RE: [PATCH 1/2] vdpa: Allow to configure max data virtqueues

[Parav Pandit via Virtualization]

> From: Eli Cohen <e...@nvidia.com>
> Sent: Wednesday, December 1, 2021 3:33 PM
> 
> On Tue, Nov 30, 2021 at 05:24:03PM -0800, Si-Wei Liu wrote:
> >
> >
> > On 11/30/2021 1:48 AM, Eli Cohen wrote:
> > > Allow to configure the max virtqueues for a device.
> > >
> > > Signed-off-by: Eli Cohen <e...@nvidia.com>
> > > ---
> > >   drivers/vdpa/vdpa.c  | 16 +++++++++++++++-
> > >   include/linux/vdpa.h |  1 +
> > >   2 files changed, 16 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index
> > > 7332a74a4b00..e185ec2ee851 100644
> > > --- a/drivers/vdpa/vdpa.c
> > > +++ b/drivers/vdpa/vdpa.c
> > > @@ -480,7 +480,8 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff
> *msg, struct netlink_callback *cb)
> > >   }
> > >   #define VDPA_DEV_NET_ATTRS_MASK ((1 <<
> VDPA_ATTR_DEV_NET_CFG_MACADDR) | \
> > > -                          (1 << VDPA_ATTR_DEV_NET_CFG_MTU))
> > > +                          (1 << VDPA_ATTR_DEV_NET_CFG_MTU) | \
> > > +                          (1 << VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
> > It seems VDPA_ATTR_DEV_MAX_VQS (u32) is what you want (# of data
> > virtqueues instead of # of data virtqueue pairs)? Not sure what's
> > possible use of VDPA_ATTR_DEV_NET_CFG_MAX_VQP, was it to
> dump/display
> > the config space max_virtqueue_pairs value (u16, 1-32768) for
> > virtio-net? Why there's such quasi-duplicate attribute introduced in the 
> > first
> place?
> >
> 
> VDPA_ATTR_DEV_MAX_VQS currently returns vdev->nvqs which equals
> whatever passed to _vdpa_register_device(). The latter depends on the value
> provided by (struct vdpa_dev_set_config).max_virtqueues. 
> 
Max VQs configuration should reuse VDPA_ATTR_DEV_MAX_VQS.
it indicates what is the max vqs a given vdpa device is using. Until now it was 
driver's choice, now its users choice if provided.
So no need for additional attribute.

> Maybe we should add attributes to add aditional virtqueues like control
> virtqueue and their index. They could be returned by
> vdpa_dev_net_config_fill().
Yes. 
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization