I'm trying out VPP native crypto in async mode and ran into a few
issues. I am using 20.09, but the parts below haven't changed in master.
Have I misunderstood the code? I hope someone could comment:
1. The first issue was that processed operations were not being dequeued.
In crypto_sw_scheduler/main.c crypto_sw_scheduler_dequeue_aead()
there is (some parts omitted for clarity):
vec_foreach_index (i, cm->per_thread_data)
{
ptd = cm->per_thread_data + i;
q = ptd->queues[async_op_id];
f = crypto_sw_scheduler_get_pending_frame (q);
if (f)
break;
}
ptd = cm->per_thread_data + vm->thread_index;
if (f)
{
while (n_elts--)
{
crypto_sw_scheduler_convert_aead (vm, ptd, fe, fe - f->elts, bi[0],
sync_op_id, aad_len, tag_len);
bi++;
fe++;
}
process_ops (vm, f, ptd->crypto_ops, &state);
f->state = state;
*enqueue_thread_idx = f->enqueue_thread_index;
}
return crypto_sw_scheduler_get_completed_frame (ptd->queues[async_op_id]);
}
It seems to me that the last line should be:
return crypto_sw_scheduler_get_completed_frame (q);
because we want to dequeue from the queue of the originating thread.
2. I made the above change locally, which led to the second issue:
vnet/crypto/node.c crypto_dequeue_frame() calls
vnet_crypto_async_free_frame() in the context of the worker thread
(not the original enqueueing thread) and tries to free the spent
frame (returned by crypto_sw_scheduler_dequeue_aead() above) back
to the wrong per-thread pool.
It looks to me as if enqueue_thread_idx is ignored by
crypto_dequeue_frame() when instead it should be used somehow to
free the frame back to the correct pool.
3. While looking at all the above, I noticed that all of the loops
involving crypto_sw_scheduler_queue_t * q look like this:
u32 tail = q->tail;
u32 head = q->head;
for (i = tail; i < head; i++)
{
f = q->jobs[i & CRYPTO_SW_SCHEDULER_QUEUE_MASK];
[... do stuff ...]
}
It seems to me that these loops will not work correctly when
head wraps.
Thanks for your comments.
--
G. Paul Ziemba
FreeBSD unix:
6:26AM up 43 days, 35 mins, 16 users, load averages: 1.13, 1.18, 1.16
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