On 07/26/2018 09:54 PM, Christian Borntraeger wrote:
@@ -65,6 +66,21 @@ static int vfio_ap_matrix_dev_create(void) { int ret;+ mutex_init(&matrix_dev.lock);+ INIT_LIST_HEAD(&matrix_dev.mdev_list); + + /* Test if PQAP(QCI) instruction is available */ + if (test_facility(12)) { + ret = ap_qci(&matrix_dev.info); + if (ret && (ret != -EOPNOTSUPP)) {
After Connie's curiosity was piqued I gave this another look. If I read the ap_qci() documentation and code correctly, it can return either 0 or -EOPNOTSUPP, but nothing else. So basically this is a dead branch. Either removing the && (ret != -EOPNOTSUPP) and adding some fancy error reporting, or removing the check alltoghether would make more sense than what we have right now. Should we do something? But don't misunderstand me, what we have right now is safe.
+ vfio_ap_mdev_unregister(); + + return ret; + } + }
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