Re: [PATCH] s390/kvm: Reject memory region operations for ucontrol VMs

[Paolo Bonzini <pbonzini@xxxxxxxxxx>]

On Mon, Jun 24, 2024 at 11:59 AM Christoph Schlameuss
<schlameuss@xxxxxxxxxxxxx> wrote:
>
> This change rejects the KVM_SET_USER_MEMORY_REGION and
> KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM.
> This is neccessary 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.

Would be nice to have a selftest for ucontrol VMs, too... just saying :)

Paolo