CVE-2024-43819

In the Linux kernel, the following vulnerability has been resolved:

kvm: s390: Reject memory region operations for ucontrol VMs

This change rejects the KVM_SET_USER_MEMORY_REGION and

KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM.

This is necessary since ucontrol VMs have kvm->arch.gmap set to 0 and

would thus result in a null pointer dereference further in.

Memory management needs to be performed in userspace and using the

ioctls KVM_S390_UCAS_MAP and KVM_S390_UCAS_UNMAP.

Also improve s390 specific documentation for KVM_SET_USER_MEMORY_REGION

and KVM_SET_USER_MEMORY_REGION2.

[[email protected]: commit message spelling fix, subject prefix fix]