On 64bit arches, struct u64_stats_sync is empty and provides no help
against load/store tearing. Convert to u64_stats_t to ensure atomic
operations.

Signed-off-by: David Yang <mmyangfl@gmail.com>
Link: https://patch.msgid.link/20260123211101.2929547-1-mmyangfl@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

For now only tx/rx packets/bytes are reported. This is not compliant
with the PSP Architecture Specification.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20251106002608.1578518-6-daniel.zahka@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Provide a PSP implementation for netdevsim.

Use psp_dev_encapsulate() and psp_dev_rcv() to do actual encapsulation
and decapsulation on skbs, but perform no encryption or decryption. In
order to make encryption with a bad key result in a drop on the peer's
rx side, we stash our psd's generation number in the first byte of each
key before handing to the peer.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Co-developed-by: Daniel Zahka <daniel.zahka@gmail.com>
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20250927225420.1443468-2-kuba@kernel.org
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>