Commit e1e8a962 authored Feb 02, 2017 by Janosch Frank Committed by Christian Borntraeger Feb 06, 2017

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: Janosch Frank <frankja@linux.vnet.ibm.com>
Reported-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian 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;

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