Control virtqueue is used by networking device for accepting various
commands from the driver. It's a must to support advanced configurations.
Rx filtering event is issues by qemu when device's MAC address changed once and
the previous one has not been queried by external agents.
Shadow VirtQueue (SVQ) already makes possible tracking the state of virtqueues,
effectively intercepting them so qemu can track what regions of memory are
dirty because device action and needs migration. However, this does not solve
networking device state seen by the driver because CVQ messages, like changes
on MAC addresses from the driver.
This series uses SVQ infrastructure to intercept networking control messages
used by the device. This way, qemu is able to update VirtIONet device model and
react to them. In particular, this series enables rx filter change
notification.
This is a prerequisite to achieve net vdpa device with CVQ live migration.
It's a stripped down version of [1], with error paths checked and no migration
enabled.
First ten patches reorder and clean code base so its easier to apply later
ones. No functional change should be noticed from these changes.
Patches from 11 to 15 enable SVQ API to make other parts of qemu to interact
with it. In particular, they will be used by vhost-vdpa net to handle CVQ
messages.
Patches 16 to 18 enable the update of the virtio-net device model for each
CVQ message acknowledged by the device.
Last patches enable x-svq parameter, forbidding device migration since it is
not restored in the destination's vdpa device yet. This will be added in later
series, using this work.
They could conflict trivially with series [2].
Comments are welcome.
v6:
- Add vhost-vdpa-stub.c in case qemu is compiled with no virtio-net support
v5:
- Add a volatile access modifier to force compiler to emit the read instruction
- Fix use of undefined variable
v4:
- Add a timeout to vhost_svq_poll to not hold BQL forever
v3:
- Replace SVQElement with SVQDescState
v2:
- (Comments from series [1]).
- Active poll for CVQ answer instead of relay on async used callback
- Do not offer a new buffer to device but reuse qemu's
- Use vhost_svq_add instead of not needed vhost_svq_inject
- Delete used and detach callbacks, not needed anymore
- Embed members of SVQElement in VirtQueueElement
- Reuse the same buffers for all CVQ commands
[1] https://patchwork.kernel.org/project/qemu-devel/cover/20220706184008.1649478-1-eperezma@redhat.com/
[2] https://lists.nongnu.org/archive/html/qemu-devel/2022-07/msg02984.html
Eugenio Pérez (21):
vhost: move descriptor translation to vhost_svq_vring_write_descs
virtio-net: Expose MAC_TABLE_ENTRIES
virtio-net: Expose ctrl virtqueue logic
vdpa: Avoid compiler to squash reads to used idx
vhost: Reorder vhost_svq_kick
vhost: Move vhost_svq_kick call to vhost_svq_add
vhost: Check for queue full at vhost_svq_add
vhost: Decouple vhost_svq_add from VirtQueueElement
vhost: Add SVQDescState
vhost: Track number of descs in SVQDescState
vhost: add vhost_svq_push_elem
vhost: Expose vhost_svq_add
vhost: add vhost_svq_poll
vhost: Add svq avail_handler callback
vdpa: Export vhost_vdpa_dma_map and unmap calls
vhost-net-vdpa: add stubs for when no virtio-net device is present
vdpa: manual forward CVQ buffers
vdpa: Buffer CVQ support on shadow virtqueue
vdpa: Extract get features part from vhost_vdpa_get_max_queue_pairs
vdpa: Add device migration blocker
vdpa: Add x-svq to NetdevVhostVDPAOptions
qapi/net.json | 9 +-
hw/virtio/vhost-shadow-virtqueue.h | 52 ++++-
include/hw/virtio/vhost-vdpa.h | 8 +
include/hw/virtio/virtio-net.h | 7 +
hw/net/virtio-net.c | 85 ++++---
hw/virtio/vhost-shadow-virtqueue.c | 210 ++++++++++++-----
hw/virtio/vhost-vdpa.c | 26 ++-
net/vhost-vdpa-stub.c | 21 ++
net/vhost-vdpa.c | 357 +++++++++++++++++++++++++++--
net/meson.build | 3 +-
10 files changed, 658 insertions(+), 120 deletions(-)
create mode 100644 net/vhost-vdpa-stub.c
--
2.31.1