Re: [PATCH 1/3] s390/vfio-ap: clean up mdev resources when remove callback invoked

Christian Borntraeger
2021-06-15T07:44:03Z

On 11.06.21 18:48, Jason Gunthorpe wrote:
> On Wed, Jun 09, 2021 at 06:46:32PM -0400, Tony Krowiak wrote:
>> The mdev remove callback for the vfio_ap device driver bails out with
>> -EBUSY if the mdev is in use by a KVM guest (i.e., the KVM pointer in the
>> struct ap_matrix_mdev is not NULL). The intended purpose was
>> to prevent the mdev from being removed while in use. There are two
>> problems with this scenario:
>>
>> 1. Returning a non-zero return code from the remove callback does not
>> prevent the removal of the mdev.
>>
>> 2. The KVM pointer in the struct ap_matrix_mdev will always be NULL because
>> the remove callback will not get invoked until the mdev fd is closed.
>> When the mdev fd is closed, the mdev release callback is invoked and
>> clears the KVM pointer from the struct ap_matrix_mdev.
>>
>> Let's go ahead and remove the check for KVM in the remove callback and
>> allow the cleanup of mdev resources to proceed.
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>> ---
>> drivers/s390/crypto/vfio_ap_ops.c | 10 ----------
>> 1 file changed, 10 deletions(-)
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason, I guess you want this patch still in 5.13, the other 2 can be 5.14?