Virtualization - Jun 2022 - [PATCH 5/6] vDPA: answer num of queue pairs = 1 to userspace when VIRTIO_NET_F_MQ == 0

On Mon, Jun 6, 2022 at 4:22 PM Zhu, Lingshan <lingshan.zhu at intel.com>
wrote:
>
>
>
> On 6/2/2022 3:38 PM, Jason Wang wrote:
> > On Thu, Jun 2, 2022 at 10:48 AM Zhu Lingshan <lingshan.zhu at
intel.com> wrote:
> >> If VIRTIO_NET_F_MQ == 0, the virtio device should have one queue
pair,
> >> so when userspace querying queue pair numbers, it should return
mq=1
> >> than zero
> > Spec said:
> >
> > "max_virtqueue_pairs only exists if VIRTIO_NET_F_MQ is set"
> >
> > So we are probably fine.
> I thinks it is asking how many queue
> pairs(VDPA_ATTR_DEV_NET_CFG_MAX_VQP), so answering 0 may not be correct.
>
> Thanks,
> Zhu Lingshan
Please add the result of the userspace vdpa tool before and after this
patch in the changlog in next version.

Thanks
> >
> > Thanks
> >
> >> Signed-off-by: Zhu Lingshan <lingshan.zhu at intel.com>
> >> ---
> >>   drivers/vdpa/vdpa.c | 5 +++--
> >>   1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> >> index 030d96bdeed2..50a11ece603e 100644
> >> --- a/drivers/vdpa/vdpa.c
> >> +++ b/drivers/vdpa/vdpa.c
> >> @@ -818,9 +818,10 @@ static int vdpa_dev_net_mq_config_fill(struct
vdpa_device *vdev,
> >>          u16 val_u16;
> >>
> >>          if ((features & BIT_ULL(VIRTIO_NET_F_MQ)) == 0)
> >> -               return 0;
> >> +               val_u16 = 1;
> >> +       else
> >> +               val_u16 = le16_to_cpu((__force
__le16)config->max_virtqueue_pairs);
> >>
> >> -       val_u16 = le16_to_cpu(config->max_virtqueue_pairs);
> >>          return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP,
val_u16);
> >>   }
> >>
> >> --
> >> 2.31.1
> >>
>