Module test_helpers 

Shared test helpers for writing integration tests that drive virtio devices through descriptor rings.

These helpers manipulate split virtqueue descriptor tables, available rings, and used rings in guest memory — the same operations a guest driver would perform.

Functions

init_avail_ring

Initialize an avail ring (flags=0, idx=0).

init_used_ring

Initialize a used ring (flags=0, idx=0).

make_available

Make a descriptor index available in the avail ring and bump the index.

read_used

Read the next used ring entry, returning (desc_id, bytes_written) or None if no new entries are available.

read_used_entry

Read a used ring entry (id, len) at the given ring index.

read_used_idx

Read the used ring index.

wait_for_used

Wait for the next used ring entry, polling with a timeout.

write_descriptor

Write a split virtio descriptor at the given descriptor table base.