Merge tag 'kvm-x86-asyncpf-6.9' of https://github.com/kvm-x86/linux into HEAD

Merge tag 'kvm-x86-asyncpf-6.9' of https://github.com/kvm-x86/linux into HEAD

KVM async page fault changes for 6.9:

 - Always flush the async page fault workqueue when a work item is being
   removed, especially during vCPU destruction, to ensure that there are no
   workers running in KVM code when all references to KVM-the-module are gone,
   i.e. to prevent a use-after-free if kvm.ko is unloaded.

 - Grab a reference to the VM's mm_struct in the async #PF worker itself instead
   of gifting the worker a reference, e.g. so that there's no need to remember
   to *conditionally* clean up after the worker.