[dpdk-dev] OVDK userspace vhost : Issue with VIRTIO_RING_F_INDIRECT_DESC capability

[Gray, Mark D]

Cross posting to OVDK list.

On a side point, Have you looked at the DPDK enabled build in upstream OVS?

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of sai kiran
> Sent: Wednesday, July 1, 2015 1:02 PM
> To: dev at dpdk.org
> Subject: [dpdk-dev] OVDK userspace vhost : Issue with
> VIRTIO_RING_F_INDIRECT_DESC capability
> 
> Hi,
> 
> I am using OVDK userspace-vhost interfaces for VM-to-external
> communication and facing an issue with them.
> 
> I am using the topology mentioned in
> https://github.com/01org/dpdk-
> ovs/blob/development/docs/04_Sample_Configurations/02_Userspace-
> vHost.md
> But the Guest is a Freebsd VM and our own custom userspace virtio drivers.
> Guest does not have DPDK.
> 
> 
>    1. I could start OVDK application and vswitchd, and provision a FreeBSD
>    Guest VM with two userspace-vhost interfaces.
>    2. These two userspace-vhost interfaces do not have
> VIRTIO_RING_F_INDIRECT_DESC
>    capability negotiated from backend OVDK-Qemu
>    3. Inside the freebsd VM, i have my own userspace drivers running, which
>    make use of indirect descriptors of virtio.
>    4. *Question 1* : By default, without INDIRECT descriptor capability, my
>    drivers fail to run.    Is there any way to increase ring size of
>    virtio?     This can help us  avoid using indirect descriptors because of
>    more space in the ring
>    5. *Question 2*: When I try to set the capability from backend QEMU,
>    guest drivers do not see any packets reaching the guest.     Is there
>    any way to resolve this ??
> 
> Any help/suggestion would be of great help.
> 
> *Thanks & Regards,*
> *Saikiran V*