The mdev remove callback for the vfio_ap device driver bails out with -EBUSY if the mdev is in use by a KVM guest. The intended purpose was to prevent the mdev from being removed while in use; however, returning a non-zero rc does not prevent removal of the mdev. Consequently, the memory for the resources allocated when the mdev was created are leaked. To fix this issue: * The remove callback will not terminate with -EBUSY when the mdev is in use by a KVM guest. * The memory for the resources allocated when the mdev was created will be freed. * Since the struct ap_matrix_mdev now gets freed while the guest is is still running, we need to ensure that the pointer to the function that handles interception of the PQAP instruction executed on the guest is not accessed while it is being set to NULL. To prevent this, a r/w lock is introduced that protects the function pointer. Tony Krowiak (2): s390/vfio-ap: clean up mdev resources when remove callback invoked s390/vfio-ap: r/w lock for PQAP interception handler function pointer arch/s390/include/asm/kvm_host.h | 6 +++--- arch/s390/kvm/kvm-s390.c | 1 + arch/s390/kvm/priv.c | 6 +++--- drivers/s390/crypto/vfio_ap_ops.c | 31 ++++++++++++++------------- drivers/s390/crypto/vfio_ap_private.h | 2 +- 5 files changed, 24 insertions(+), 22 deletions(-) -- 2.30.2
