Re: [Qemu-devel] vhost-user breaks after 96a3d98.

[Jason Wang]

On 2017年01月03日 11:09, Jason Wang wrote:
> On 2016年12月30日 20:41, Flavio Leitner wrote:
> > Hi,
> >
> > While I was testing vhost-user using OVS 2.5 and DPDK 2.2.0 in the
> > host and testpmd dpdk 2.2.0 in the guest, I found that the commit
> > below breaks the environment and no packets gets into the guest.
> >
> > dpdk port --> OVS --> vhost-user --> guest --> testpmd
> >                           ^--- drops here         ^--- no packets here.
> >
> > commit 96a3d98d2cdbd897ff5ab33427aa4cfb94077665
> > Author: Jason Wang <address@hidden>
> > Date:   Mon Aug 1 16:07:58 2016 +0800
> >
> >      vhost: don't set vring call if no vector
> >           We used to set vring call fd unconditionally even if guest 
> > driver does
> >      not use MSIX for this vritqueue at all. This will cause lots of
> >      unnecessary userspace access and other checks for drivers does 
> > not use
> >      interrupt at all (e.g virtio-net pmd). So check and clean vring 
> > call
> >      fd if guest does not use any vector for this virtqueue at
> >      all.
> > [...]
> >
> > Thanks,
>
> Hi Flavio:
>
> Thanks for reporting this issue, could this be a bug of vhost-user? (I 
> believe virito-net pmd does not use interrupt for rx/tx at all)
>
> Anyway, will try to reproduce it.

Could not reproduce this issue on similar setups (the only difference is 
I don't create dpdk port) with dpdk 16.11 and ovs.git HEAD. Suspect an 
issue dpdk. Will try OVS 2.5 + DPDK 2.2.0.

Thanks