Re: [virtio-comment] VIRTIO_NET_F_MRG_RXBUF number of descriptors

[Stefan Hajnoczi <stefanha@redhat.com>]

On Tue, Jul 09, 2019 at 06:35:13AM +0000, Savir, Gil wrote:
> Hi,
> 
> v1.1 states at Section 5.1.6.3.2 (Device Requirements: Setting Up Receive Buffers): 
> 	"The device MUST use only a single descriptor if VIRTIO_NET_F_MRG_RXBUF was not negotiated." 
> That's a mistake, since the device can, and should be able to use multiple descriptors, pertaining to the same descriptors chain.
> 
> Therefore I suggest to change it to: 
> 	" The device MUST use only a single descriptor-chain if VIRTIO_NET_F_MRG_RXBUF was not negotiated."
> 
> BTW, as result of this wrongly formulated sentence, I came across many people (including my-past-self) that confuse MRG_RXBUF feature with descriptors-chain support.
> Fixing it will help avoiding this confusion. 

Hi Gil,
Perhaps the clearest way of phrasing this is:

  "The device MUST use only a single used buffer if
  VIRTIO_NET_F_MRG_RXBUF was not negotiated."

The "used buffer" terminology comes and is consistent with 2.5
Virtqueues.

Do you agree and would you like to send a patch?

Stefan

Attachment: signature.asc
Description: PGP signature