KVM devices were manipulating list data structures without any form of synchronization, and some implementations of the create operations also suffered from a lack of synchronization. Now when we've split the xics create operation into create and init, we can hold the kvm->lock mutex while calling the create operation and when manipulating the devices list. The error path in the generic code gets slightly ugly because we have to take the mutex again and delete the device from the list, but holding the mutex during anon_inode_getfd or releasing/locking the mutex in the common non-error path seemed wrong.
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| @@ -1113,6 +1113,12 @@ struct kvm_device { · 1112 unmodified lines | ||
| 1113 | 1113 | /* create, destroy, and name are mandatory */ |
| 1114 | 1114 | struct kvm_device_ops { |
| 1115 | 1115 | const char *name; |
| 1116 | + | |
| 1117 | + /* | |
| 1118 | + * create is called holding kvm->lock and any operations not suitable | |
| 1119 | + * to do while holding the lock should be deferred to init (see | |
| 1120 | + * below). | |
| 1121 | + */ | |
| 1116 | 1122 | int (*create)(struct kvm_device *dev, u32 type); |
| 1117 | 1123 | |
| 1118 | 1124 | /* |