbFaBjmVvtyd6twy?= =?us-ascii?Q?b/DUhzLb552nEU2j1qx0pWo+YXmaiuIGyL2J+zUanlaP18Y4IIJae63bizmP?= =?us-ascii?Q?KDnY7YGzE3rUgkRWdk2re4ojPS90QYEIlnvfziF33HeouU2JW33PHsEkjhv4?= =?us-ascii?Q?QWLansePWDVXvmB5PGGKrNdzXyIz+fIPgtwK0F+gvB9lpEEi4FgVJdI8C3Zz?= =?us-ascii?Q?aCfk8xhri7VrkCRYCpq+iidcN8NKZvrpGru3REx809QyIrkihGAX4vNNXcvL?= =?us-ascii?Q?9Y6AyXz59iOj3y6hht1RtnptefVOcUVzolmIiHGVImaJ5QmvlDGuKSO+JDuF?= =?us-ascii?Q?XJ/F8/ZSEZdT6tIhuYH0Jjiep/1+mlo60LgA8YTBmQi1WhAysOCwhGmG581m?= =?us-ascii?Q?rtN/HBv3GswpIc+ufvni7Qoik57PGow8TStGnst3BIIVRoyTvEr8j6mAqCCA?= =?us-ascii?Q?JgPq8u1JfQ51EiIG4YXcCUSgcyLrXWGWMYepoj8Lp3fSF6Z5l9VZjsq75joS?= =?us-ascii?Q?Tbf41i7j40Bbq8i+R+A0J+KB6cjX2NHzkqWM5EIQ6Og+OXcNOxpvXqpqhYyy?= =?us-ascii?Q?TmTNVnqiywfXBA8fIHR+4A3Sn+jOSCucVOE3BXEphOfPtVWyjzBIRy8jIi/j?= =?us-ascii?Q?A2Qx6a8ouVFz1A8a9UeWbGzzA1SzoFcLkPDDSnxa0azqJhg9/lZ3nn1i7UGC?= =?us-ascii?Q?WmgXo5JZKFs8TVduOjhH40V0o7M/zd+/ddCWbRT/Th1p1xP+WwzbJjCMi+D1?= =?us-ascii?Q?lfESNZohnFu/8dEX5pM/aThf3m+wHIo7R6JnpZrqbEpUBtzMQAuQv+sCskAX?= =?us-ascii?Q?grAVHpLw7kVOb9mHTCQ0XWYsBvQbQ4Z+xTjy2NYGx0QTB3mIr3RKohyW0MQI?= =?us-ascii?Q?3b8xSkEQExGRzF/xhtkaJ2JU4F6AgcNX86X21lFrz7N6fmtoOjClCMw8fpJ+?= =?us-ascii?Q?uTcHe1JR/XErGjPJnkUIW+jN/uteT/Vgd9LRdac/X+E1t0L428TPM7dipBlc?= =?us-ascii?Q?r3tW3MuRzUTvyZh8ODFnFqRqG0N5+tGznUHkZZIR?= X-MS-Exchange-CrossTenant-Network-Message-Id: 78add482-bea9-4922-69ba-08ddf1d74913 X-MS-Exchange-CrossTenant-AuthSource: CH3PR11MB8660.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Sep 2025 08:35:10.6121 (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: xyctb42dPEQeEsaeoCHHgOsf+OYG7K5Li6I7g4cGUd2ZSHVc2MpwC4RdXmIjvGK+F6hwb1EDIwlgeqpgzJFk9w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR11MB7646 X-OriginatorOrg: intel.com On Fri, Sep 12, 2025 at 03:35:29PM +0800, Hou Wenlong wrote: >The commit a377ac1cd9d7b ("x86/entry: Move user return notifier out of >loop") moved fire_user_return_notifiers() into the section with >interrupts disabled, so the callback kvm_on_user_return() cannot be >interrupted by kvm_arch_disable_virtualization_cpu() now. Therefore, >remove the outdated comments and local_irq_save()/local_irq_restore() >code in kvm_on_user_return(). > >Signed-off-by: Hou Wenlong >--- > arch/x86/kvm/x86.c | 16 +++++----------- > 1 file changed, 5 insertions(+), 11 deletions(-) > >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >index 33fba801b205..10afbacb1851 100644 >--- a/arch/x86/kvm/x86.c >+++ b/arch/x86/kvm/x86.c >@@ -568,18 +568,12 @@ static void kvm_on_user_return(struct user_return_notifier *urn) > struct kvm_user_return_msrs *msrs > = container_of(urn, struct kvm_user_return_msrs, urn); > struct kvm_user_return_msr_values *values; >- unsigned long flags; > >- /* >- * Disabling irqs at this point since the following code could be >- * interrupted and executed through kvm_arch_disable_virtualization_cpu() >- */ >- local_irq_save(flags); >- if (msrs->registered) { >- msrs->registered = false; >- user_return_notifier_unregister(urn); >- } >- local_irq_restore(flags); >+ lockdep_assert_irqs_disabled(); kvm_offline_cpu() may call into this function. But I am not sure if interrupts are disabled in that path. Documentation/core-api/cpu_hotplug.rst says that callbacks in the ONLINE section are invoked with interrupts and preemption enabled. >+ >+ msrs->registered = false; >+ user_return_notifier_unregister(urn); >+ > for (slot = 0; slot < kvm_nr_uret_msrs; ++slot) { > values = &msrs->values[slot]; > if (values->host != values->curr) { >-- >2.31.1 > >