quoted

The problem is that with new approach you proposed there is no simple way
for PMD to
fulfil that requirement.
In current version of DPDK:
- PMD reports size of private data, note that it reports extra space needed
   to align its data properly inside provided buffer.
- Then it ss up to higher layer to allocate mempool with elements big enough
to hold
   PMD private data.
- At session init that mempool is passed to PMD sym_session_confgure() and
it is
 PMD responsibility to allocate buffer (from given mempool) for its private
data
  align it properly, and update sess->sess_data[].data.
With this patch:
 -  PMD still reports size of private data, but now it is cryptodev layer who
allocates
     memory for PMD private data and updates sess->sess_data[].data.

So PMD simply has no way to allocate/align its private data in a way it likes
to.
Of course it can simply do alignment on the fly for each operation, something
like:

void *p = get_sym_session_private_data(sess, dev->driver_id);
sess_priv = RTE_PTR_ALIGN_FLOOR(p, PMD_SES_ALIGN);

But it is way too ugly and error-prone.

Another potential problem with that approach (when cryptodev allocates
memory for
PMD private session data and updates sess->sess_data[].data for it) - it could
happen
that private data for different PMDs can endup on the same cache-line.
If we'll ever have a case with simultaneous session processing by multiple-
devices
it can cause all sorts of performance problems.

To resolve above 2 issues(performance and pointer CEIL in PMD), can you check
If following diff in library would work?
----------------------------------------------------------------------------------------------------

diff --git a/lib/cryptodev/rte_cryptodev.c b/lib/cryptodev/rte_cryptodev.c
index 9d5e08bba2..7beb5339ea 100644
--- a/lib/cryptodev/rte_cryptodev.c
+++ b/lib/cryptodev/rte_cryptodev.c

@@ -1731,12 +1731,13 @@ rte_cryptodev_sym_session_init(uint8_t dev_id,
        RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->sym_session_configure, -ENOTSUP);

        if (sess->sess_data[index].refcnt == 0) {
-               sess->sess_data[index].data = (void *)((uint8_t *)sess +
+               sess->sess_data[index].data = RTE_PTR_ALIGN_CEIL(
+                               (void *)((uint8_t *)sess +
                                rte_cryptodev_sym_get_header_session_size() +
-                               (index * sess->priv_sz));
-               sess_iova = rte_mempool_virt2iova(sess) +
+                               (index * sess->priv_sz)), RTE_CACHE_LINE_SIZE);
+               sess_iova = RTE_ALIGN_CEIL(rte_mempool_virt2iova(sess) +
                                rte_cryptodev_sym_get_header_session_size() +
-                               (index * sess->priv_sz);
+                               (index * sess->priv_sz), RTE_CACHE_LINE_SIZE);
                ret = dev->dev_ops->sym_session_configure(dev, xforms,
                                sess->sess_data[index].data, sess_iova);
                if (ret < 0) {

@@ -1805,7 +1806,7 @@ get_max_sym_sess_priv_sz(void)
                if (sz > max_sz)
                        max_sz = sz;
        }
-       return max_sz;
+       return RTE_ALIGN_CEIL(max_sz,RTE_CACHE_LINE_SIZE);
 }

 struct rte_mempool *