On 08.07.2026 09:06, Akihiko Odaki wrote:
I would not pull the peer hashing capability series into 10.0.x just to
backport this.
It is not only a refactoring dependency. Commit 7b6e7e49905d ("virtio-
net: Retrieve peer hashing capability") bumps the virtio-net RSS
subsection from version 1 to 2 and adds supported_hash_types to the
migration stream. It also changes the guest-visible supported_hash_types
value for vhost-vdpa based on backend capability. That is broader than
the RSS validation change and is not migration-stream neutral.
Um, I missed the migration stream changes there, somehow.
Yes, you're definitely right, that's not the way to handle 10.0.x.
For 10.0.x, the safer backport is to add a small
virtio_net_rss_post_load() to the existing version-1 RSS subsection and
keep the subsection version unchanged. The hook only needs to reject
restored indirections_len values that the command path cannot produce:
zero, values above VIRTIO_NET_RSS_MAX_TABLE_LEN, or non-powers of two.
That fixes the crash without pulling in the vhost-vdpa hash capability
behavior change.
And indeed, this was my initial plan, before I played with earlier
commits.
Thank you for the explanation and the suggestion!
/mjt
