[virtio-dev] RE: [virtio-comment] Re: [PATCH v2 0/2] transport-pci: Introduce legacy registers access using AQ

Parav Pandit
2023-05-16T19:35:45Z

> From: virtio-comment@lists.oasis-open.org <virtio-comment@lists.oasis-
> open.org> On Behalf Of Jason Wang
> Sent: Monday, May 15, 2023 11:55 PM
> > I don’t see how this is being any different than register-offset interface.

> > It bisects more things at hypervisor level that makes things hard to add #12th
> entry.
> >
> >> 1) device features
> >> 2) driver features
> >> 3) queue address
> >> 4) queue size
> >> 5) queue select
> >> 6) queue notify
> >> 7) device status
> >> 8) ISR status
> >> 9) config msix
> >> 10) queue msix
> >> 11) device configuration space
> >>
> >> It focuses on the facilities instead of transport specific details like registers
> (we
> >> don't even need legacy registers in this case), I gives more deterministic
> >> behavior so we don't need to care about the cross registers read/write.
> >>
> > 1.x has these registers at raw level and that seems fine.
>
>
> Note that 1.x has more, the above is dumped from the section of "Legacy
> Interfaces: A Note on PCI Device Layout".

Yeah.
Current two commands proposal has one box to transport legacy registers that follows the legacy semantics.
Above commands in future with legacy commands of this work will be able to work together in future anyway.