Re: [RFC] EAL: legacy memory fixed address translations

[Don Wallwork <donw@xsightlabs.com>]

On 7/27/2022 3:12 PM, Stephen Hemminger wrote:
> On Wed, 27 Jul 2022 13:20:22 -0400
> Don Wallwork <donw@xsightlabs.com> wrote:
>
>>> When drivers need to process a large number of memory blocks,
>>> these are typically packets in the form of mbufs,
>>> which already have IOVA attached, so there is no translation.
>>> Does translation of mbuf VA to PA with the proposed method
>>> show significant improvement over reading mbuf->iova?
>> This proposal does not relate to mbufs.  As you say, there is
>> already an efficient VA to PA mechanism in place for those.
>
> If the only user of this would be your out of tree code,
> then it would never get tested by normal process.
> Therefore it would be regularly broken by other changes.

While we're not yet ready to upstream our drivers, we are actively
working to get our code ready for that.  It is expected that other
devices may be able to take advantage of this capability.  In the
meantime, tests could be added to prevent such breakage.