On Tue, Mar 14, 2017 at 01:11:24PM +0100, Maxime Coquelin wrote:
> >+int
> >+rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
> >+ struct rte_vhost_vring *vring)
> >+{
> >+ struct virtio_net *dev;
> >+ struct vhost_virtqueue *vq;
> >+
> >+ dev = get_device(vid);
> >+ if (!dev)
> >+ return -1;
> >+
> >+ if (vring_idx > VHOST_MAX_VRING)
> Shouldn't be ">=" ?
Nice catch!
> >+#define VHOST_MAX_VRING 0x100
> Looking at the code, I'm not clear where this limitation comes from.
> It seems that it can be up to 0x10000, no?
It comes from the vhost-user spec:
--yliu
---
* VHOST_USER_SET_VRING_KICK
Id: 12
Equivalent ioctl: VHOST_SET_VRING_KICK
Master payload: u64
Set the event file descriptor for adding buffers to the vring. It
is passed in the ancillary data.
Bits (0-7) of the payload contain the vring index. Bit 8 is the
invalid FD flag. This flag is set when there is no file descriptor
in the ancillary data. This signals that polling should be used
instead of waiting for a kick.
>
> struct virtio_net {
> ...
> struct vhost_virtqueue *virtqueue[VHOST_MAX_QUEUE_PAIRS * 2];
>
> with:
> #ifdef VIRTIO_NET_F_MQ
> #define VHOST_MAX_QUEUE_PAIRS VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX
> #define VHOST_SUPPORTS_MQ (1ULL << VIRTIO_NET_F_MQ)
> #else
> #define VHOST_MAX_QUEUE_PAIRS 1
> #define VHOST_SUPPORTS_MQ 0
> #endif
>
> and:
> #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000
>
>
> Regards,
> Maxime
