Re: [dpdk-dev] [dpdk-stable] [PATCH v5] net/virtio-user: fix packed ring server mode

["Ding, Xuan" <xuan.ding@intel.com>]

Hi Ferruh,

> -----Original Message-----
> From: Yigit, Ferruh <ferruh.yigit@intel.com>
> Sent: Wednesday, January 15, 2020 11:41 PM
> To: Maxime Coquelin <maxime.coquelin@redhat.com>; Ding, Xuan
> <xuan.ding@intel.com>; Bie, Tiwei <tiwei.bie@intel.com>; Wang, Zhihong
> <zhihong.wang@intel.com>; Liu, Yong <yong.liu@intel.com>; Ye, Xiaolong
> <xiaolong.ye@intel.com>
> Cc: dev@dpdk.org; stable@dpdk.org
> Subject: Re: [dpdk-stable] [PATCH v5] net/virtio-user: fix packed ring server
> mode
> 
> On 1/15/2020 11:16 AM, Maxime Coquelin wrote:
> >
> >
> > On 1/15/20 7:13 AM, Xuan Ding wrote:
> >> This patch fixes the situation where data path does not work properly
> >> when vhost reconnects to virtio in server mode with packed ring.
> >>
> >> Currently, virtio and vhost share memory of vring. For split ring,
> >> vhost can read the status of descriptors directly from the available
> >> ring and the used ring during reconnection. Therefore, the data path can
> continue.
> >>
> >> But for packed ring, when reconnecting to virtio, vhost cannot get
> >> the status of descriptors via the descriptor ring. By resetting Tx
> >> and Rx queues, the data path can restart from the beginning.
> >>
> >> Fixes: 4c3f5822eb214 ("net/virtio: add packed virtqueue defines")
> >> Cc: stable@dpdk.org
> >>
> >> Signed-off-by: Xuan Ding <xuan.ding@intel.com>
> >> ---
> >>
> >> v5:
> >> * Fixed two spelling mistakes in the commit log.
> >> * Added notice message when resetting vring.
> >>
> >> v4:
> >> * Moved change log below '---' marker.
> >>
> >> v3:
> >> * Removed an extra asterisk from a comment.
> >> * Renamed device reset function and moved it to virtio_user_ethdev.c.
> >>
> >> v2:
> >> * Renamed queue reset functions and moved them to virtqueue.c.
> >> ---
> >>  drivers/net/virtio/virtio_ethdev.c      |  4 +-
> >>  drivers/net/virtio/virtio_user_ethdev.c | 42 +++++++++++++++
> >>  drivers/net/virtio/virtqueue.c          | 71 +++++++++++++++++++++++++
> >>  drivers/net/virtio/virtqueue.h          |  4 ++
> >>  4 files changed, 119 insertions(+), 2 deletions(-)
> >
> > Applied to dpdk-next-virtio/master
> >
> 
> This was causing build error [1] on cross compilation [2], I am fixing it while
> merging [3], please double check in next-net.
> 
> [1]
> .../drivers/net/virtio/virtio_user_ethdev.c:44:2: error: implicit declaration of
> function ‘rte_delay_ms’; did you mean ‘rte_realloc’?
> [-Werror=implicit-function-declaration]
> 
>   rte_delay_ms(1);
> 
> 
> [2]
> CROSS=/opt/aarch64/bin/aarch64-buildroot-linux-gnu- make -j64
> 
> 
> [3]
> diff --git a/drivers/net/virtio/virtio_user_ethdev.c
> b/drivers/net/virtio/virtio_user_ethdev.c
> index 9c9d3407f..f3b35d1bd 100644
> --- a/drivers/net/virtio/virtio_user_ethdev.c
> +++ b/drivers/net/virtio/virtio_user_ethdev.c
> @@ -13,6 +13,7 @@
>  #include <rte_ethdev_vdev.h>
>  #include <rte_bus_vdev.h>
>  #include <rte_alarm.h>
> +#include <rte_cycles.h>
> 
>  #include "virtio_ethdev.h"
>  #include "virtio_logs.h"


After my check, the current call path to rte_cycles.h on the x86 platform is  virtio_user_ethdev.c -> virtqueue.h ->  rte_mempool.h -> rte_spinlock.h -> rte_cycles.h. I find that only rte_spinlock.h on the x86 platform includes the rte_cycles.h, while this file is not included on other platforms, so your fix is right. I also test the new patch(add #include <rte_cycles.h>) on my local, it works fine.

Thank you very much.

Regards,
Xuan