Re: [dpdk-dev] [PATCH v4 0/2] net/virtio-user: add packed vq support

[Tiwei Bie <tiwei.bie@intel.com>]

On Fri, Jan 11, 2019 at 10:39:27AM +0100, Jens Freimann wrote:
> Patch 1 fixes a bug in virtio_pq_send_command(). When we wait for
> a descriptor to be marked as used we need to consider that the ring
> might have wrapped and use the previous wrap counter.
> 
> Patch 2 reverts the patch to error out when cq is used with packed vq and
> add support for packed virtqueues in control virtqueue code.
> 
> v3->v4:
>  * it's enough to add to add packed vq feature bit to
>    unsupported_features if packed_vq=0, no need to explicitly add
>    it to device_features (Tiwei) 

Sorry for not making myself clear previously. Just to make
it clear to avoid more confusion: we shouldn't add it to
device_features by ourselves because vhost backend may not
support it. Otherwise, it's possible that the upper layer
in virtio driver will see virtio-user's .get_features()
report this feature while vhost backend doesn't support it.

Thanks for the new version.

> 
> v2->v3:
>  * squash revert patch into patch 2
>  * add new patch 1 to fix a bug in driver code
>  * fix wrap handling code in virtio_user_handle_cq_packed
>  * in v2 I was using wrap counters and indexes from shared virtqueue,
>    fixed this and added wrap counters and used index to virtio_user code
>  * tested wrap around of ring
> 
> v1->v2:
>  * split into two patches
>  * handle ring wrap correctly
>  * add to unsupported_features when packed_vq is 0
> 
> Jens Freimann (2):
>   net/virtio: check head desc with correct wrap counter
>   net/virtio-user: ctrl vq support for packed
> 
>  drivers/net/virtio/virtio_ethdev.c            |  11 +-
>  .../net/virtio/virtio_user/virtio_user_dev.c  | 102 ++++++++++++++++--
>  .../net/virtio/virtio_user/virtio_user_dev.h  |  15 ++-
>  drivers/net/virtio/virtio_user_ethdev.c       |  56 +++++++++-
>  drivers/net/virtio/virtqueue.h                |  10 +-
>  5 files changed, 171 insertions(+), 23 deletions(-)
> 
> -- 
> 2.17.2
>