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

[Maxime Coquelin]

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.

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
>