[PATCH v5 7/8] vhost: vDPA blk device gets ready when the first queue is ready

[Xia, Chenbo]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Monday, October 17, 2022 4:37 PM
> To: Xia, Chenbo <chenbo.xia at intel.com>; 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>
> Subject: Re: [PATCH v5 7/8] vhost: vDPA blk device gets ready when the
> first queue is ready
> 
> 
> 
> On 10/17/22 09:54, Xia, Chenbo wrote:
> >> -----Original Message-----
> >> From: Pei, Andy <andy.pei at intel.com>
> >> Sent: Monday, October 17, 2022 3:14 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
> >> Subject: [PATCH v5 7/8] vhost: vDPA blk device gets ready when the
> first
> >> queue is ready
> >>
> >> When boot from virtio blk device, seabios in QEMU only enables one
> queue.
> >> To work in this scenario, vDPA BLK device back-end configure device
> >> when any queue is ready.
> >>
> >> 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 | 31 +++++++++++++++++++++++++++----
> >>   1 file changed, 27 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> >> index cd65257..f5206dd 100644
> >> --- a/lib/vhost/vhost_user.c
> >> +++ b/lib/vhost/vhost_user.c
> >> @@ -1441,11 +1441,15 @@
> >>   }
> >>
> >>   #define VIRTIO_BUILTIN_NUM_VQS_TO_BE_READY 2u
> >> +#define VIRTIO_BLK_NUM_VQS_TO_BE_READY 1u
> >>
> >>   static int
> >>   virtio_is_ready(struct virtio_net *dev)
> >>   {
> >> +	struct rte_vdpa_device *vdpa_dev;
> >>   	struct vhost_virtqueue *vq;
> >> +	uint32_t vdpa_type;
> >> +	int ret = 0;
> >>   	uint32_t i, nr_vring = dev->nr_vring;
> >>
> >>   	if (dev->flags & VIRTIO_DEV_READY)
> >> @@ -1454,13 +1458,32 @@
> >>   	if (!dev->nr_vring)
> >>   		return 0;
> >>
> >> -	if (dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET) {
> >> -		nr_vring = VIRTIO_BUILTIN_NUM_VQS_TO_BE_READY;
> >> +	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");
> >> +				return -1;
> >> +			}
> >> +		} else {
> >> +			vdpa_type = RTE_VHOST_VDPA_DEVICE_TYPE_NET;
> >> +		}
> >> +	} else {
> >> +		vdpa_type = -1;
> >> +	}
> >
> > Looking at it again, instead of getting the device type again and again,
> > Should we just get and set the type into vdpa_dev when registering a
> vdpa device?
> >
> > What do you think?
> 
> I think this would be preferable.
> 
> If it is to be in struct virtio_net, please take care to place it
> properly not to create new holes. Also, it does not have to be placed in
> hot cachelines.

I am thinking struct rte_vdpa_device. Because if no vdpa device, there will
be no vdpa device type. What do you think?

Thanks,
Chenbo

> 
> Thanks,
> Maxime
> > Thanks,
> > Chenbo
> >
> >>
> >> -		if (dev->nr_vring < nr_vring)
> >> -			return 0;
> >> +	if (vdpa_type == RTE_VHOST_VDPA_DEVICE_TYPE_BLK) {
> >> +		nr_vring = VIRTIO_BLK_NUM_VQS_TO_BE_READY;
> >> +	} else {
> >> +		if (dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET)
> >> +			nr_vring = VIRTIO_BUILTIN_NUM_VQS_TO_BE_READY;
> >>   	}
> >>
> >> +	if (dev->nr_vring < nr_vring)
> >> +		return 0;
> >> +
> >>   	for (i = 0; i < nr_vring; i++) {
> >>   		vq = dev->virtqueue[i];
> >>
> >> --
> >> 1.8.3.1
> >