Re: [PATCH 6.1.y] kvm: s390: Reject memory region operations for ucontrol VMs

[sashiko-bot@kernel.org]

> From: Christoph Schlameuss <schlameuss@linux.ibm.com>
> 
> [ Upstream commit 7816e58967d0e6cadce05c8540b47ed027dc2499 ]
> 
> 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.
> 
> [ Backport to 6.1.y: omitted KVM_SET_USER_MEMORY_REGION2 documentation
>   because that ioctl is absent from 6.1. ]
> 
> Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
> Fixes: 27e0393f15fc ("KVM: s390: ucontrol: per vcpu address spaces")
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Link: https://lore.kernel.org/r/20240624095902.29375-1-schlameuss@linux.ibm.com
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> [frankja@linux.ibm.com: commit message spelling fix, subject prefix fix]
> Message-ID: <20240624095902.29375-1-schlameuss@linux.ibm.com>
> Assisted-by: LLM
> Signed-off-by: Artem Dinaburg <artem@trailofbits.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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