Re: [PATCH v4 3/7] s390: ap: associate a ap_vfio_queue and a matrix mdev

Pierre Morel
2019-03-04T10:19:52Z

On 04/03/2019 03:09, Halil Pasic wrote:
> On Fri, 22 Feb 2019 16:29:56 +0100
> Pierre Morel <pmorel@linux.ibm.com> wrote:
>
>> We need to associate the ap_vfio_queue, which will hold the
>> per queue information for interrupt with a matrix mediated device
>> which hold the configuration and the way to the CRYCB.
> [..]
>> +static int vfio_ap_get_all_domains(struct ap_matrix_mdev *matrix_mdev, int apid)
>> +{
>> + int apqi, apqn;
>> + int ret = 0;
>> + struct vfio_ap_queue *q;
>> + struct list_head q_list;
>> +
>> + INIT_LIST_HEAD(&q_list);
>> +
>> + for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, AP_DOMAINS) {
>> + apqn = AP_MKQID(apid, apqi);
>> + q = vfio_ap_get_queue(apqn, &matrix_dev->free_list);
>> + if (!q) {
>> + ret = -EADDRNOTAVAIL;
>> + goto rewind;
>> + }
>> + if (q->matrix_mdev) {
>> + ret = -EADDRINUSE;
>
> You tried to get the q from matrix_dev->free_list thus modulo races
> q->matrix_mdev should be 0. This change breaks the error codes in a
> sense that it becomes impossible to provoke EADDRINUSE (the proper
> error code for taken by another matrix_mdev).
>

right.
I will change this.

Regards,
Pierre

--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany