Re: [PATCH v2 0/9] rxq interrupt mode for virtio PMD

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Thu, Dec 29, 2016 at 07:30:34AM +0000, Jianfeng Tan wrote:
> v2:
>   - Add PCI queue/irq config ops.
>   - Move rxq interrupt settings before sending DRIVER OK.
> 
> Historically, virtio PMD can only be binded to igb_uio or
> uio_pci_generic, and not for vfio-pci. Besides, quote from
> http://dpdk.org/doc/guides-16.11/rel_notes/release_2_1.html:
>   "Per queue RX interrupt events are only allowed in VFIO
>    which supports multiple MSI-X vectors."
> 
> As Linux starts to support vfio noiommu mode since 4.8.0, it's
> a good chance to enable rxq interrupt for virtio PMD.

This cover letter (as well as all the commit logs) lacks an _overall_
introducation of how the Rx interrupt works in virtio, say how things
are setup, etc.

	--yliu
> 
> How to test:
> 
> Step 1, prepare a VM image with kernel version >= 4.8.0.
> 
> Step 2, on the host, start a testpmd with a vhost port:
> $ testpmd -c 0x7 -m 1024 --vdev 'eth_vhost0,iface=/tmp/sock0,queues=2' \
> 	--no-pci -- -i --rxq=2 --txq=2 --nb-cores=2
> 
> Step 3, boot the VM:
> $ qemu ... -chardev socket,id=chr1,path=/tmp/sock0 \
> 	-netdev vhost-user,id=net1,chardev=chr1,vhostforce,queues=2 \
> 	-device virtio-net-pci,netdev=net1,mq=on,vectors=5 ...
> 
> Step 4, start l3fwd-power in VM:
> $ l3fwd-power -c 0x3 -n 4 -- -p 1 -P --config="(0,0,1),(0,1,1)" --no-numa
> 
> Step 5, send packets from testpmd on the host:
> $ start tx_first
> 
> Then l3fwd-power outputs:
> L3FWD_POWER: lcore 1 is waked up from rx interrupt on port 0 queue 0
> L3FWD_POWER: lcore 1 is waked up from rx interrupt on port 0 queue 1
> 
> Signed-off-by: Jianfeng Tan <jianfeng.tan@intel.com>
> Jianfeng Tan (9):
>   net/virtio: fix rewriting LSC flag
>   net/virtio: add Rx descriptor check
>   net/virtio: add PCI ops for queue/irq binding
>   net/virtio: add Rx queue intr enable/disable functions
>   net/virtio: setup rxq interrupts
>   net/virtio: unbind intr/eventfd when stop device
>   net/virtio: unmapping queue/irq when close device
>   examples/l3fwd: add parse-ptype option
>   examples/l3fwd-power: fix not stop and close device
> 
>  drivers/net/virtio/virtio_ethdev.c | 149 +++++++++++++++++++++++++++++++++++--
>  drivers/net/virtio/virtio_ethdev.h |   3 +
>  drivers/net/virtio/virtio_pci.c    |  29 ++++++++
>  drivers/net/virtio/virtio_pci.h    |   5 ++
>  drivers/net/virtio/virtio_rxtx.c   |   9 +++
>  drivers/net/virtio/virtqueue.c     |  11 ---
>  drivers/net/virtio/virtqueue.h     |  24 +++++-
>  examples/l3fwd-power/main.c        |  70 ++++++++++++++++-
>  8 files changed, 282 insertions(+), 18 deletions(-)
> 
> -- 
> 2.7.4