[PATCH V6 00/19] virtio_ring in order support

From: Jason Wang

Date: Fri Sep 19 2025 - 03:32:07 EST


Hello all:

This sereis tries to implement the VIRTIO_F_IN_ORDER to
virtio_ring. This is done by introducing virtqueue ops so we can
implement separate helpers for different virtqueue layout/features
then the in-order were implemented on top.

Tests shows 2%-19% imporvment with packed virtqueue PPS with KVM guest
vhost-net/testpmd on the host.

Changes since V5:

- rebase on vhost.git linux-next branch
- reorder the total_len to reduce memory comsuming

Changes since V4:

- Fix build error when DEBUG is enabled
- Fix function duplications
- Remove unnecessary new lines

Changes since V3:

- Re-benchmark with the recent vhost-net in order support
- Rename the batched used id and length
- Other minor tweaks

Changes since V2:

- Fix build warning when DEBUG is enabled

Changes since V1:

- use const global array of function pointers to avoid indirect
branches to eliminate retpoline when mitigation is enabled
- fix used length calculation when processing used ids in a batch
- fix sparse warnings


Jason Wang (19):
virtio_ring: rename virtqueue_reinit_xxx to virtqueue_reset_xxx()
virtio_ring: switch to use vring_virtqueue in virtqueue_poll variants
virtio_ring: unify logic of virtqueue_poll() and more_used()
virtio_ring: switch to use vring_virtqueue for virtqueue resize
variants
virtio_ring: switch to use vring_virtqueue for virtqueue_kick_prepare
variants
virtio_ring: switch to use vring_virtqueue for virtqueue_add variants
virtio: switch to use vring_virtqueue for virtqueue_add variants
virtio_ring: switch to use vring_virtqueue for enable_cb_prepare
variants
virtio_ring: use vring_virtqueue for enable_cb_delayed variants
virtio_ring: switch to use vring_virtqueue for disable_cb variants
virtio_ring: switch to use vring_virtqueue for detach_unused_buf
variants
virtio_ring: use u16 for last_used_idx in virtqueue_poll_split()
virtio_ring: introduce virtqueue ops
virtio_ring: determine descriptor flags at one time
virtio_ring: factor out core logic of buffer detaching
virtio_ring: factor out core logic for updating last_used_idx
virtio_ring: factor out split indirect detaching logic
virtio_ring: factor out split detaching logic
virtio_ring: add in order support

drivers/virtio/virtio_ring.c | 889 ++++++++++++++++++++++++++---------
1 file changed, 678 insertions(+), 211 deletions(-)

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2.31.1