Commit 4a34581e authored by Janosch Frank's avatar Janosch Frank Committed by Sasha Levin

KVM: s390: Disable dirty log retrieval for UCONTROL guests

[ Upstream commit e1e8a962 ]

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>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent 6631e70a
......@@ -239,6 +239,9 @@ 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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