From: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx>
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: 15f36eb ("KVM: s390: Add proper dirty bitmap support to S390 kvm.")
Cc: <stable@xxxxxxxxxxxxxxx> # 3.16+
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxxxxxxx>
Reported-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/kvm/kvm-s390.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index dabd3b15..502de74 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -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;
--
2.7.4
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