Re: [PATCH] vhost: fix wait for valid descriptor

From: Thomas Monjalon <thomas@monjalon.net>
To: maxime.coquelin@redhat.com, tiwei.bie@intel.com
Cc: dev@dpdk.org, "Kulasek, TomaszX" <tomaszx.kulasek@intel.com>,
	"yliu@fridaylinux.org" <yliu@fridaylinux.org>,
	"Liu, Changpeng" <changpeng.liu@intel.com>
Subject: Re: [PATCH] vhost: fix wait for valid descriptor
Date: Thu, 26 Jul 2018 17:48:04 +0200	[thread overview]
Message-ID: <30052203.PRpXP6jO5E@xps> (raw)
In-Reply-To: <ED26CBA2FAD1BF48A8719AEF02201E3651439D5C@SHSMSX103.ccr.corp.intel.com>

What is the status of this patch?

11/02/2018 05:21, Tan, Jianfeng:
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Tomasz Kulasek
> > Sent: Saturday, February 10, 2018 1:35 AM
> > To: yliu@fridaylinux.org
> > Cc: dev@dpdk.org; yuanhan.liu@linux.intel.com; stable@dpdk.org; Liu,
> > Changpeng
> > Subject: [dpdk-dev] [PATCH] vhost: fix wait for valid descriptor
> > 
> > For each virt queue's kickfd and callfd, there are 2 invalid
> > status: VIRTIO_UNINITIALIZED_EVENTFD and VIRTIO_INVALID_EVENTFD.
> > Don't set the virt queue to ready status until got the valid
> > descriptor.
> 
> Cannot remember why we introduce two invalid status.
> 
> If we treat "VIRTIO_INVALID_EVENTFD" as an indicator to judge if device is ready, then defining one status (invalid) is enough.
> 
> Thanks,
> Jianfeng
> 
> > 
> > This is safe for polling mode drivers in Guest OS, the backend
> > vhost process will not post notification to interrupt vector for
> > PMD mode in guest, but the interrupt vector still valid.
> > 
> > Fixes: e049ca6d10e0 ("vhost-user: prepare multiple queue setup")
> > Cc: yuanhan.liu@linux.intel.com
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
> > Signed-off-by: Tomasz Kulasek <tomaszx.kulasek@intel.com>
> > ---
> >  lib/librte_vhost/vhost_user.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> > index 65ee33919..4508f697b 100644
> > --- a/lib/librte_vhost/vhost_user.c
> > +++ b/lib/librte_vhost/vhost_user.c
> > @@ -766,7 +766,9 @@ vq_is_ready(struct vhost_virtqueue *vq)
> >  {
> >  	return vq && vq->desc && vq->avail && vq->used &&
> >  	       vq->kickfd != VIRTIO_UNINITIALIZED_EVENTFD &&
> > -	       vq->callfd != VIRTIO_UNINITIALIZED_EVENTFD;
> > +	       vq->callfd != VIRTIO_UNINITIALIZED_EVENTFD &&
> > +	       vq->kickfd != VIRTIO_INVALID_EVENTFD &&
> > +	       vq->callfd != VIRTIO_INVALID_EVENTFD;
> >  }
> > 
> >  static int
> > --
> > 2.14.1
> 