Re: [PATCH 2/3] virtio: Define bit numbers for device independent features

From: Eli Cohen <elic@nvidia.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Hemminger, Stephen" <stephen@networkplumber.org>,
	netdev <netdev@vger.kernel.org>,
	Si-Wei Liu <si-wei.liu@oracle.com>,
	Jianbo Liu <jianbol@nvidia.com>
Subject: Re: [PATCH 2/3] virtio: Define bit numbers for device independent features
Date: Thu, 10 Feb 2022 10:30:50 +0200	[thread overview]
Message-ID: <20220210083050.GA224722@mtl-vdi-166.wap.labs.mlnx> (raw)
In-Reply-To: <CACGkMEvF7opCo35QLz4p3u7=T1+H-p=isFm4+yh4uNzKiAxr1A@mail.gmail.com>

On Thu, Feb 10, 2022 at 03:54:57PM +0800, Jason Wang wrote:
> On Mon, Feb 7, 2022 at 8:56 PM Eli Cohen <elic@nvidia.com> wrote:
> >
> > Define bit fields for device independent feature bits. We need them in a
> > follow up patch.
> >
> > Also, define macros for start and end of these feature bits.
> >
> > Reviewed-by: Jianbo Liu <jianbol@nvidia.com>
> > Signed-off-by: Eli Cohen <elic@nvidia.com>
> > ---
> >  include/uapi/linux/virtio_config.h | 16 ++++++++--------
> >  1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
> > index 3bf6c8bf8477..6d92cc31a8d3 100644
> > --- a/include/uapi/linux/virtio_config.h
> > +++ b/include/uapi/linux/virtio_config.h
> > @@ -45,14 +45,14 @@
> >  /* We've given up on this device. */
> >  #define VIRTIO_CONFIG_S_FAILED         0x80
> >
> > -/*
> > - * Virtio feature bits VIRTIO_TRANSPORT_F_START through
> > - * VIRTIO_TRANSPORT_F_END are reserved for the transport
> > - * being used (e.g. virtio_ring, virtio_pci etc.), the
> > - * rest are per-device feature bits.
> > - */
> > -#define VIRTIO_TRANSPORT_F_START       28
> > -#define VIRTIO_TRANSPORT_F_END         38
> > +/* Device independent features per virtio spec 1.1 range from 28 to 38 */
> > +#define VIRTIO_DEV_INDEPENDENT_F_START 28
> > +#define VIRTIO_DEV_INDEPENDENT_F_END   38
> 
> Haven't gone through patch 3 but I think it's probably better not
> touch uapi stuff. Or we can define those macros in other place?
> 

I can put it in vdpa.c

> > +
> > +#define VIRTIO_F_RING_INDIRECT_DESC 28
> > +#define VIRTIO_F_RING_EVENT_IDX 29
> > +#define VIRTIO_F_IN_ORDER 35
> > +#define VIRTIO_F_NOTIFICATION_DATA 38
> 
> This part belongs to the virtio_ring.h any reason not pull that file
> instead of squashing those into virtio_config.h?
> 

Not sure what you mean here. I can't find virtio_ring.h in my tree.

> Thanks
> 
> >
> >  #ifndef VIRTIO_CONFIG_NO_LEGACY
> >  /* Do we get callbacks when the ring is completely used, even if we've
> > --
> > 2.34.1
> >
> 