[PATCH v2 7/8] vhost: configure device when any queue is ready for BLK device

[Pei, Andy]

HI Chenbo, 

Thanks for your reply, my reply is inline.

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia at intel.com>
> Sent: Wednesday, September 14, 2022 10:51 AM
> To: Pei, Andy <andy.pei at intel.com>; dev at dpdk.org
> Cc: Xu, Rosen <rosen.xu at intel.com>; Huang, Wei <wei.huang at intel.com>; Cao,
> Gang <gang.cao at intel.com>; maxime.coquelin at redhat.com
> Subject: RE: [PATCH v2 7/8] vhost: configure device when any queue is ready for
> BLK device
> 
> > -----Original Message-----
> > From: Pei, Andy <andy.pei at intel.com>
> > Sent: Thursday, September 8, 2022 1:54 PM
> > To: dev at dpdk.org
> > Cc: Xia, Chenbo <chenbo.xia at intel.com>; Xu, Rosen
> > <rosen.xu at intel.com>; Huang, Wei <wei.huang at intel.com>; Cao, Gang
> > <gang.cao at intel.com>; maxime.coquelin at redhat.com; Huang Wei
> > <wei_huang at intel.com>
> > Subject: [PATCH v2 7/8] vhost: configure device when any queue is
> > ready for BLK device
> >
> > When boot from virtio blk device, seabois in QEMU only enables one queue.
> > To work in this scenario, vDPA BLK device back-end conf_dev when any
> > queue is ready.
> 
> So this is the case only for vdpa blk, for SW vhost-blk, all queues need to be
> ready?
> 
The case I mention is that the OS image is in the vdpa device.
In this case, QEMU bios (seabios) will take charge. There is a virtio driver in seabios.
This driver only use one queue.
So in this case vdpa driver need to conf_dev when one queue is ready.

for SW vhost-blk, I am not sure you mean OS image is in your back-end vhost-blk.
I have not test that case.

> >
> > Signed-off-by: Andy Pei <andy.pei at intel.com>
> > Signed-off-by: Huang Wei <wei_huang at intel.com>
> > ---
> >  lib/vhost/vhost_user.c | 56
> > +++++++++++++++++++++++++++++++++++++++------
> > -----
> >  1 file changed, 44 insertions(+), 12 deletions(-)
> >
> > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c index
> > 4ad28ba..b65fba3 100644
> > --- a/lib/vhost/vhost_user.c
> > +++ b/lib/vhost/vhost_user.c
> > @@ -1451,6 +1451,25 @@
> >  #define VIRTIO_BUILTIN_NUM_VQS_TO_BE_READY 2u
> >
> >  static int
> > +virtio_has_queue_ready(struct virtio_net *dev) {
> > +	struct vhost_virtqueue *vq;
> > +	uint32_t i, nr_vring = dev->nr_vring;
> > +
> > +	if (!dev->nr_vring)
> > +		return 0;
> > +
> > +	for (i = 0; i < nr_vring; i++) {
> > +		vq = dev->virtqueue[i];
> > +
> > +		if (vq_is_ready(dev, vq))
> > +			return 1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int
> >  virtio_is_ready(struct virtio_net *dev)  {
> >  	struct vhost_virtqueue *vq;
> > @@ -3167,9 +3186,33 @@ static int is_vring_iotlb(struct virtio_net *dev,
> >  	if (unlock_required)
> >  		vhost_user_unlock_all_queue_pairs(dev);
> >
> > -	if (ret != 0 || !virtio_is_ready(dev))
> > +	if (ret != 0)
> >  		goto out;
> >
> > +	vdpa_dev = dev->vdpa_dev;
> > +	if (vdpa_dev) {
> > +		if (vdpa_dev->ops->get_dev_type) {
> > +			ret = vdpa_dev->ops->get_dev_type(vdpa_dev,
> &vdpa_type);
> > +			if (ret) {
> > +				VHOST_LOG_CONFIG(dev->ifname, ERR,
> > +					"failed to get vdpa dev type.\n");
> > +				ret = -1;
> > +				goto out;
> > +			}
> > +		} else {
> > +			vdpa_type = RTE_VHOST_VDPA_DEVICE_TYPE_NET;
> > +		}
> > +	}
> > +
> > +	if (!virtio_is_ready(dev)) {
> > +		if (vdpa_type == RTE_VHOST_VDPA_DEVICE_TYPE_BLK) {
> > +			if (!virtio_has_queue_ready(dev))
> > +				goto out;
> > +		} else {
> > +			goto out;
> > +		}
> > +	}
> > +
> 
> I feel like if possible, above logic should all be in virtio_is_ready.
> 
Maybe I can introduce something like VIRTIO_DEV_BUILTIN_VIRTIO_NET,
What do you think?

> Thanks,
> Chenbo
> 
> >  	/*
> >  	 * Virtio is now ready. If not done already, it is time
> >  	 * to notify the application it can process the rings and @@
> > -3181,20 +3224,9 @@ static int is_vring_iotlb(struct virtio_net *dev,
> >  			dev->flags |= VIRTIO_DEV_RUNNING;
> >  	}
> >
> > -	vdpa_dev = dev->vdpa_dev;
> >  	if (!vdpa_dev)
> >  		goto out;
> >
> > -	if (vdpa_dev->ops->get_dev_type) {
> > -		ret = vdpa_dev->ops->get_dev_type(vdpa_dev, &vdpa_type);
> > -		if (ret) {
> > -			VHOST_LOG_CONFIG(dev->ifname, ERR, "failed to get
> vdpa
> > dev type.\n");
> > -			ret = -1;
> > -			goto out;
> > -		}
> > -	} else {
> > -		vdpa_type = RTE_VHOST_VDPA_DEVICE_TYPE_NET;
> > -	}
> >  	if (vdpa_type == RTE_VHOST_VDPA_DEVICE_TYPE_BLK
> >  		&& request != VHOST_USER_SET_VRING_CALL)
> >  		goto out;
> > --
> > 1.8.3.1