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Commit 4385a234 authored by Janosch Frank's avatar Janosch Frank Committed by Greg Kroah-Hartman
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KVM: s390: Disable dirty log retrieval for UCONTROL guests 



commit e1e8a9624f7ba8ead4f056ff558ed070e86fa747 upstream.

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.")
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>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f9848214

arch/s390/kvm/kvm-s390.c

+3 −0
Original line number Diff line number Diff line
@@ -207,6 +207,9 @@ 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;