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Commit e1e8a962 authored by Janosch Frank's avatar Janosch Frank Committed by Christian Borntraeger
Browse files

KVM: s390: Disable dirty log retrieval for UCONTROL guests 



User controlled KVM guests do not support the dirty log, as they have
no single gmap that we can check for changes.

As they have no single gmap, kvm->arch.gmap is NULL and all further
referencing to it for dirty checking will result in a NULL
dereference.

Let's return -EINVAL if a caller tries to sync dirty logs for a
UCONTROL guest.

Fixes: 15f36ebd ("KVM: s390: Add proper dirty bitmap support to S390 kvm.")
Cc: <stable@vger.kernel.org> # 3.16+

Signed-off-by: default avatarJanosch Frank <frankja@linux.vnet.ibm.com>
Reported-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent a8c39dd7

arch/s390/kvm/kvm-s390.c

+3 −0
Original line number Diff line number Diff line
@@ -442,6 +442,9 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, 
	struct kvm_memory_slot *memslot;

	int is_dirty = 0;



	if (kvm_is_ucontrol(kvm))

		return -EINVAL;



	mutex_lock(&kvm->slots_lock);



	r = -EINVAL;