RE: packed ring layout proposal v3

-----Original Message-----
From: virtualization-bounces@lists.linux-foundation.org
[mailto:virtualization-bounces@lists.linux-foundation.org] On Behalf Of
Michael S. Tsirkin
Sent: Sunday, September 10, 2017 8:06 AM
To: virtio-dev@lists.oasis-open.org
Cc: virtualization@lists.linux-foundation.org
Subject: packed ring layout proposal v3

This is an update from v2 version.

...

When driver descriptors are chained in this way, multiple descriptors are
treated as a part of a single transaction containing an optional write buffer
followed by an optional read buffer.
All descriptors in the chain must have the same ID.

...

I think you should consider removing  the "same ID" requirement.

Assuming out of order execution, how is the driver supposed to re-assign unique IDs to the previously
chained descriptor?
Do you expected driver to copy original IDs somewhere else before the chaining and then restore them after the chain is
executed?

Thanks,
Ilya