KVM: s390: add proper locking for CMMA migration bitmap

Some parts of the cmma migration bitmap is already protected
with the kvm->lock (e.g. the migration start). On the other
hand the read of the cmma bits is not protected against a
concurrent free, neither is the emulation of the ESSA instruction.
Let's extend the locking to all related ioctls by using
the slots lock for
- kvm_s390_vm_start_migration
- kvm_s390_vm_stop_migration
- kvm_s390_set_cmma_bits
- kvm_s390_get_cmma_bits

In addition to that, we use synchronize_srcu before freeing
the migration structure as all users hold kvm->srcu for read.
(e.g. the ESSA handler).

Reported-by: David Hildenbrand <[email protected]>
Signed-off-by: Christian Borntraeger <[email protected]>
Cc: [email protected] # 4.13+
Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
Reviewed-by: Claudio Imbrenda <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>

0 files changed, 0 insertions, 0 deletions